G'MIC 2.7 - Process Your Images with Style!

The IMAGE team at the GREYC research laboratory is pleased to announce the release of version 2.7 of G’MIC (GREYC’s Magic for Image Computing), its free, generic, extensible, and probably a little magical, framework for digital image processing.

The previous PIXLS.US article on this open-source framework was published a year ago, in August 2018. This new release is therefore a good opportunity to summarize the main features and milestones of the project’s life over the past twelve months. Fasten your seat belts, the road is long and full of surprises!

Useful links:

• The G’MIC Project
• G’MIC Twitter Feed
• G’MIC Forum on PIXLS.US

1. G’MIC in 300 words

G’MIC is a piece of software that has been developed for more than 10 years now, mainly in C++, by two members of the IMAGE team of the GREYC lab: Sébastien Fourey and David Tschumperlé. It is distributed under the terms of the CeCILL free-software license. GREYC is a French public research laboratory located in Caen, specialized in digital sciences, under the head of three academic institutions: CNRS, University of Caen, and ENSICAEN.

The IMAGE team, one of the seven teams in the laboratory, is composed of researchers, professors, Ph.D. students and engineers, all specialized in the fields of algorithmics and mathematics of image processing.

G’MIC is cross-platform (GNU/Linux, MacOS, Windows, …). It provides various user interfaces for manipulating generic image data, i.e. 2D or 3D hyperspectral images or sequences of images with floating-point values (which indeed includes “usual” color images). Around a thousand different processing functions are already available. However, arbitrarily many features can be added thanks to an integrated scripting language.

The most commonly used G’MIC interfaces are: the gmic command, that can be accessed from the command line (which is an essential complement to ImageMagick or GraphicsMagick), the G’MIC Online Web service, but above all, the plug-in G’MIC-Qt, available for the well-known image editing software GIMP, Krita, and Paint.net. It provides more than 500 different filters to apply on images.

Thanks to its extensible architecture, G’MIC is regularly enhanced with new image processing algorithms, and it is these latest additions that will be discussed in the following sections.

2. Add style to your images!

G’MIC has recently implemented a neat filter for style transfer between two images, available from the G’MIC-Qt plug-in under the “Artistic / Stylize“ entry. The concept of style transfer is quite simple: we try to transform an image (typically a photograph) by transferring the style of another image to it (for example a painting).

The implementation of such a style transfer method is relatively complex: The algorithm must be able to recompose the original photograph by “borrowing” pixels from the style image and intelligently combining them, like a puzzle to be reconstructed, to best match the content of the data to be reproduced, in terms of contours, colors and textures. How easily this is done depends of course on the compatibility between the input image and the chosen style. In computer graphics, most existing implementations of style transfer methods are based on convolutional neural networks, more particularly generative adversarial networks (GANs).

G’MIC implements style transfer in a different way (without relying on neural networks, the scientific article detailing the algorithm is currently being written!). This method is parallelizable and can therefore benefit from all the processing units (cores) available on the user’s computer. The computation time naturally depends on the input image resolution, and the accuracy of the desired reconstruction. On a standard 4-cores PC, it could take tens of seconds for low resolution images (e. g. 800x800), up to several minutes for larger pictures.

As one can imagine, it is a very versatile filter, since we can apply any style to any input image without hard constraints. Some famous paintings are available by default in the filter, in order to propose predefined styles to the user.

Let us be honest, it is not always easy to obtain satisfactory results from the first draft. It is generally necessary to choose your starting images carefully, and to play with the many parameters available to refine the type of rendering generated by the algorithm. Nevertheless, the filter is sometimes able to generate quite interesting outcomes, such as those shown below (the original photo is visible at the top left, the style chosen at the top right, and the result of the style transfer at the bottom). Imagine how long it would take for a graphic designer to make these transformations “by hand”!

Other examples of image stylization can be found on the image gallery, dedicated to this filter. To our knowledge, G’MIC is the only “mainstream” image processing software currently offering a generic style transfer filter, where any style image can be chosen.

A last funny experiment: get a picture of an Alien’s head, like Roswell, and then select a crop of the Mandelbrot fractal set as your style image. Use the transfer filter to generate a “fractal” rendering of your alien head. Then, make the whole world believe that the Mandelbrot set contains the mathematical proof of the existence of aliens… ☺

In short, this filter has a clear creative potential for all kind of artists!

3. Interactive deformation and morphing

This year, G’MIC got an implementation of the RBFs interpolation method (Radial Basis Functions), which is able to estimate a dense interpolated function in any dimension, from a known set of scattered samples (not necessarily located on a regular grid). Thus, it gave us the idea to add distortion filters where the user interaction is focused in adding and moving keypoints over the image. In a second stage, G’MIC interpolates the data represented by these keypoints in order to perform the distortion on the entire image.

Let us start with the “Deformations / Warp [interactive]” filter which, as its name suggests, allows the user to distort an image locally by creating/moving keypoints.

The animation below shows this interactive filter in use, and illustrates the fact that these keypoints can be considered as anchors to the image, when they are moved.

(For those who might be concerned about the portraits photos used in the figures above and below: all these portraits are totally artificial, randomly generated by GANs via the website This Person Does Not Not Exist. No moral prejudices to dread!).

The great advantage of using RBFs-based interpolation is that we do not have to explicitly manage a spatial structure between the keypoints, for instance by defining a mesh (i.e. a “deformation grid”). This gives a greater degree of freedom in the obtained distortion (see Fig.3.3. below). And at the same time, we keep a rather fine control on the local amplitude of the applied distortion, since adding more “identity” keypoints around a region naturally limits the distortion amplitude inside this region.

A short demonstration of this distortion filter is also visible in this Youtube video.

And why not extending this kind of distortion for two images, instead of a single one? This is precisely what the new filter “Deformations / Morph [interactive]” does. It is able to render a morphing sequence between two images (put on two separate layers), using the same interpolation technique that only asks for the user to set colored keypoints which match on both images.

In the example above, keypoints are placed on characteristic areas of both faces (tip of nose, lips, eyebrows, etc.). In practice, this takes no more than 5 minutes. Thanks to these keypoints, the algorithm is able to estimate a global deformation map from one image to another, and can generate temporally “mixed” frames where the elements of the face remain relatively well aligned during the whole morphing sequence.

By comparison, here is what we would obtain by simply averaging the two input images together, i.e. without correcting the displacement of the facial features between both images. Not a pretty sight indeed!

Thus, the morphing filter is able to quickly generate a set of intermediate frames, ranging from the “Source” to the “Target” faces, a sequence that can then be saved as an animation.

Many other use cases of this morphing filter can be considered. The following example illustrates its application to render an animation from two photographs of the same object (a garden gnome), but shot with different DOFs (Depth of Field).

Command line users will be pleased to know that these two filters can be tested very quickly from a shell, as follows:

$ gmic image.jpg x_warp
$ gmic source.jpg target.jpg x_morph
~

4. Ever more colorimetric transformations

For several years, G’MIC has contained colorimetric transformation filters able to simulate the film development process, or to give particular colorimetric moods to images (sunlight, rain, fog, morning, afternoon, evening, night, etc.). In a previous report, we already mentioned these filters, which are essentially based on the use of 3D CLUTs (Color Lookup Tables) for modeling the color transformation.

A 3D CLUT is technically a three-dimensional array that provides for each possible RGB color, a replacement color to apply to the image.

The main interest of these 3D CLUTs is the great variety of transformations they can represent: They can indeed define RGB-to-RGB functions with almost any kind of variations. The only “constraint” of these methods is that all image pixels having the same color will be transformed into pixels that also have an identical color.

The disadvantage, however, is that these 3D CLUTs are relatively data intensive. When you want to embed several hundred different ones in the same piece of software (which is the case in G’MIC), you quickly find yourself with a large volume of data to install and manage. For instance, our friends at RawTherapee offer on their website an additional pack of 294 CLUTs functions to download. All these CLUTs are stored as .png files in a .zip archive with a total size of 402 MB. Even if downloading and storing a few hundred _MB_ is no longer limiting nowadays, it is still quite large for things as simple as color changing filters.

This year, we have therefore carried out important research and development work at the GREYC lab on this topic. The result: a new lossy compression algorithm (with visually imperceptible compression losses) that can generate binary representations of CLUTs with an average compression rate of more than 99%, relative to the data already loslessy compressed. The general idea is to determine an optimal set of color keypoints from which the CLUT can be reconstructed (decompression), and this, with a minimal reconstruction error.

As a result, this original compression method allowed us to offer no less than 763 CLUTs in G’MIC, all stored in a binary file that weights less than 3 MB !

All these color variation filters have been grouped into two separate entries in the G’MIC-Qt plug-in, namely “Colors / Simulate Film” (for analog film simulations), and “Colors / Color Presets” (for other color transformations). Each of these filters provides sub-categories for a structured access to the hundreds of CLUTs available. To our knowledge, this makes G’MIC one of the image processing software with the most colorimetric transformations, while keeping a reasonable size.

Readers interested in the mathematical details of these CLUT compression/decompression algorithms may refer to the scientific paper we wrote about it, as well as the presentation slides that have been presented at the conferences GRETSI’2019 (French conference, in Lille) and CAIP’2019 (International conference, in Salerno).

To finish with this topic, note that we have made an open-source implementation of our decompression algorithm of CLUTs available online (in C++, with 716 CLUTs already included). Discussions have also been initiated for a potential integration as a Darktable module for managing 3D CLUTs.

5. Create palettes by mixing colors

Let us now talk about the recent “Colors / Colorful Blobs” filter which is directly inspired by the original concept of Playful Palette created by the Adobe Research team in 2017. This filter is intended for illustrators (designers and digital painters). The goal: Create color palettes which contain only a few main colors (the ones you want to use in an illustration), but also a few sets of intermediate shades between these colors, in the form of color gradients. An artist is theoretically able to better preserve the color coherence of its artwork, by picking colors only from this palette.

As shown on the figure above, the filter allows the artist to create and move colored “blobs” that, when merged together, create the desired color gradients. The result of the filter is thus an image that the artist can use afterward as a custom 2D color palette.

From a technical point of view, this filter is based on 2D metaballs to model the color blobs. Up to twelve separate blobs can be added and different color spaces can be chosen for the calculation of the color gradient (sRGB, Linear RGB or Lab). The filter also benefits from the recent development of the G’MIC-Qt plug-in that enhances the user interactivity inside the preview widget (a feature we mentioned in a previous report), as seen in the animation below (see also this longer video).

This filter may not be useful for most G’MIC users. But you have to admit, it’s pretty fun, isn’t it?

6. Some more filters

Let us now describe a selection of a few other filters and effects added during the year, perhaps less original than the previous ones (but not completely useless anyway!).

• First of all, the “Rendering / Symmetric 2D Shape” filter is a great help when you want to draw geometric shapes having angular symmetries.

  

  The plane can be subdivided into up to 32 angular pieces, each of which can contain a maximum of six keypoints to define a shape profile, allowing potentially complex and varied shapes to be rendered (such as the super-shuriken below!).

  

• The “Degradations / Self Glitching” filter combines an image with a shifted version of itself, to create a Glitch-art type image. Several bitwise operations (Add, Mul, And, _Or_, Xor,…) can be chosen and you can adjust the shift direction and amplitude, as well as various other controls.

  

  Again, this is not a filter that will necessarily be used every day! But it may be helpful for some people. It was actually added in response to a user request.

• In the same style, the “Degradations / Mess With Bits” filter applies some arithmetic operations to the pixel values, seen as binary numbers (for instance, bit shift and bit inversion). Always with the idea of rendering Glitch art, of course!

  

• The “Degradations / Noise [Perlin]” filter implements the generation of the Perlin noise, a very classical noise model in image synthesis, used for the generation of elevation maps for virtual terrains. Here we propose a multi-scale version of the original algorithm, with up to four simultaneous variation scales.

  

• The “Frames / Frame [Mirror]” filter is also a “tailor-made” effect, to meet the needs of a G’MIC-Qt plug-in user. This photographer wanted to resize his photos to obtain a precise width/height ratio, but without having to crop his images. The solution was instead to add image information at the edges of the picture, by symmetry, in order to obtain the desired ratio. So that’s what this filter does.

  

• Finally, let us mention the upcoming advanced image noise reduction filter, by Iain Fergusson, whose development is still in progress. Iain has been contributing to G’MIC for several years now by implementing and experimenting original denoising filters, and his latest project seems really interesting, with promising results. This video shows this filter in action, a good place to learn a little more about how it works.

Now that we’ve looked at these new filters, it seems important for us to remind that, as in many IT projects, this visible part of the iceberg hides a set of lower-level developments done to improve the interactive possibilities of the G’MIC-Qt plug-in, as well as the performance of the internal scripting language interpreter (the G’MIC language), which is how all these filters and effects are actually implemented. These improvements and incremental slight optimizations of the code base benefit to all filters (even those already available for several years) and it actually represents most of the development time we spend on G’MIC. So, dear users, do not be surprised if no new filters appear for a while. It is probably just because we are doing serious work on the G’MIC framework core!

7. Other notable points in the project life

Here are listed some other important news that have punctuated the life of the project since August 2018.

7.1. We now accept donations!

This is essential news for us: since March 2019, the G’MIC project has been granted permission to collect donations (via Paypal), to help in its maintenance and development!

This is a good thing, because until now, there was no simple way for a public research laboratory as the GREYC, to accept donations for supporting the development of a free software application such as G’MIC, an application used daily by several thousand people around the world. And we have currently no other ways to finance this piece of software in the long term.

Thus, we have partnered with LILA (Libre comme l’Art), a French non-profit organization promoting Arts, Artists and Free Software, who accepted to collect donations for us.

In practice, this is something that has been a little long to set up, but now that the donation system is operational, we hope to benefit from it in the future to make the project development even faster (the possible use of the raised funds is detailed on the donations page, this being of course very dependent on the amount of money collected).

For the sake of transparency, we will post the monthly amount of collected donations on the project website. At this point, we don’t really know what to expect in practice. We will see how these donations evolve. Of course, we would like to thank all those who have already participated (or plan to do so) in supporting our open-source framework for image processing. Our ultimate dream would be, one day, to say that the illustration below is only a distant memory!

7.2. Integrating “Smart Coloring” into GIMP

Let us also mention the work of Jehan, known to PIXLS.US readers as a regular GIMP developer. Jehan has been hired by the GREYC laboratory in September 2018, to work on G’MIC (for a 12-month fixed-term contract), thanks to a grant funded by the INS2I Institute of the CNRS (for which we are grateful).

One of its first missions was to re-implement the G’MIC “Smart Coloring” algorithm (that we had already talked about previously) as a new interactive mode integrated into the existing GIMP “Bucket Fill“ tool.

Jehan described all his work in a blog post, which is strongly recommended for reading. Of course, we don’t want to copy his post here, but we want to mention this activity, and to consider it as another original contribution of the G’MIC project to free software for graphic creation: at the GREYC laboratory, we are really happy and proud to have imagined and developed an image colorization algorithm, which artists can use through a well integrated tool into such a popular piece of software as GIMP!

This intelligent colorization algorithm has been the subject of scientific publications, presentations at the conferences GRETSI’2017, EuroGraphics VMV’2018, as well as at the Libre Graphics Meeting’2019. And it is with a great pleasure we see this algorithm is used in real life, for various realizations (as in this great video of GDQuest, for colorizing sprites for video games, for instance).

Scientific research carried out in a public laboratory, which becomes available for the general public, that is what we want to see!

7.3. Other news related to the G’MIC project

• Recently, a major improvement in the performances of G’MIC under Windows has been achieved, by recoding the random number generator (now reentrant)) and removing some slow mutex which were responsible of performance drops for all filters requiring sequences of random numbers (and there were many!). As a result, some filters are accelerated by a factor of four to six under Windows!

• Since December 2018, our G’MIC-Qt plug-in is available for Paint.net, a free graphic editing software application under Windows (not open-source though). This has been possible thanks to the work of Nicholas Hayes who wrote the glue code allowing the interaction between our G’MIC-Qt plug-in and the host software. Users of Paint.net are now able to benefit from the 500+ filters offered by G’MIC. This plug-in, available here, has already been voted “Best Plug-in of the Year 2018“ by the members of the Paint.net forum ☺ !

• Since October 2018, the G’MIC-Qt plug-in for GIMP has been compiled and proposed for MacOS by a new maintainer, Andrea Ferrero, who is also the main developer of the free software application Photoflow, a non-destructive image editor (more information here). Many thanks Andrea, for this wonderful contribution!

  • Since the announced shutdown of the Google+ social network, we have opened two new accounts, on Framasphere and Reddit, to share news about the project’s life (but the Twitter feed is still our most active account).

• Let us also thank Santa Claus, who kindly brang us a materialized version of our mascot “Gmicky” last year. That looks almost perfect!

  

• The G’MIC project was presented at the FENO, the “Fête de l’Excellence Normande“, from 12 to 14 April 2019, at the Caen Exhibition Centre. We were hosted on the stand of the CNRS Normandie, and we carried out demonstrations of style transfer (teaser) and automatic illumination of clip arts (teaser), for the general public.

  

• And to dig even deeper, here are some other external links we found interesting, and which mention G’MIC in one way or another:
  • A video presentation of the plug-in G’MIC-Qt, by Chris’ Tutorial;
  • The Youtube channel MyGimpTutorialChannel offers a lot of videos showing how to use G’MIC-Qt in GIMP to achieve various effects (mostly in German);
  • The Clinic, a Chilean weekly newspaper, apparently used G’MIC to achieve an effect on one of its covers (via the smoothing filter “Artistic / Dream Smoothing”);
  • Another video tutorial, showing how to use the G’MIC “Artistic / Rodilius” filter to create stylized animal photos.

8. The future

As you see, G’MIC is still an active open-source project, and with its 11 years of existence, it can be considered as mature enough to be used “in production” (whether artistic or scientific).

We have never defined and followed a precise roadmap for the project development: the functionalities come according to the needs of the developers and users (and the limited time we can devote to it!). At the moment, there is a lot of interest in image processing methods based on neural networks, and deep learning techniques. It is therefore possible that one day, some of these methods will be integrated into the software (for instance, we already have a prototyped code running in G’MIC that actually learns from image data with convolutional neural networks, but we are still at the prototyping stage…).

After 11 years of development (make it 20 years, if we include the development of the CImg library on which G’MIC is based), we have reached a point where the core of the project is, technically speaking, sufficiently well designed and stable, so as not to have to rewrite it completely in the next years. In addition, the number of features available in G’MIC already covers a large part of the traditional image processing needs.

The evolution of this project may therefore take several paths, depending on the human and material resources that we will be able to devote to it in the future (for the development, but also in project management, communication, etc.). Achieving an increase in these resources will undoubtedly be one of the major challenges of the coming years, if we want G’MIC to continue its progress (and we already have plenty of ideas for it!). Otherwise, this image processing framework might end up being just maintained in its current (and functional) state. It is of course with a hope for progression that we have recently set up the donation page. We also hope that other opportunities will soon arise to enable us to make this project more visible (you are invited to share this post if you like it!)

That’s it for now, this long post is now over, thank you for holding on until the end, you can resume normal activity! I’ll be happy to answer any questions in the comments.

Post-scriptum: Note that the 3D animation displayed as the teaser image for this post has been actually generated by G’MIC, via the command $ gmic x_starfield3d. An opportunity to remind that G’MIC also has its own _3D_ rendering engine capable of displaying simple objects, which is very practical for scientific visualization! We may have the occasion to talk about it again in a future post…

A special thank you for reviewing and helping to translate this article to:
Patrick David, Sébastien Fourey, Christine Porquet, Ryan Webster.

Quick digiKam Tip: Back up digikamrc file

digiKam stores the current state of the application in the ~/.config/digikamrc file. This file keeps track of pretty much everything: from the database connection profile and custom toolbar settings, to the last-used curve and sharpening parameters. So next time you install or reinstall digiKam, don’t forget to back up the digikamrc file. This way, you don’t have to configure a fresh digiKam installation from scratch. Simply copy the file to a safe location or external storage device, and drop the file into the ~/.config folder before you run digiKam.

Location Tracking for Photographers with GPS Logger and Trekarta

When it comes to Android apps for photographers, we are spoiled for choice. From depth-of-field and golden hour calculators to sun position and remote control apps – there are plenty of clever tools to choose from. But there is one particular app combination that can prove to be indispensable for any photographer on the move: a GPS logger and a GPX viewer. There are two main reasons for that.

1. Tracking your movements and saving them in the GPX format can come in handy for geotagging photos.

2. The ability to attach comments to the current location allows you to use the GPS logging app to note places you either photographed or you plan to photograph later. You can then use a GPX viewer app to see and manage bookmarked locations.

There are several apps that offer GPS logging and viewing, but you can’t go wrong with GPS Logger for Android and Trekarta. Both apps are released under an open source license, and they are available free of charge on Google Play and F-Droid.

How you set up GPS Logger for Android is a matter of personal preference. One way to go is to configure the app to automatically start tracking on boot and upload tracks to the desired destination (e.g., a NAS or a file sharing service).

Once GPS Logger for Android is running, adding a comment to the current location is as easy as pulling down the notification drawer and tapping Comment. The app saves the tracks as GPX files in the Android/data/com.mendhak.gpslogger/files directory on your Android device. To view a GPX file in Trekarta, use a file manager to navigate to the directory, and use Android’s sharing functionality to send the desired GPX file to Trekarta.

New Topic Previews

Image previews now available for some categories

I’ve been a member of the community over at blenderartists.org (previously elysiun) for a long time (it’ll be 15 years this October according to my profile there). So it was nice to see when they finally transitioned to using Discourse a little while back.

What I really liked, though, was the work that Bart did to specific pages and tag lists to display them. Here’s what their current homepage looks like:

They use a different default main page style, “Categories” view, than we do (“Latest”). This just shows the site categories as a column on the left, then the latest posts in a column on the right.

The row of featured images along the top is actually part of a plugin that I’ll get to in a moment.

If you want to change your own default main page view of the forums, you can modify it at your account Preferences → Interface (and change it to Categories):

Fancy Category Views

The default landing page is neat, but what they did with their forum gallery page is much neater:

They set up the Topic List Previews plugin so the entire category is actually viewed as a tile of images. I think we can all agree that this is generally a much nicer way to view categories that are heavily image-based. Of course, I thought this was a natural fit for us as well!

So through the magic of having an invaluable resource like a darix, he was able to make it a reality for us!

We’ve got it implemented now on the Play Raw category (now its own sub-category under the Processing category), the Critique, and the Showcase category. If you haven’t had a chance to check it out yet, please do. (darix announced it in the thread Play raw posts and you so feel free to give us any further feedback in that topic.)

Keep in mind that for those categories, the preview image will correspond to the first image in the first post. Try to remember to make the first image in those category topics the one you’ll want in the preview.

We haven’t enabled the featured row of images after some initial feedback. We may revisit it again at some point, but hopefully the Play Raw and Showcase categories will look a little better now. It certainly makes the categories a little easier and faster to navigate now that you can see the previews directly on the page.

G'MIC Finally Accepts Donations

Help support an awesome team!

For years the incredible team over at G’MIC (GREYC’s Magic for Image Computing) have been producing an incredible image processing system and many awesome filters to go along with it. They’ve got an very active and awesome community right here on their forums and they’ve been producing all manner of neat processing filters for photographers, digital artists, and scientists.

Due to the project being under the auspices of a French Research Lab, the GREYC laboratory in Caen, France, they were limited in being able to accept any donations.

Until now!

To avoid burying the lede, go and make a donation to the fabulous folks of the G’MIC project: https://libreart.info/en/projects/gmic.

I first heard about GREYCstoration (proto-G’MIC) a long time ago (over 10 years) as the only really viable Free Software image denoising option for photographers. It allowed me to de-noise images on par (or better in many cases) with the then popular Noise Ninja. It’s been an essential part of my toolkit ever since!

Back then David Tschumperlé was really only looking for postcards from users as a “thank you” and maybe some occasional donations to pay for hot chocolates during the day. I finally got to buy him a milkshake while at the Libre Graphics Meeting 2014 in Leipzig, Germany and for the value he has provided me with his software I owe him many, many more!

Value is exactly what I want to bring up in this post. I’m sure many here have had an opportunity to use G’MIC in some form and any attempt at listing the wide range of filters and capabilities it provides would not do it justice. If you’ve realized some value from the project, now is the time to show some love.

I’ve been lucky to call David a friend for a long time now and I can personally attest to his kindness and sincerity. With that in mind I implore you: if you have a few spare dollars, euros, yen, pesos, or gold bullion please consider donating to the project and make sure the milkshakes (or hot chocolates) never stop flowing. David (and Sébastien Fourey!) are a sound investment in providing high value to Free Software artists and photographers!

Donate to the G’MIC project!

(David is too modest to really come out and ask for support but “modest” isn’t really in my vocabulary - so go donate!)

LILA

For a long time David was unable to accept donations from community members. There were some concerns from the research institution his lab is a part of in France. Just recently, though, they managed to reach an agreement where the funds flow through a French non-profit called Libre Comme L’Art, LILA, that includes the fabulous Jehan Pagès of the GIMP team as a member and where the ZeMarmot animated film is being produced.

A big “Thank You!” to Jehan and LILA for making this possible!

Libre Graphics Meeting 2019

Let's participate!

It’s that time of year again: Libre Graphics Meeting 2019 is fast approaching!

This year the meeting will be May 29 to June 2 in Saarbrücken, Germany. This is extra exciting because Saarbrücken is centrally located enough that we should have a nice representation from projects and community members. Members of both RawTherapee and darktable live nearby and will be in attendance (along with others from those projects and many others).

Participate!

I’m hoping to have a good representation this year, so first and foremost - please, please consider participating by giving a presentation, leading a workshop, or even a quick lightning talk! The Call for Participation page is here:

https://libregraphicsmeeting.org/2019/call-for-participation/

I will make myself available to help in any way I can. If you want a hand with the presentation, design, graphics or whatever please feel free to ping me (also - remember that we try to archive all of our presentations and material in our Github repo so you can grab any of the assets from there as well)! This is a great opportunity to spread the word about what we’re up to and the many, many awesome projects everyone has created, maintained, and contributed to for Free Software photography.

The deadline for submittal is coming up on January 15^th!
If you think you’d like to present or host a workshop please submit as soon as possible.

Cheers!

I am particularly excited about this meeting because a) I don’t get to attend every year so this is the first time I’m able to make it in a few years, and b) this is a great opportunity to really get a bunch of community members to come together! Saarbrücken is on the high-speed rail network so it’s readily accessible from many places (now you have less excuses to not make it).

I love hanging out with y’all. It’s great to nerd out about photography and catch up. Sometimes it really helps to be able to speak face-to-face and this is the perfect opportunity to also be exposed to all manner of other Free Software projects (or to expose ourselves to others?).

Besides, how else am I going to capture some fun photos of y’all?

What’s Going On

We have a few things planned for sure at the meeting and you’re going to be really sad if you miss them by not coming!

1. PIXLS.US BoF (Birds of a Feather)
   This is a special session set aside for a couple of hours for the entire community to get together and chat about what’s going on, what we’d like to do, and what’s coming up.
2. Photowalk
   I’ve been doing photowalks every year that I’ve been because this is almost the ultimate way for me to spend time with folks (unless we can do a beer drinking photowalk all at the same time…).
3. PIXLS.US Presentation/Update
   I’ll (We’ll? Anyone from the community is more than welcome to help me present on this) present on the community and what we’ve done so far and what we’d like to accomplish moving forward. This is our primary way of reporting out to the wider community who we are and what we’re doing.
4. State of the LGM
   This is a couple of slides that are included at the beginning of the program giving an overview of the state of the entire libre graphics ecosystem.

I really, really, really want to be able to add to this list with other presentations (or lightning talks, etc) that the community will give! I may even submit a couple of presentations to talk not just about the community but maybe about our technical work coordinating the forum and providing services for the projects (as well as invite other related projects to come join us).

We can make this an incredible and memorable meeting with a fantastic opportunity to meet friends in person and have a wonderful time!

Goodbye Google Analytics

A little less tracking for the new year

Over on my personal website I decided to stop using third party trackers and assets to keep from exposing visitors to unintended tracking. Third party assets expose a user to being tracked and analyzed by those third (or fourth, or more) parties and honestly this is something the web could use a little (lot) less of. I loved having stats early on when we started this crazy idea for a community and as I mentioned on my blog post, it’s a Faustian bargain to get stats at the expense of allowing Google to track what all the users of the site are doing. No thanks.

I figure it’s the eve of a new year so why not start it out right and reduce the tracking footprint of the site?

This all started by noticing that some new browser feature strips referer information from requests (thanks @darix) and we were using them to target specific areas of websites that we manage comments for. It came to my attention when I was reading the release announcement for digiKam 6.0.0 beta 3.

While fixing that problem, I found that once we fixed the referer requirement problem I was still seeing issues with Privacy Badger blocking our embed code. On further inspection it boiled down to using Google Analytics on our base domain (pixls.us) and having a cookie set by Google, which then got sent with embed requests from other websites (digiKam and darktable). This triggered the heuristic blocking by Privacy Badger.

Honestly, we derive very little value from the analytics for the price (privacy) we pay to use it. Better to simply remove it.

We still do analytics but we own the stack ourselves (thank you so much andabata!). If you want to block our own analytics the domain is: piwik.pixls.us.

2018 PlayRaw Calendar

Chris creates a new calendar for the community

Last year I got an amazing surprise in the mail. It was an awesome calendar of a handpicked selection of results from the years PlayRaw images.

Chris (@chris) put together another fantastic calendar for this year (while juggling kids, too) and it’s too nice to not have a post about it!

It was a really awesome surprise to recieve my calendar last year - and I wish I would have planned a little better to be able to grab a photo of the calendar hanging in my office (it’s my work desk calendar - it never fails to remind me that there’s more fun things to life than work - also that I need to up my processing game… ).

This year Chris has done it again by assembling a wonderfully curated collection of images and edits from the various Play Raws that were posted this year. I’ve plagiarized his post on the forums to put together this post and get some more publicity for his time and effort!

If you get a moment, please thank Chris for his work putting this together!

You can download the PDF: 2018 Play Raw Calendar

Here are the images he chose for the calendar and the edits he included:

A preview (also shamelessly lifted from Chris’s forum post):

These Play Raws are a ton of fun and one of the great aspects of having such a generous community to share the images and allowing everyone to practice and play. I am constantly humbled by the amazing work our community produces and shares with everyone.

Thank you to everyone who shared image and participated in processing (and sharing how you achieved your results)! I have really learned some neat things based on others work and look forward to even more opportunities to play (pun intended).

Fun side note: the Play Raws are actually something that began on the old RawTherapee forums. When they moved their official forums here with us it was one of those awesome things I’m glad they brought over with them (the people were pretty great too… :)).

Giving More Thanks

For an awesome community

It is a yearly tradition for us to post something giving thanks around this holiday. I think it’s because this community has become such a large part of our lives. Also, I think it helps to remind ourselves once in a while of the good things that happen to us. So in that spirit…

Financial Supporters

We are lucky enough (for now) to not have huge costs, but they are costs none-the-less. We have been very fortunate that so many of you have stepped up to help pay those costs.

The Goliath of Givers

For the last several years, Dimitrios Psychogios has graciously covered our server expenses (and then some). On behalf of the community, thank you so much! You keep the servers up and running. Your generosity will cover infrastructure costs for the year and give us room to grow as the community does.

We also have some awesome folks who support us through monthly donations (which are nice because we can plan better if we need to). Together they cover the costs of data storage + transfer in/out of Amazon AWS S3 storage (basically the storage and transfer of all of the attachments and files in the forums). So thank you, you cool friends, you make the cogs turn:

• Jonas Wagner
• elGordo
• Chris
• Christian
• Claes
• Thias
• Stephan Vidi
• ukbanko
• Bill Z
• Damon Hudac
• Luka Stojanovic (a multi-year contributor!)
• Moises Mata
• WoodShop Artisans
• Barrie Minney (He’s a long time monthly contributor!)
• Mica

It is so amazing not to have to worry about finding the capital to support our growing community; we just expand things as necessary. It is super great.

If you’d like to join them in supporting the site financially, check out the support page.

Growth

As of today, we have 3135 users, so we’ve continued to grow at a very good rate! Welcome to all the new users.

As you can see from our discuss stats, we’re approaching 500k page views per month:

And our yearly community health is very positive:

gPhoto

This year we added the gphoto project to our list of supported applications! gPhoto is an awesome library for interfacing with your camera. It is used by darktable and entangle to allow you to shoot with your camera attached to your laptop or other device. We’re thrilled that they’ve joined us on the forums!

Natron

Natron is a compositing application mostly used in 3D/video compositing. The main developer was looking to give the project more of a community focus, so of course we were happy to provide them their own spot in the forum for their users to communicate and collaborate.

darix

For another year, @darix continues to keep our stuff up and running! Do you ever notice outages? No?! Me either, and that is due to his daily diligence. We can’t thank him enough for his dedication to our community.

patdavid or Pat David

The originator of it all, thank you for the initial push to create this community where we are not divided by which application we use. And for your continued good will towards everyone here, your welcoming spirit, and passion. We’d never have done it without you! And for all the great things to come!

All of You

The community is the sum of parts + all the extra love that comes from all of you! Thank you so much continuing to stick around, share you knowledge, and spread the great community. It keeps me motivated, creative, and challenged and for that I am very thankful.

Support Andrea Ferrero on Patreon!

Andrea is developing Photo Flow, GIMP AppImage, Hugin AppImage, and more!

Andrea Ferrero, or as we know him Carmelo_DrRaw, has been contributing to the PIXLS.US community since April of 2015. A self described developer and photography enthusiast, Andrea is the developer of the PhotoFlow image editor, and is producing AppImages for:

• The GIMP image manipulation program - weekly AppImage packages from stable releases and development branches.
• The RawTherapee editor - nightly AppImage and Windows packages from stable and development branches
• LuminanceHDR - nightly AppImage packages for Linux
• HDRMerge - nightly AppImage packages for Linux
• The Hugin panorama photo stitcher - AppImages for stable releases and development branches

Andrea is the best sort of community member, contributing six different projects (including his own)! He is always thoughtful in his responses, does his own support for PhotoFlow, and is kind and giving. He has finally started a Patreon page to support his all of his hard work. Support him now!

He was also kind enough to answer a few questions for us:

PX: When did you get into photography? What’s your favorite subject matter?

AF: I think I was about 15 when I got my first reflex, and I was immediately fascinated by macro-photography. This is still what I like to do the most, together with taking pictures of my kids. ;-) By the way, you can visit my personal free web gallery on GitHub: http://aferrero2707.github.io/photorama/gallery/ (adapted from this project).

It is still a work in progress, but you are welcome to fork it and adapt it to your needs if you find it useful!

PX: What brought you to using and developing Free/Open Source Software?

AF: I started to get interested in programming when I was at the university, in the late 90’s. At that time I quickly realized that the easiest way to write and compile my code was to throw Linux into my hard drive. Things were not as easy as today but I eventually managed to get it running, and the adventure began.

A bit later I started a scientific career (nothing related to image processing or photography, so I won’t bother with more details about my daily job), and since then I have been a user of Linux-based computing clusters for almost 20 years at the time of writing… A large majority of the software tools I use at work are free and open sourced and this definitely has marked my way of thinking and developing.

PX: What are some new/exciting features you develop in Photo Flow?

AF: Currently I am mostly focusing on HDR processing and high-quality Dynamic Range compression - what is also commonly called shadows/highlights compression.

More generally, there is still a lot of work to do on the performances side. The software is already usable and quite stable, but some of the image filters are still a bit too slow for real-time feedback, especially when combined together.

The image exporting module is also currently in a state of work in progress. It is already possible to select either Jpeg or TIFF (8, 16 or floating-point 32 bits bit depth) as the output format, to resize the image and add some post-resize sharpening, and to select the output ICC profile. What is still missing is a real-time preview of the final result, with a possibility to soft-proof the output profile. The same options need to be included in the batch processor as well.

On a longer term, and if there is some interest from the community, I am thinking about porting the code to Android in a simplified form that would be suitable for tablets and the like. The small memory footprint of the program could be an important advantage on such systems.

PX: What other applications would you like to make an AppImage for? Have you explored Snaps or Flatpaks?

AF: I am currently developing and refining AppImage packages for GIMP, RawTherapee, LuminanceHDR and HDRMerge, in addition to PhotoFlow. All packages are automatically built and deployed through Travis CI, for better reproducibility and increased security. Hugin is the next application that I plan to package as an AppImage.

All the AppImage projects are freely available on GitHub. That’s also the best place for any feedback, bug report, or suggestion.

There is an ongoing discussion with the GIMP developers about the possibility to provide the AppImage as an official download.

In addition to the AppImage packages, I am also working with the RawTherapee developers on cross-compiled Windows packages that are also automatically built on Travis CI. The goal is to help them provide up-to-date packages from the main development branches, so that more users can test them and provide feedback.

I’m also open to any suggestions for additional programs that could be packaged as AppImages, so do not hesitate to express your wishes!

Personally I am a big fan of the AppImage idea, mostly because, unlike Snap or Flatpack packages, it is not bound to any specific distribution or run-time environment. The packager has full control over the contents of the AppImage package, pretty much like MacOS bundles.

Moreover, I find the community of developers around the AppImage format very active and open-minded. I am currently collaborating to improve the packaging of GTK applications. For those who are interested in the details, the discussion can be followed here: https://github.com/linuxdeploy/linuxdeploy/issues/2

G'MIC 2.3.6

10 Years of Open Source Image Processing!

The IMAGE team of the GREYC laboratory is happy to celebrate the 10th anniversary of G’MIC with you, an open-source (CeCILL), generic and extensible framework for image processing. GREYC is a public research laboratory on digital technology located in Caen, Normandy/France, under the supervision of 3 research institutions: the CNRS (UMR 6072), the University of Caen Normandy and the ENSICAEN engineering school.

This celebration gives us the perfect opportunity to announce the release of a new version (2.3.6) of this free software and to share with you a summary of the latest notable changes since our last G’MIC report, published on PIXLS.US in February 2018.

Related links:

• The G’MIC project
• Twitter feed
• Announcement of the first version of G’MIC on LinuxFr.org [fr]
• Previous article about G’MIC on PIXLS.US

(Click on the images of the report to display them in full resolution)

1. Looking back at 10 years of development

G’MIC is a multiplatform framework (GNU/Linux, macOS, Windows…) providing various user interfaces for manipulating generic image data, such as 2D or 3D hyperspectral images or image sequences with float values (thus including “normal” color images). More than 1000 different operators for image processing are included, a number that is extensible at will since users can add their own functions by using the embedded script language.

It was at the end of July 2008 that the first lines of G’MIC code were created (in C++). At that time, I was the main developer involved in CImg, a lightweight open source C++ library for image processing, when I made the following observation:

• The initial goal of CImg, which was to propose a “minimal” library of functions to help C++ developers to develop image processing algorithms, was broadly achieved; most of the algorithms I considered as essential in image processing were integrated. CImg was initially meant to stay lightweight, so I didn’t want to include new algorithms ad vitam æternam, which would be too heavy or too specific, thus betraying the initial concept of the library.
• However, this would only cater to a rather small community of people with both C++ knowledge and image processing knowledge! One of the natural evolutions of the project, creating bindings of CImg to other programming languages, didn’t appeal much to me given the lack of interest I had in writing the code. And these potential bindings still only concerned an audience with some development expertise.

My ideas were starting to take shape: I needed to find a way to provide CImg processing features for non-programmers. Why not attempt to build a tool that could be used on the command line (like the famous convert command from Imagemagick)? A first attempt in June 2008 (inrcast, presented on the French news site LinuxFR), while unsuccessful, allowed me to better understand what would be required for this type of tool to easily process images from the command line.

In particular, it occurred to me that conciseness and coherence of the command syntax were the two most important things to build upon. These were the aspects that required the most effort in research and development (the actual image processing features were already implemented in CImg). In the end, the focus on conciseness and coherence took me much further than originally planned as G’MIC got an interpreter) of its own scripting language, and then a JIT compiler for the evaluation of mathematical expressions and image processing algorithms working at the pixel level.

With these ideas, by the end of July 2008, I was happy to announce the first draft of G’MIC. The project was officially up and running!

A few months later, in January 2009, enriched by my previous development experience on GREYCstoration (a free tool for nonlinear image denoising and interpolation, from which a plug-in was made for GIMP), and in the hopes of reaching an even larger public, I published a G’MIC GTK plug-in for GIMP. This step proved to be a defining moment for the G’MIC project, giving it a significant boost in popularity as seen below (the project was hosted on Sourceforge at the time).

The sudden interest in the plugin from different users of GIMP (photographers, illustrators and other types of artists) was indeed a real launchpad for the project, with the rapid appearance of various contributions and external suggestions (for the code, management of the forums, web pages, writing of tutorials and realization of videos, etc.). The often idealized community effect of free software finally began to take off! Users and developers began to take a closer look at the operation of the original command-line interface and its associated scripting language (which admittedly did not interest many people until that moment!). From there, many of them took the plunge and began to implement new image processing filters in the G’MIC language, continuously integrated them into the GIMP plugin. Today, these contributions represent almost half of the filters available in the plugin.

Meanwhile, the important and repeated contributions of Sébastien Fourey, colleague of the GREYC IMAGE team (and experienced C++ developer) significantly improved the user experience of G’MIC. Sébastien is indeed at the heart of the main graphical interface development of the project, namely:

• The G’MIC Online web service (which was later re-organised by GREYC’s Development Department).
• Free Software ZArt, a graphical interface - based on the _Qt_ library - for the application of G’MIC filters to video sequences (from files or digital camera streams).
• And above all, at the end of 2016, Sébastien tackled a complete rewrite of the G’MIC plugin for GIMP in a more generic form called G’MIC-Qt. This component, also based on the _Qt_ library (as the name suggests), is a single plugin that works equally well with both GIMP and Krita, two of the leading free applications for photo retouching/editing and digital painting. G’MIC-Qt has now completely supplanted the original GTK plugin thanks to its many features: built-in filter search engine, better preview, superior interactivity, etc. Today it is the most successful interface of the G’MIC project and we hope to be able to offer it in the future for other host applications (contact us if you are interested in this subject!).

The purpose of this article is not to go into too much detail about the history of the project. Suffice it to say that we have not really had time to become bored in the last ten years!

Today, Sébastien and I are the two primary maintainers of the G’MIC project (Sébastien mainly for the interface aspects, myself for the development and improvement of filters and the core development), in addition to our main professional activity (research and teaching/supervision).

Let’s face it, managing a free project like G’MIC takes a considerable amount of time, despite its modest size (~120k lines of code). But the original goal has been achieved: thousands of non-programming users have the opportunity to freely and easily use our image processing algorithms in many different areas: image editing, photo manipulation, illustration and digital painting, video processing, scientific illustration, procedural generation, glitch art…

The milestone of 3.5 million total downloads was exceeded last year, with a current average of about 400 daily downloads from the official website (figures have been steadily declining in recent years as G’MIC is becoming more commonly downloaded and installed via alternative external sources).

It is sometimes difficult to keep a steady pace of development and the motivation that has to go with it, but we persisted, thinking back to the happy users who from time to time share their enthusiasm for the project!

Obviously we can’t name all the individual contributors to G’MIC whom we would like to thank, and with whom we’ve enjoyed exchanging during these ten years, but our heart is with them! Let’s also thank the GREYC laboratory and INS2I institute of CNRS for their strong support for this free project. A big thank you also to all the community of PIXLS.US who did a great job supporting the project (hosting the forum and publishing our articles on G’MIC).

But let’s stop reminiscing and get down to business: new features since our last article about the release of version 2.2!

2. Automatic illumination of flat-colored drawings

G’MIC recently gained a quite impressive new filter named « Illuminate 2D shape », the objective of which is to automatically add lit zones and clean shadows to flat-colored 2D drawings, in order to give a 3D appearance.

First, the user provides an object to illuminate, in the form of an image on a transparent background (typically a drawing of a character or animal). By analyzing the shape and content of the image, G’MIC then tries to deduce a concordant 3D elevation map (“ bumpmap “). The map of elevations obtained is obviously not exact, since a 2D drawing colored in solid areas does not contain explicit information about an associated 3D structure! From the estimated 3D elevations it is easy to deduce a map of normals (“ normalmap “) which is used in turn to generate an illumination layer associated with the drawing (following a Phong Shading model).

This new filter is very flexible and allows the user to have a fairly fine control over the lighting parameters (position and light source rendering type) and estimation of the 3D elevation. In addition the filter gives the artist the opportunity to rework the generated illumination layer, or even directly modify the elevation maps and estimated 3D normals. The figure below illustrates the process as a whole; using the solid colored beetle image (top left), the filter fully automatically estimates an associated 3D normal map (top right). This allows it to generate renditions based on the drawing (bottom row) with two different rendering styles: smooth and quantized.

Despite the difficulty inherent in the problem of converting a 2D image into 3D elevation information, the algorithm used is surprisingly effective in a good many cases. The estimation of the 3D elevation map obtained is sufficiently consistent to automatically generate plausible 2D drawing illuminations, as illustrated by the two examples below - obtained in just a few clicks!

It occurs, of course, that the estimated 3D elevation map does not always match what one might want. Fear not, the filter allows the user to provide “guides” in the form of an additional layer composed of colored lines, giving more precise information to the algorithm about the structure of the drawing to be analyzed. The figure below illustrates the usefulness of these guides for illuminating a drawing of a hand (top left); the automatic illumination (top right) does not account for information in the lines of the hand. Including these few lines in an additional layer of “guides” (in red, bottom left) helps the algorithm to illuminate the drawing more satisfactorily.

If we analyze more precisely the differences obtained between estimated 3D elevation maps with and without guides (illustrated below as symmetrical 3D objects), there is no comparison: we go from a very round boxing glove to a much more detailed 3D hand estimation!

Finally, note that this filter also has an interactive preview mode, allowing the user to move the light source (with the mouse) and have a preview of the drawing illuminated in real time. By modifying the position parameters of the light source, it is thus possible to obtain the type of animations below in a very short time, which gives a fairly accurate idea of the 3D structure estimated by the algorithm from the original drawing.

A video showing the various possible ways to edit the illumination allowed by this filter is visible here. The hope is this new feature of G’MIC allows artists to accelerate the illumation and shading stage of their future drawings!

3. Stereographic projection

In a completely different genre, we have also added a filter implementing stereographic projection, suitably named “Stereographic projection“. This type of cartographic projection makes it possible to project planar defined image data onto a sphere. It should be noted that this is the usual projection used to generate images of “mini-planets” from equirectangular panoramas, like the one illustrated in the figure below.

If we launch the G’MIC plugin with this panorama and select the filter “Stereographic projection“, we get:

The filter allows precise adjustments of the projection center, the rotation angle, and the radius of the sphere, all interactively displayed directly on the preview window (we will come back to this later). In a few clicks, and after applying the filter, we get the desired “mini-planet”:

It is also intruiging to note that simply by reversing the vertical axis of the images, we transform a “mini-planet” into a “max-tunnel”!

Again, we made this short video which shows this filter used in practice. Note that G’MIC already had a similar filter (called “Sphere“), which could be used for the creation of “mini-planets”, but with a type of projection less suitable than the stereographic projection now available.

4. Even more possibilities for color manipulation

Manipulating the colors of images is a recurring occupation among photographers and illustrators, and G’MIC already had several dozen filters for this particular activity - grouped in a dedicated category (the originally named “Colors“ category!). This category is still growing, with two new filters having recently appeared:

• The “CLUT from after-before layers“ filter tries to model the color transformation performed between two images. For example, suppose we have the following pair of images:

Problem: we do not remember at all how we went from the the original image to the modified image, but we would like to apply the same process to another image. Well, no more worries, call G’MIC to the rescue! The filter in question will seek to better model the modification of the colors in the form of a HaldCLUT, which happens to be a classic way to represent any colorimetric transformation.

The HaldCLUT generated by the filter can be saved and re-applied on other images, with the desired property that the application of the HaldCLUT on the original image produces the target model image originally used to learn the transformation. From there, we are able to apply an equivalent color change to any other image:

This filter makes it possible in the end to create HaldCLUT “by example”, and could therefore interest many photographers (in particular those who distribute compilations of HaldCLUT files, freely or otherwise!).

• A second color manipulation filter, named “Mixer [PCA]“ was also recently integrated into G’MIC. It acts as a classic color channel mixer, but rather than working in a predefined color space (like sRGB, HSV, Lab…), it acts on the “natural” color space of the input image, obtained by principal component analysis (PCA) of its RGB colors. Thus each image will be associated with a different color space. For example, if we take the “lion” image below and look at the distribution of its colors in the RGB cube (right image), we see that the main axis of color variation is defined by a straight line from dark orange to light beige (axis symbolized by the red arrow in the figure).

The secondary axis of variation (green arrow) goes from blue to orange, and the tertiary axis (blue arrow) from green to pink. It is these axes of variation (rather than the RGB axes) that will define the color basis used in this channel mix filter.

It would be wrong to suggest that it is always better to consider the color basis obtained by PCA for the mixing of channels, and this new filter is obviously not intended to be the “ultimate” mixer that would replace all others. It simply exists as an alternative to the usual tools for mixing color channels, an alternative whose results proved to be quite interesting in tests of several images used during the development of this filter. It does no harm to try in any case…

5. Filter mishmash

This section is about a few other filters improved or included lately in G’MIC which deserve to be talked about, without dwelling too much on them.

• Filter “Local processing” applies a color normalization or equalization process on the local image neighborhoods (with possible overlapping). This is an additional filter to make details pop up from under or over-exposed photographs, but it may create strong and unpleasant halo artefacts with non-optimal parameters.

  

• If you think that the number of layer blending modes available in GIMP or Krita is not enough, and dream about defining your own blending mode formula, then the recent improvement of the G’MIC filter « Blend [standard] » will please you! This filter now gets a new option « Custom formula » allowing the user to specify their own mathematical formula when blending two layers together. All of your blending wishes become possible!

  

• Also note the complete re-implementation of the nice “Sketch“ filter, which had existed for several years but could be a little slow on large images. The new implementation is much faster, taking advantage of multi-core processing when possible.

  

• A large amount of work has also gone into the re-implementation of the “Mandelbrot - Julia sets“ filter, since the navigation interface has been entirely redesigned, making exploration of the Mandelbrot set much more comfortable (as illustrated by this video). New options for choosing colors have also appeared.

  

• In addition, the “Polygonize [Delaunay]“ filter that generates polygonized renderings of color images has a new rendering mode, using linearly interpolated colors in the Delaunay triangles produced.

  

6. Other important highlights

6.1. Improvements of the plug-in

Of course, the new features in G’MIC are not limited to just image processing filters! For instance, a lot of work has been done on the graphical interface of the plug-in G’MIC-Qt for GIMP and Krita:

• Filters of the plug-in are now allowed to define a new parameter type point(), which displays as a small colored circle over the preview window. The user can drag this circle and move it with the mouse. As a result this can give the preview widget a completely new type of user interaction, which is no small thing! A lot of filters now use this feature, making them more pleasant to use and intuitive (look at this video for some examples). The animation below shows for instance how these new interactive points has been used in the filter « Stereographic projection » described in previous sections.

• In addition, introducing these interactive points has allowed improving the split preview modes, available in many filters to display the « before/ after » views side by side when setting the filter parameters in the plug-in. It is now possible to move this « before/ after » separator, as illustrated by the animation below. Two new splitting modes (« Checkered » and « Inverse checkered » ) have been also included alongside it.

A lot of other improvements have been made to the plug-in: the support of the most recent version of GIMP (2.10), of Qt 5.11, improved handling of the error messages displayed over the preview widget, a cleaner designed interface, and other small changes have been made under the hood, which are not necessarily visible but slightly improve the user experience (e.g. an image cache mechanism for the preview widget). In short, that’s pretty good!

6.2. Improvements in the software core

Some new refinements of the G’MIC computational core have been done recently:

• The “standard library” of the G’MIC script language was given new commands for computing the inverse hyperbolic functions (acoss, asinh and atanh), as well as a command tsp (travelling salesman problem) which estimates an acceptable solution to the well-known Travelling salesman problem, and this, for a point cloud of any size and dimension.

  

  

• The demonstration window, which appears when gmic is run without any arguments from the command line, has been also redesigned from scratch.

• The embedded JIT compiler used for the evaluation of mathematical expressions has not been left out and was given new functions to draw polygons (function polygon()) and ellipses (function ellipse()) in images. These mathematical expressions can in fact define small programs (with local variables, user-defined functions and control flow). One can for instance easily generate synthetic images from the command line, as shown by the two examples below.

Example 1

$ gmic 400,400,1,3 eval "for (k = 0, k<300, ++k, polygon(3,u([vector10(0),[w,h,w,h,w,h,0.5,255,255,255])))"

Result:

Example 2

$ gmic 400,400,1,3 eval "for (k=0, k<20, ++k, ellipse(w/2,h/2,w/2,w/8,k*360/20,0.1,255))"

Result:

• Note also that NaN values are now better managed when doing calculus in the core, meaning G’MIC maintains coherent behavior even when it has been compiled with the optimisation -ffast-math. Thus, G’MIC can be flawlessly compiled now the maximum optimization level -Ofast supported by the compiler g++, whereas we were restricted to the use of -O3 before. The improvement in computation speed is clearly visible for some of the offered filters !

6.3. Distribution channels

A lot of changes have also been made to the distribution channels used by the project:

• First of all, the project web pages (which are now using secured https connections by default) have a new image gallery. This gallery shows both filtered image results from G’MIC and the way to reproduce them (from the command line). Note that these gallery pages are automatically generated by a dedicated G’MIC script, which ensures the displayed command syntax is correct.

  

This gallery is split into several sections, depending on the type of processing done (Artistic, Black & White, Deformations, Filtering, etc.). The last section « Code sample » is my personal favorite, as it exhibits small animations (shown as looping animated GIFs) which have been completely generated from scratch by short scripts, written in the G’MIC language. Quite a surprising use of G’MIC that shows its potential for generative art.

• We have also moved the main git source repository of the project to Framagit, still keeping one synchronized mirror on Github at the same place as before (to benefit from the fact that a lot of developers have already an account on Github which makes it easier for them to fork the project and write bug reports).

7. Conclusions and Perspectives

Voilà! Our tour of news (and the last six months of work) on the G’MIC project comes to an end.

We are happy to be celebrating 10 years with the creation and evolution of this Free Software project, and to be able to share with everyone all of these advanced image processing techniques. We hope to continue doing so for many years to come!

Note that next year, we will also be celebrating the 20th anniversary of CImg, the C++ image processing library (started in November 1999) on which the G’MIC project is based, proof that interest in free software is enduring.

As we wait for the next release of G’MIC, don’t hesitate to test the current version. Freely and creatively play with and manipulate your images to your heart’s content!

Thank you, Translators: (ChameleonScales, Pat David)

Welcoming the gPhoto Project to the PIXLS.US community!

Helping the community one project at a time

A major goal of the PIXLS.US effort is to do whatever we can do to help developers of projects unburden themselves from administrating their project. We do this, in part, by providing forum hosting, participating in support, providing web design, and doing community outreach. With that in mind, we are excited to welcome the gPhoto Projects to our discuss forum!

The Entangle interface, which makes use of libgphoto.

You may not have heard of gPhoto, but there is a high chance that you’ve used the project’s software. At the heart of the project is libgphoto2, a portable library that gives application access to hundreds of digital cameras. On top of the foundational library is gphoto2, a command line interface to your camera that supports almost everything that the library can do. The library is used in a bunch of awesome photography applications, such as digiKam, darktable, entangle, and GIMP. There is even a FUSE module, so you can mount your camera storage as a normal filesystem.

gPhoto was recruited to the PIXLS.US community when @darix was sitting next to gPhoto developer Marcus. Marcus was using darix’s Fuji camera to test integration into libgphoto, then the magic happened! Not only will some Fuji models be supported, but our community is growing larger. This is also a reminder that one person can make a huge difference. Thanks darix!

Welcome, gPhoto, and thank you for the years and years of development!

G'MIC 2.2

New features and filters!

The IMAGE team of the GREYC laboratory (UMR CNRS 6072, Caen, France) is pleased to announce the release of a new 2.2 version of G’MIC, its open-source, generic, and extensible framework for image processing. As we already did in the past, we take this opportunity to look at the latest notable features added since the previous major release (2.0, last June).

• The G’MIC project
• Twitter feed
• The G’MIC Online Web Service

Note 1: click on a picture to view a larger version. Note 2: This is a translation of an original article, in French, published on Linuxfr.

1. Context and recent evolutions

G’MIC is a free and open-source software developed since August 2008 (distributed under the CeCILL license), by folks in the IMAGE team at the GREYC, a French public research laboratory located in Caen and supervised by three institutions: the CNRS, the University of Caen, and the ENSICAEN engineering school. This team is made up of researchers and lecturers specialized in the fields of algorithms and mathematics for image processing. As one of the main developer of G’MIC, I wanted to sum up the work we’ve made on this software during these last months.

G’MIC is multi-platform (GNU/Linux, MacOS, Windows …) and provides many ways of manipulating generic image data, i.e. still images or image sequences acquired as hyperspectral 2D or 3D floating-point arrays (including usual color images). More than 950 different image processing functions are already available in the G’MIC framework, this number being expandable through the use of the G’MIC scripting capabilities.

Since the last major version release there have been two important events in the project life:

1.1. Port of the G’MIC-Qt plugin to Krita

When we released version 2.0 of G’MIC a few months ago, we were happy to announce a complete rewrite (in Qt) of the plugin code for GIMP. An extra step has been taken, since this plugin has been extended to fit into the open-source digital painting software Krita. This has been made possible thanks to the development work of Boudewijn Rempt (maintainer of Krita) and Sébastien Fourey (developer of the plugin). The G’MIC-Qt plugin is now available for Krita versions 3.3+ and, although it does not yet implement all the I/O functionality of its GIMP counterpart, the feedback we’ve had so far is rather positive. This new port replaces the old G’MIC plugin for Krita which has not been maintained for some time. The good news for Krita users (and developers) is that they now have an up-to-date plugin whose code is common with the one running in GIMP and for which we will be able to ensure the maintenance and further developments. Note this port required the writing of a source file host_krita.cpp (in C++) implementing the communication between the host software and the plugin, and it is reasonable to think that a similar effort would allow other programs to get their own version of the G’MIC plugin (and the 500 image filters that come with it!).

1.2. CeCILL-C, a more permissive license

Another major event concerns the new license of use : The CeCILL-C license (that is in the spirit of the LGPL) is now available for some components of the G’MIC framework. This license is more permissive than the previously proposed CeCILL license (which is GPL-compatible) and is more suitable for the distribution of software libraries. This license extension (now double licensing) applies precisely to the core files of G’MIC, i.e. its C++ library libgmic. Thus, the integration of the libgmic features (therefore, all G’MIC image filters) is now allowed in software that are not themselves licensed under GPL/CeCILL (including closed source products). The source code of the G’MIC-Qt plugin, meanwhile, remains distributed under the single CeCILL license (GPL-like).

2. Fruitful collaboration with David Revoy

If you’ve followed us for a while, you may have noticed that we very often refer to the work of illustrator David Revoy for his multiple contributions to G’MIC: mascot design, ideas of filters, articles or video tutorials, tests of all kinds, etc. More generally, David is a major contributor to the world of free digital art, as much with the comic Pepper & Carrot he produces (distributed under free license CC -BY), as with his suggestions and ongoing bug reports for the open-source software he uses. Therefore, it seems quite natural to devote a special section to him in this article, summarizing the different ideas, contributions and experiments he has brought to G’MIC just recently. A big thank you, David for your availability, the sharing of your ideas, and for all your work in general!

2.1. Improving the lineart colorization filter

Let’s first mention the progress made on the Black & White / Colorize lineart (smart-coloring) filter that had appeared at the time of the 2.0 G’MIC release. This filter is basically a lineart colorization assistant which was developed in collaboration with David. It tries to automatically generate a colorization layer for a given lineart, from the analysis of the contours and the geometry of that lineart. Following David‘s suggestions, we were able to add a new colorization mode, named “Autoclean“. The idea is to try to automatically “clean” a coloring layer (made roughly by the user) provided in addition to the lineart layer, using the same geometric analysis as for the previous colorization modes. The use of this new mode is illustrated below, where a given lineart (left) has been colorized approximately by the user. From the two layers line art + color layer, our “Autoclean“ algorithm generates an image (right), where the colors do not overflow the lineart contours (even for “virtual” contours that are not closed). The result is not always perfect, but nevertheless reduces the time spent in the tedious process of colorization.

Note that this filter is also equipped with a new hatch detection module, which makes it possible to avoid generating too many small areas when using the previously available random colorization mode, particularly when the input lineart contains a large number of hatches (see figure below).

2.2. Color equalizer in HSI, HSL and HSV spaces

More recently, David suggested the idea of a filter to separately vary the hue and saturation of colors having certain levels of luminosity. The underlying idea is to give the artist the ability to draw or paint digitally using only grayscale, then colorize his masterpiece afterwards by re-assigning specific colors to the different gray values of the image. The obtained result has of course a limited color range, but the overall color mood is already in place. The artist only has to retouch the colors locally rather than having to colorize the entire painting by hand. The figure below illustrates the use of this new filter Colors/Equalize HSI/HSL/HSV available in the G’MIC plugin : each category of values can be finely adjusted, resulting in preliminary colorizations of black and white paintings.

Note that the effect is equivalent to applying a color gradient to the different gray values of the image. This is something that could already be done quite easily in GIMP. But the main interest here is we can ensure that the pixel brightness remains unchanged during the color transformation, which is not an obvious property to preserve when using a gradient map. What is nice about this filter is that it can apply to color photographs as well. You can change the hue and saturation of colors with a certain brightness, with an effect that can sometimes be surprising, like with the landscape photography shown below.

2.3. Angular deformations

Another one of the David‘s ideas concerned the development of a random local deformation filter, having the ability to generate angular deformations. From an algorithmic point of view, it seemed relatively simple to achieve. Note that once the implementation has been done (in concise style: 12 lines!) and pushed into the official filter updates, David just had to press the “Update Filters“ button of his G’MIC-Qt plug-in, and the new effect Deformations/Crease was there immediately for testing. This is one of the practical side of developing new filters using the G’MIC script language!

However, I must admit I didn’t really have an idea on what this could be useful for in practice. But the good thing about cooperating with David is that HE knows exactly what he’s going to do with it! For instance, to give a crispy look to the edges of his comics, or for improving the render of his alien death ray.

3. Filters, filters, filters…

David Revoy is not the only user of G’MIC: we sometimes count up to 900 daily downloads from the main project website. So it happens, of course, that other enthusiastic users inspire us new effects, especially during those lovely discussions that take place on our forum, kindly made available by the PIXLS.US community.

3.1. Bring out the details without creating “halos”

Many photographers will tell you that it is not always easy to enhance the details in digital photographs without creating naughty artifacts that often have to be masked manually afterwards. Conventional contrast enhancement algorithms are most often based on increasing the local variance of pixel lightness, or on the equalization of their local histograms. Unfortunately, these operations are generally done by considering neighborhoods with a fixed size and geometry, where each pixel of a neighborhood is always considered with the same weight in the statistical calculations related to these algorithms. It is simpler and faster, but from a qualitative point of view it is not an excellent idea: we often get “halos” around contours that were already very contrasted in the image. This classic phenomenon is illustrated below with the application of the Unsharp mask filter (the one present by default in GIMP) on a part of a landscape image. This generates an undesirable “halo” effect at the frontier between the mountain and the sky (this is particularly visible in full resolution images).

The challenge of the detail enhancement algorithms is to be able to analyze the geometry of the local image structures in a more fine way, to take into account geometry-adaptive local weights for each pixel of a given neighborhood. To make it simple, we want to create anisotropic versions of the usual enhancement methods, orienting them by the edges detected in the images. Following this logic, we have added two new G’MIC filters recently, namely Details/Magic details and Details/Equalize local histograms, which try to better take the geometric content of the image into account for local detail enhancement (e.g. using the bilateral filter).

Thus, the application of the new G’MIC local histogram equalization on the landscape image shown before gives something slightly different : a more contrasted result both in geometric details and colors, and reduced halos.

3.2. Different types of image deformations

New filters to apply geometric deformations on images are added to G’MIC on a regular basis, and this new major version 2.2 offers therefore a bunch of new deformation filters. So let’s start with Deformations/Spherize, a filter which allows to locally distort an image to give the impression that it is projected on a 3D sphere or ellipsoid. This is the perfect filter to turn your obnoxious office colleague into a Mr. Potato Head!

On the other hand, the filter Deformations/Square to circle implements the direct and inverse transformations from a square domain (or rectangle) to a disk (as mathematically described on this page), which makes it possible to generate this type of deformations.

The effect Degradations/Streak replaces an image area masked by the user (filled with a constant color) with one or more copies of a neighboring area. It works mainly as the GIMP clone tool but prevents the user to fill the entire mask manually.

3.3. Artistic Abstractions

You might say that image deformations are nice, but sometimes you want to transform an image in a more radical way. Let’s introduce now the new effects that turn an image into a more abstract version (simplification and re-rendering). These filters have in common the analysis of the local image geometry, followed by a step of image synthesis.

For example, G’MIC filter Contours/Super-pixels locally gathers the image pixels with the same color to form a partitioned image, like a puzzle, with geometric shapes that stick to the contours. This partition is obtained using the SLIC method (Simple Linear Iterative Clustering), a classic image partitioning algorithm, which has the advantage of being relatively fast to compute.

The filter Artistic/Linify tries to redraw an input image by superimposing semi-transparent colored lines on an initially white canvas, as shown in the figure below. This effect is the re-implementation of the smart algorithm initially proposed on the site http://linify.me (initially implemented in JavaScript).

The effect Artistic/Quadtree variations first decomposes an image as a quadtree, then re-synthesize it by drawing oriented and plain ellipses on a canvas, one ellipse for each quadtree leaf. This renders a rather interesting “painting” effect. It is likely that with more complex shapes, even more attractive renderings could be synthesized. Surely an idea to keep in mind for the next filters update :)

3.4. “Are there any more?”

And now that you have processed so many beautiful pictures, why not arrange them in the form of a superb photo montage? This is precisely the role of the filter Arrays & tiles/Drawn montage, which allows to create a juxtaposition of photographs very quickly, for any kind of shapes. The idea is to provide the filter with a colored template in addition to the serie of photographs (Fig.3.10a), and then to associate each photograph with a different color of the template (Fig.3.10b). Next, the arrangement is done automatically by G’MIC, by resizing the images so that they appear best framed within the shapes defined in the given montage template (Fig.3.10c). We made a video tutorial illustrating the use of this specific filter.

But let’s go back to more essential questions: have you ever needed to draw gears? No?! It’s quite normal, that’s not something we do everyday! But just in case, the new G’MIC filter Rendering/Gear will be glad to help, with different settings to adjust gear size, colors and number of teeth. Perfectly useless, so totally indispensable!

Need a satin texture right now? No?! Too bad, the filter Patterns / Satin could have been of a great help!

And finally, to end up with the series of these “effects that are useless until we need them”, note the apparition of the new filter Degradations/JPEG artifacts which simulates the appearance of JPEG compression artifacts due to the quantization of the DCT coefficients encoding 8×8 image blocks (yes, you will get almost the same result saving your image as a JPEG file with the desired quality).

4. Other notable improvements

This review of these new available G’MIC filters should not overshadow the various improvements that have been made “under the hood” and that are equally important, even if they are less visible in practice for the user.

4.1. A better G’MIC-Qt plugin interface

A big effort of cleaning and restructuring the G’MIC-Qt plugin code has been realized, with a lot of little inconsistencies fixed in the GUI. Let’s also mention in bulk order some new interesting features that have appeared in the plugin:

• The ability to set a timeout) when trying to preview some computationnaly intensive filters.
• A better management of the input-output parameters for each filter (with persistence, better menu location, and a reset button).
• Maximizing the size of the preview area is now easier. Editing its zoom level manually is now possible, as well as chosing the language of the interface (regardless of the language used for the system), etc.

All these little things gathered together globally improves the user experience.

4.2. Improvements in the G’MIC core

Even less visible, but just as important, many improvements have appeared in the G’MIC computational core and its associated G’MIC script language interpreter. You have to know that all of the available filters are actually written in the form of scripts in the G’MIC language, and each small improvement brought to the interpreter may have a beneficial consequence for all filters at once. Without going too much into the technical details of these internal improvements, we can highlight those points:

• The notable improvement in the syntax of the language itself, which goes along with better performances for the analysis of the language syntax (therefore for the script executions), all this with a smaller memory footprint.

• The G’MIC built-in mathematical expression evaluator is also experiencing various optimizations and new features, to consider even more possibilities for performing non-trivial operations at the pixel level.

• A better support of raw video input/outputs (.yuv format) with support for4:2:2 and 4:4:4 formats, in addition to4:2:0 which was the only mode supported before.

• Finally, two new animations have been added to the G’MIC demos menu (which is displayed e.g. when invoking gmic without arguments from the command-line):

  • First, a 3D starfield animation:

  

  • Second, a playable 3D version of the Tower of Hanoi:

  

• Finally, let us mention the introduction of the command tensors3d dedicated to the 3D representation of second order tensor fields. In practice, it does not only serve to make you want to eat Smarties^®! It can be used for example to visualize certain regions of MRI volumes of diffusion tensors:

  

4.3. New design for G’MIC Online

To finish this tour, let us also mention the complete redesign of G’MIC Online during the year 2017, done by Christophe Couronne and Véronique Robert from the development departement of the GREYC laboratory. G’MIC Online is a web service allowing you to apply a subset of G’MIC filters on your images, directly inside a web browser. These web pages now have a responsive design, which makes them more enjoyable than before on mobile devices (smartphones and tablets). Shown below is a screenshot of this service running in Chrome/Android, on a 10’’ tablet.

5. Conclusion and perspectives

The overview of this new version 2.2 of G’MIC is now over. One possible conclusion could be: “There are plenty of perspectives!“.

G’MIC is a free project that can be considered as mature: the first lines of code were composed almost ten years ago, and today we have a good idea of the possibilities (and limits) of the beast. We hope to see more and more interest from FOSS users and developers, for example for integrating the G’MIC-Qt generic plugin in various software focused on image or video processing.

The possibility of using the G’MIC core under a more permissive CeCILL-C license can also be a source of interesting collaborations in the future (some companies have already approached us about this). While waiting for potential collaborations, we will do our best to continue developping G’MIC and feed it with new filters and effects, according to the suggestions of our enthusiastic users. A big thanks to them for their help and constant encouragement (the motivation to write code or articles, past 11pm, would not be the same without them!).

“Long live open-source image processing and artistic creation!”

LGM and Libre Graphics at SCaLE 16x

All the libre graphics!

There are two libre graphics related meetings coming up early next year. The annual Libre Graphics Meeting (in Spain this year), and something entirely new: a libre graphics track at SCaLE. How exciting!

Libre Graphics Meeting 2018

The Libre Graphics Meeting is going to be in Seville, Spain this year. They recently published their Call for Participation and are accepting presentation and talk proposals now. Unfortunately, I won’t be able to attend this year, but there’s a pretty good chance some friendlier folks from the community will be! We’ll update more about who will be making it out as soon as we know, and maybe we can convince someone to run another photowalk with everyone. (On a side note, if anyone from the community is going to make it and wants a hand putting anything together for a presentation just let us know - we’re here to help.)

Libre Graphics at SCaLE (California, USA)

This year we have a neat announcement - due to some prodding from Nate Willis, we have been given a day at the Southern California Linux Expo (SCaLE) to hold a Libre Graphics focused track! The expo is at the Pasadena Convention Center, March 8-11, 2018.

We first had a chance to hang out with LWN editor Nate Willis during the Libre Graphics Meeting 2016 in London, and later out at the Texas Linux Fest. GIMP was able to have both Akkana Peck and myself out to present on GIMPy stuff and host a photowalk as well.

The organizer for SCaLE, Ilan, was kind enough to give us a day (Friday, March 9^th) and a room for all the libre graphics artists, designers, programmers, and hackers.

I will be in attendance promoting GIMP stuff in the main track, Dr. Ullah (Isaac Ullah) will hopefully be presenting, and Mica will be there (@paperdigits) as well. I’m pretty certain we’ll be holding a photowalk for attendees while we’re there - and we may even setup a nice headshot booth in the expo to take free headshots for folks.

We would love to see some folks out there. If you think you might be able to make it, or even better submit a talk proposal, please come and join us! (I was thinking about getting an AirBnB to stay in, so if folks let me know they are going to make it out we can coordinate a place to all stay together.)

SCaLE Libre Graphics Track Call for Participation

The libre graphics community is thrilled to announce that a special, one-day track at SCaLE 16x will be dedicated to libre graphics software and artists. All those who work with free and open-source tools for creative graphics projects are invited to submit a proposal and join us for the day!

SCaLE 16x will take place from March 8 to 11 of 2018 in Pasadena California. Libre Graphics Day: SCaLE will take place at the main SCaLE venue on Friday, March 9.

The libre graphics track is an opportunity for teams, contributors and practitioners involved in Libre Graphics projects to share their experiences, showcase new developments, and hear new and inspiring ideas.

By libre graphics we mean “free, Libre and Open Source tools for creative uses”. Libre graphics is not just about software, but extends to standards and file formats used in creative work.

People from around the world who are passionate about Free/Libre tools and their creative applications are encouraged to submit a talk proposal. Sessions will be 30 minutes in length.

Developers, artists, and activists alike are invited. First-time presenters and established projects of all sizes are welcome to submit.

We are looking for:

• Reflections and practical sessions on promoting the philosophy and use of Libre Graphics tools.
• Technical presentations and workshops for developers.
• Showcases of excellent work made using Libre Graphics tools.
• New tools and workflows for graphics and code.
• Reflections on the activities of existing Free/Libre and Open Source communities.

Submit

Please submit your proposal to graphics-cfp@socallinuxexpo.org.

If you have any questions feel free to reach out to me on the forum.

Deadline

The deadline for submissions is January 10th, 2018, and participants will be notified by the end of January 2018.

Giving Thanks

For a wonderful community

This is becoming a sort of tradition for me to post something giving thanks around this holiday. I think it’s because this community has become such a large part of my life (even if I don’t have nearly as much time to spend on it as I’d like). Also, I think it helps to remind ourselves once in a while of the good things that happen to us. So in that spirit…

Financial Supporters

I want to start things off by acknowledging those that go the extra mile and help offset the costs of the infrastructure to keep this crazy ship afloat (sorry, I’m an ocean engineer by training and a sailor - so nautical metaphors abound!).

Holy Benefactors, Batman!

Once again the amazing Dimitrios Psychogios has graciously covered our server expenses (and then some) for another full year. On behalf of the community, and particularly myself, thank you so much! Your generosity will cover infrastructure costs for the year and give us room to grow as the community does.

We also have some awesome folks who support us through monthly donations (which are nice because we can plan better if we need to). Together they cover the costs of data storage + transfer in/out of Amazon AWS S3 storage (basically the storage and transfer of all of the attachments and files in the forums). So thank you, you cool froods, you really know where your towels are:

• Mica (@paperdigits - https://silentumbrella.com)
• Luka S.
• Barrie (@bminney)

Thank you all! If you happen to see any of these great folks around the forum consider taking a moment to thank them for their generosity! If you’d like to join them in supporting the site financially, check out the support page.

Growth

The community has just been amazing, and we’ve seen nice growth this past year. Since the end of August we’ve seen about a 50% increase in weekly sessions on discuss. We’re currently hovering around 2,500 daily pageviews on the forums:

We’ve added almost 950 new users, or almost 3 new users every day!

There have been quite a few interesting discussions happening on the forums as well. The RawTherapee folks have some neat conversations going on (Local Lab build, New Windows builds, and Pixel Shift!), and @Carmelo_DrRaw (creator of the PhotoFlow editor) has been packaging a GIMP 2.9.X AppImage as well!

Of course, the fun news for many was @houz finally pushing out a Windows version of darktable that was made possible through the help of Peter Budai.

raw.pixls.us

I figure @LebedevRI will yell at me if I forget to mention raw.pixls.us (RPU) again. Back in January @andabata built a new site to help pick up the work of the old rawsamples.ch website to collect raw sample files for testing.

So thank you @andabata and @LebedevRI for your work on this! A big thank you to everyone who has taken the time to check the site and upload missing (or non-freely licensed) raw files to include!

While we’re talking about RPU, please consider having a look at this post about it on discuss and take a few minutes to see if you might be able to contribute by providing raw samples that we are missing or need (see the post for more details). If you don’t have something we need, please consider sharing the post on social media to help us raise awareness of RPU! Thank you!

digiKam

If you’re not aware of it, one of the things we try to do here beside run the site and forum is to assist projects with websites and design work if they want it. Earlier this year the digiKam team needed to migrate their old Drupal website to something more modern (and secure) and @paperdigits figured, “why not”?

So we rolled up our sleeves and got them setup with a newly designed static website built using Hugo (which was completely new to me). We were also able to manage their comments on the website for them by embedding topics from right here on discuss. This way their users can still own their comments and we can manage spam and moderate things for them.

The best part, though, is the addition of their users and knowledge to the community!

darix

I want to personally take a moment to thank @darix for all the work he does keeping things running smoothly here. If you don’t see him, it means all the work he’s doing is paying off.

I speak with him daily and see firsthand the great work he’s doing to make sure all of us have a nice place to call home. Thank you so much, @darix!

Mica

As usual @paperdigits (https://silentumbrella.com) also has a great attitude and pro-active approach to the community which I am super thankful for. He also does things that aren’t always visible, but are essential to keeping things running smoothly, like moderating the forum, checking the health of sites we are helping to manage, and writing/editing posts.

I can’t stress enough how much it helps to keep your interest and spirits engaged in the community when you have someone else around who’s so positive and helpful. Thank you so much, @paperdigits!

All of You

At the end of the day this is a community, and it’s vibrancy and health is a direct result of all of you, its members. So above all else this is by far the thing I am most thankful for - getting to meet, learn, and interact with all of you.

Keep the Raws Coming

Moar samples!

Our friendly neighborhood @LebedevRI pointed out to me a little while ago that we had reached some nice milestones for https://raw.pixls.us. Not surprisingly I had spaced out and not written anything about it (or really any sort of social posts). Bad Pat!

So let’s talk about raw.pixls.us (RPU) a bit!

Recap

For anyone not familiar with RPU, a quick recap (we had previously written about raw.pixls.us earlier this year). There used to be a website for housing a repository of raw files for as many digital cameras as possible called rawsamples.ch. It was created by Jakob Rohrbach and had been running since March of 2007. Back in 2016 the site was hit with a SQL injection attack that left the Joomla database corrupted (in a teachable moment, the site also didn’t have a database backup).

With the rawsamples.ch site down, @LebedevRI and @andabata worked to get a replacement option in-place and working: https://raw.pixls.us!

Sexy Stats

We grabbed all the files we could salvage from rawsamples.ch and @andabata setup the new page. We’ve had a slowly growing response as folks have filled in gaps for camera models we still don’t have.

For reference, we currently have unique cameras, and unique samples.

Moar samples!

As @LebedevRI has said, we still really need folks to check RPU and send us more samples!

• We currently only have about 77% coverage.
• We want to replace any non-CC0 (public domain) samples with CC0 licensed samples.
• We are still missing some rarer samples like any medium-format or Sigma samples.

Our hope is that some casual reader out there might look at the list and say “Hey! I’ve got that camera lying around - let me submit a sample!”.

Here’s the current list of missing camera samples:

If you have any of the cameras on this list and don’t mind spending a few minutes uploading a sample file, we would be very grateful for the help!

Don’t forget that we are looking for:

• Lens mounted on the camera, cap off
• Image in focus and properly exposed
• Landscape orientation

and we are not looking for:

• Series of images with different ISO, aperture, shutter, wb, lighting, or different lenses
• DNG files created with Adobe DNG Converter
• Photographs of people, for legal reasons.

If you don’t see your camera on this list, you’re not off the hook yet! We are also looking for files that are licensed very freely…

Non Creative-Commons Zero (CC0)

We have many raw samples that were not licensed as freely as we would like. Ideally we are looking for images that have been released Creative Commons Zero (CC0). This list is all samples we already have that are not licensed CC0, so if you happen to have one of the cameras listed below please consider uploading some new samples for us!

We are really working hard to make sure we are a good resource of freely available raw samples for all Free Software imaging projects to use. Thank you so much for helping out if you can!

G'MIC 2.0

A second breath for open-source image processing.

The IMAGE team of the research laboratory GREYC in Caen/France is pleased to announce the release of a new major version (numbered 2.0) of its project G’MIC: a generic, extensible, and open source framework for image processing. Here, we present the main advances made in the software since our last article. The new features presented here include the work carried out over the last twelve months (versions 2.0.0 and 1.7.x, for _x_ varying from _2_ to _9_).

Links:

• G’MIC main project page
• Twitter feed
• G’MIC plug-in for GIMP
• G’MIC Online web service
• Changelog for the 2.0.0 version

1. G’MIC: A brief overview

G’MIC is an open-source project started in August 2008, by the IMAGE team. This French research team specializes in the fields of algorithms and mathematics for image processing. G’MIC is distributed under the CeCILL license (which is GPL compatible) and is available for multiple platforms (GNU/Linux, MacOS and Windows). It provides a variety of user interfaces for manipulating generic image data, that is to say, _2D_ or _3D_ multispectral images (or sequences) with floating-point pixel values. This includes, of course, “classic” color images.

The popularity of G’MIC mostly comes from the plug-in it provides for GIMP (since 2009). To date, there are more than 480 different filters and effects to apply to your images, which considerably enlarges the list of image processing filters available by default in GIMP.

G’MIC also provides a powerful and autonomous command-line interface, which is complementary to the CLI tools you can find in the famous ImageMagick or GraphicsMagick projects. There is also a web service G’MIC Online, allowing to apply image processing effects directly from a browser. Other (but less well known) G’MIC-based interfaces exist: a webcam streaming tool ZArt, a plug-in for Krita, a subset of filters available in Photoflow, Blender or Natron… All these interfaces are based on the CImg and libgmic libraries, that are portable, thread-safe and multi-threaded, via the use of OpenMP.

G’MIC has more than 950 different and configurable processing functions, for a library of only 6.5Mio, representing a bit more than 180 kloc. The processing functions cover a wide spectrum of the image processing field, offering algorithms for geometric manipulations, colorimetric changes, image filtering (denoising and detail enhancement by spectral, variational, non-local methods, etc.), motion estimation and registration, display of primitives (_2D_ or _3D_ mesh objects), edge detection, object segmentation, artistic rendering, etc. It is therefore a very generic tool for various uses, useful on the one hand for converting, visualizing and exploring image data, and on the other hand for designing complex image processing pipelines and algorithms (see these project slides for details).

2. A new versatile interface, based on Qt

One of the major new features of this version 2.0 is the re-implementation of the plug-in code, from scratch. The repository G’MIC-Qt developed by Sébastien (an experienced member of the team) is a _Qt_-based version of the plug-in interface, being as independent as possible of the widget API provided by GIMP.

This has several interesting consequences:

• The plug-in uses its own widgets (in _Qt_) which makes it possible to have a more flexible and customizable interface than with the GTK widgets used by the GIMP plug-in API: for instance, the preview window becomes resizable at will, manages zooming by mouse wheel, and can be freely moved to the left or to the right. A filter search engine by keywords has been added, as well as the possibility of choosing between a light or dark theme. The management of favorite filters has been also improved and the interface even offers a new mode for setting the visibility of the filters. Interface personalization is now a reality.

• The plug-in also defines its own API, which is used to facilitate its integration in third party software (other than GIMP). In practice, a software developer has to write a single file host_software.cpp implementing the functions of the API to make the link between the plug-in and the host application. Currently, the file host_gimp.cpp does this for GIMP as a host. But there is now also a stand-alone version available (file host_none.cpp that runs this _Qt_ interface in solo mode, from a shell (with command gmic_qt).

• Boudewijn Rempt, project manager and developer of the marvelous painting software Krita, has also started writing such a file host_krita.cpp to make this “new generation” plug-in communicate with Krita. In the long term, this should replace the previous G’MIC plug-in implementation they made (currently distributed with Krita), which is aging and poses maintenance problems for developers.

Minimizing the integration effort for developers, sharing the G’MIC plug-in code between different applications, and offering a user interface that is as comfortable as possible, have been the main objectives of this complete redesign. As you can imagine, this rewriting required a long and sustained effort, and we can only hope that this will raise interest among other software developers, where having a consistent set of image processing filters could be useful (a file host_blender.cpp available soon ? We can dream!). The animation below illustrates some of the features offered by this new _Qt_-based interface.

Note that the old plug-in code written in GTK was updated also to work with the new version 2.0 of G’MIC, but has fewer features and probably will not evolve anymore in the future, unlike the _Qt_ version.

3. Easing the work of cartoonists…

One of G’MIC’s purposes is to offer more filters and functions to process images. And that is precisely something where we have not relaxed our efforts, despite the number of filters already available in the previous versions!

In particular, this version comes with new and improved filters to ease the colorization of line-art. Indeed, we had the chance to host the artist David Revoy for a few days at the lab. David is well known to lovers of art and free software by his multiple contributions in these fields (in particular, his web comic Pepper & Carrot is a must-read!). In collaboration with David, we worked on the design of an original automatic line-art coloring filter, named Smart Coloring.

When drawing comics, the colorization of line-art is carried out in two successive steps: The original drawing in gray levels (Fig.3.2.[1]) is first pre-colored with solid areas, i.e. by assigning a unique color to each region or distinct object in the drawing (Fig.3.2.[3]). In a second step, the colourist reworks this pre-coloring, adding shadows, lights and modifying the colorimetric ambiance, in order to obtain the final colorization result (Fig.3.2.[4]). Practically, flat coloring results in the creation of a new layer that contains only piecewise constant color zones, thus forming a colored partition of the plane. This layer is then merged with the original line-art to get the colored rendering (merging both in multiplication mode, typically).

Artists admit it themselves: flat coloring is a long and tedious process, requiring patience and precision. Classical tools available in digital painting or image editing software do not make this task easy. For example, even most filling tools (bucket fill) do not handle discontinuities in drawn lines very well (Fig.3.3.a), and even worse when lines are anti-aliased. It is then common for the artist to perform flat coloring by painting the colors manually with a brush on a separate layer (Fig.3.3.b), with all the precision problems that this supposes (especially around the contour lines, Fig.3.3.c). See also this link for more details.

It may even happen that the artist decides to explicitly constrain his style of drawing, for instance by using aliased brushes in a higher resolution image, and/or by forcing himself to draw only connected contours, in order to ease the flat colorization work that has to be done afterwards.

The Smart Coloring filter developed in version 2.0 of G’MIC allows to automatically pre-color an input line-art without much work. First, it analyses the local geometry of the contour lines (estimating their normals and curvatures). Second, it (virtually) does contour auto-completion using spline curves. This virtual closure allows then the algorithm to fill objects with disconnected contour plots. Besides, this filter has the advantage of being quite fast to compute and gives coloring results of similar quality to more expensive optimization techniques used in some proprietary software. This algorithm smoothly manages anti-aliased contour lines, and has two modes of colorization: by random colors (Fig.3.2.[2] and Fig.3.4) or guided by color markers placed beforehand by the user (Fig.3.5).

In “random” mode, the filter generates a piecewise constant layer that is very easy to recolor with correct hues afterwards. This layer indeed contains only flat color regions, and the classic bucket fill tool is effective here to quickly reassign a coherent color to each existing region synthesized by the algorithm.

In the user-guided markers mode, color spots placed by the user are extrapolated in such a way that it respects the geometry of the original drawing as much as possible, taking into account the discontinuities in the pencil lines, as this is clearly illustrated by the figure below:

This innovative, flat coloring algorithm has been pre-published on HAL (in French): A semi-guided high-performance flat coloring algorithm for line-arts. Curious people could find there all the technical details of the algorithm used. The recurring discussions we had with David Revoy on the development of this filter enabled us to improve the algorithm step by step, until it became really usable in production. This method has been used successfully (and therefore validated) for the pre-colorization of the whole episode 22 of the webcomic Pepper & Carrot.

The wisest of you know that G’MIC already had a line-art colorization filter! True, but unfortunately it did not manage disconnected contour lines so well (such as the example in Fig.3.5), and could then require the user to place a large number of color spots to guide the algorithm properly. In practice, the performance of the new flat coloring algorithm is far superior.

And since it does not see any objection to anti-aliased lines, why not create ones? That is the purpose of another new filter “Repair / Smooth [antialias]“ able to add anti-aliasing to lines in cartoons that would have been originally drawn with aliased brushes.

4. …Not to forget the photographers!

“Colorizing drawings is nice, but my photos are already in color!”, kindly remarks the impatient photographer. Don’t be cruel! Many new filters related to the transformation and enhancement of photos have been also added in G’MIC 2.0. Let’s take a quick look of what we have.

4.1. CLUTs and colorimetric transformations

CLUTs (Color Lookup Tables) are functions for colorimetric transformations defined in the RGB cube: for each color (Rs,Gs,Bs) of a source image _Is_, a CLUT assigns a new color (Rd,Gd,Bd) transferred to the destination image _Id_ at the same position. These processing functions may be truly arbitrary, thus very different effects can be obtained according to the different CLUTs used. Photographers are therefore generally fond of them (especially since these CLUTs are also a good way to simulate the color rendering of certain old films).

In practice, a CLUT is stored as a _3D_ volumetric color image (possibly “unwrapped” along the z = B axis to get a _2D_ version). This may quickly become cumbersome when several hundreds of CLUTs have to be managed. Fortunately, G’MIC has a quite efficient CLUT compression algorithm (already mentioned in a previous article), which has been improved version after version. So it was finally in a quite relax atmosphere that we added more than 60 new CLUT-based transformations in G’MIC, for a total of 359 CLUTs usable, all stored in a data file that does exceed 1.2 Mio. By the way, let us thank Pat David, Marc Roovers and Stuart Sowerby for their contributions to these color transformations.

But what if you already have your own CLUT files and want to use them in GIMP? No problem ! The new filter “Film emulation / User-defined“ allows to apply such transformations from CLUT data file, with a partial support of files with extension .cube (CLUT file format proposed by Adobe, and encoded in ASCII o_O!).

And for the most demanding, who are not satisfied with the existing pre-defined CLUTs, we have designed a very versatile filter “Colors / Customize CLUT“, that allows the user to build their own custom CLUT from scratch: the user places colored keypoints in the RGB color cube and these markers are interpolated in _3D_ (according to a Delaunay triangulation) in order to rebuild a complete CLUT, i.e. a dense function in RGB. This is extremely flexible, as in the example below, where the filter has been used to change the colorimetric ambiance of a landscape, mainly altering the color of the sky. Of course, the synthesized CLUT can be saved as a file and reused later for other photographs, or even in other software supporting this type of color transformations (for example RawTherapee or Darktable).

To stay in the field of color manipulation, let us also mention the appearance of the filter “Colors / Retro fade“ which creates a “retro” rendering of an image with grain generated by successive averages of random quantizations of an input color image.

4.2. Making the details pop out

Many photographers are looking for ways to process their digital photographs so as to bring out the smallest details of their images, sometimes even to exaggeration, and we can find some of them in the pixls.us forum. Looking at how they perform allowed us to add several new filters for detail and contrast enhancement in G’MIC. In particular, we can mention the filters “Artistic / Illustration look“ and “Artistic / Highlight bloom“, which are direct re-implementations of the tutorials and scripts written by Sébastien Guyader as well as the filter “Light & Shadows / Pop shadows“ suggested by Morgan Hardwood. Being immersed in such a community of photographers and cool guys always gives opportunities to implement interesting new effects!

In the same vein, G’MIC gets its own implementation of the Multi-scale Retinex algorithm, something that was already present in GIMP, but here enriched with additional controls to improve the luminance consistency in images.

Our friend and great contributor to G’MIC, Jérome Boulanger, also implemented and added a dehazing filter “Details / Dcp dehaze“ to attenuate the fog effect in photographs, based on the Dark Channel Prior algorithm. Setting the parameters of this filter is kinda hard, but the filter gives sometimes spectacular results.

And to finish with this subsection, let us mention the implementation in G’MIC of the Rolling Guidance algorithm, a method to simplify images that has become a key step used in many newly added filters. This was especially the case in this quite cool filter for image sharpening, available in “Details / Sharpen [texture]“. This filter works in two successive steps: First, the image is separated into a texture component + a color component, then the details of the texture component only are enhanced before the image is recomposed. This approach makes it possible to highlight all the small details of an image, while minimizing the undesired halos near the contours, a recurring problem happening with more classical sharpening methods (such as the well known Unsharp Mask).

4.3. Masking by color

As you may know, a lot of photograph retouching techniques require the creation of one or several “masks”, that is, the isolation of specific areas of an image to receive differentiated processing. For example, the very common technique of luminosity masks is a way to treat differently shadows and highlights in an image. G’MIC 2.0 introduces a new interesting filter “Colors / Color mask [interactive]“ that implements a relatively sophisticated algorithm (albeit computationally demanding) to help creating complex masks. This filter asks the user to hover the mouse over a few pixels that are representative of the region to keep. The algorithm learns in real time the corresponding set of colors or luminosities and deduces then the set of pixels that composes the mask for the whole image (using Principal Component Analysis on the RGB samples).

Once the mask has been generated by the filter, the user can easily modify the corresponding pixels with any type of processing. The example below illustrates the use of this filter to drastically change the color of a car

It takes no more than a minute and a half to complete, as shown in the video below:

This other video exposes an identical technique to change the color of the sky in a landscape.

5. And for the others…

Since illustrators and photographers are now satisfied, let’s move on to some more exotic filters, recently added to G’MIC, with interesting outcomes!

5.1. Average and median of a series of images

Have you ever wondered how to easily estimate the average or median frame of a sequence of input images? The libre aficionado Pat David, creator of the site pixls.us often asked the question. First of all when he tried to denoise images by combining several shots of a same scene. Then he wanted to simulate a longer exposure time by averaging photographs taken successively. And finally, calculating averages of various kind of images for artistic purposes (for example, frames of music video clips, covers of Playboy magazine or celebrity portraits).

Hence, with his cooperation, we added new commands -median_files,-median_videos, -average_files and-average_videos to compute all these image features very easily using the CLI tool gmic. The example below shows the results obtained from a sub-sequence of the « Big Buck Bunny“ video. We have simply invoked the following commands from the Bash shell:

$ gmic -average_video bigbuckbunny.mp4 -normalize 0.255 -o average.jpg
$ gmic -median_video bigbuckbunny.mp4 -normalize 0.255 -o median.jpg

And to stay in the field of video processing, we can also mention the addition of the commands -morph_files and -morph_video that render temporal interpolations of video sequences, taking the estimated intra-frame object motion into account, thanks to a quite smart variational and multi-scale estimation algorithm.

The video below illustrates the rendering difference obtained for the retiming of a sequence using temporal interpolation, with (right) and without (left) motion estimation.

5.2. Deformations and “Glitch Art”

Those who like to mistreat their images aggressively will be delighted to learn that a bunch of new image deformation and degradation effects have appeared in G’MIC.

First of all, the filter “Deformations / Conformal maps“ allows one to distort an image using conformal maps. These deformations have the property of preserving the angles locally, and are most often expressed as functions of complex numbers. In addition to playing with predefined deformations, this filter allows budding mathematicians to experiment with their own complex formulas.

Fans of Glitch Art may also be concerned by several new filters whose rendering look like image encoding or compression artifacts. The effect “Degradations / Pixel sort“ sorts the pixels of a picture by row or by column according to different criteria and to possibly masked regions, as initially described on this page.

Degradations / /Pixel sort also has two little brothers, filters “Degradations / Flip & rotate blocks“ and “Degradations / Warp by intensity“. The first divides an image into blocks and allows to rotate or mirror them, potentially only for certain color characteristics (like hue or saturation, for instance).

The second locally deforms an image with more or less amplitude, according to its local geometry. Here again, this can lead to the generation of very strange images.

It should be noted that these filters were largely inspired by the Polyglitch plug-in, available for Paint.NET, and have been implemented after a suggestion from a friendly user (yes, yes, we try to listen to our most friendly users!).

5.3. Image simplification

What else do we have in store? A new image abstraction filter, Artistic / Sharp abstract, based on the Rolling Guidance algorithm mentioned before. This filter applies contour-preserving smoothing to an image, and its main consequence is to remove the texture. The figure below illustrates its use to generate several levels of abstraction of the same input image, at different smoothing scales.

In the same vein, G’MIC also gets a filter Artistic / Posterize which degrades an image to simulate posterization. Unlike the filter with same name available by default in GIMP (which mainly tries to reduce the number of colors, i.e. do color quantization), our version adds spatial simplification and filtering to approach a little more the rendering of old posters.

5.4. Other filters

If you still want more (and in this case one could say you are damn greedy!), we will end this section by discussing some of the new, but unclassifiable filters.

We start with the filter “Artistic / Diffusion tensors“, which displays a field of diffusion tensors, calculated from the structure tensors of an image (structure tensors are symmetric and positive definite matrices, classically used for estimating the local image geometry). To be quite honest, this feature had not been originally developed for an artistic purpose, but users of the plug-in came across it by chance and asked to make a GIMP filter from it. And yes, this is finally quite pretty, isn’t it?

From a technical point of view, this filter was actually an opportunity to introduce new drawing features into the G’MIC mathematical evaluator, and it has now become quite easy to develop G’MIC scripts for rendering custom visualizations of various image data. This is what has been done for instance, with the command -display_quiver reimplemented from scratch, and which allows to generate this type of rendering:

For lovers of textures, we can mention the apparition of two new fun effects: First, the “Patterns / Camouflage“ filter. As its name suggests, this filter produces a military camouflage texture.

Second, the filter “Patterns / Crystal background“ overlays several randomly colored polygons in order to synthesize a texture that vaguely looks like a crystal seen under a microscope. Pretty useful to quickly render colored image backgrounds.

And to end this long overview of new G’MIC filters developed since last year, let us mention “Rendering / Barnsley fern“. This filter renders the well-known Barnsley fern fractal. For curious people, note that the related algorithm is available on Rosetta Code, with even a code version written in the G’MIC script language, namely:

# Put this into a new file 'fern.gmic' and invoke it from the command line, like this:
# $ gmic fern.gmic -barnsley_fern
barnsley_fern :
  1024,2048
  -skip {"
      f1 = [ 0,0,0,0.16 ];           g1 = [ 0,0 ];
      f2 = [ 0.2,-0.26,0.23,0.22 ];  g2 = [ 0,1.6 ];
      f3 = [ -0.15,0.28,0.26,0.24 ]; g3 = [ 0,0.44 ];
      f4 = [ 0.85,0.04,-0.04,0.85 ]; g4 = [ 0,1.6 ];
      xy = [ 0,0 ];
      for (n = 0, n<2e6, ++n,
        r = u(100);
        xy = r<=1?((f1**xy)+=g1):
             r<=8?((f2**xy)+=g2):
             r<=15?((f3**xy)+=g3):
                   ((f4**xy)+=g4);
        uv = xy*200 + [ 480,0 ];
        uv[1] = h - uv[1];
        I(uv) = 0.7*I(uv) + 0.3*255;
      )"}
  -r 40%,40%,1,1,2

And here is the rendering generated by this function:

6. Overall project improvements

All filters presented throughout this article constitute only the visible part of the G’MIC iceberg. They are in fact the result of many developments and improvements made “under the hood”, i.e., directly on the code of the G’MIC script language interpreter. This interpreter defines the basic language used to write all G’MIC filters and commands available to users. Over the past year, a lot of work has been done to improve the performances and the capabilities of this interpreter:

• The mathematical expressions evaluator has been considerably enriched and optimized, with more functions available (especially for matrix calculus), the support of strings, the introduction of const variables for faster evaluation, the ability to write variadic macros, to allocate dynamic buffers, and so on.

• New optimizations have been also introduced in the CImg library, including the parallelization of new functions (via the use of OpenMP). This C++ library provides the implementations of the “critical” image processing algorithms and its optimization has a direct impact on the performance of G’MIC (in this respect, note that CImg is also released with a major version 2.0).

• Compiling G’MIC on Windows now uses a more recent version of g++ (6.2 rather than 4.5), with the help of Sylvie Alexandre. This has actually a huge impact on the performances of the compiled executables: some filters run up to 60 times faster than with the previous binaries (this is the case for example, with the Deformations / Conformal Maps filter, discussed in section 5.2).

• The support of large .tiff images (format BigTIFF, with files that can be larger than 4Gb) is now enabled (read and write), as it is for 64-bit floating-point TIFF images

• The 3D rendering engine built into G’MIC has also been slightly improved, with the support for bump mapping. No filter currently uses this feature, but we never know, and prepare ourselves for the future!

• And as it is always good to relax after a hard day’s work, we added the game of Connect Four to G’MIC :). It can be launched via the shell command $ gmic -x_connect4 or via the plug-in filter “Various / Games & demos / Connect-4“. Note that it is even possible to play against the computer, which has a decent but not unbeatable skill (the very simple _AI_ uses the Minimax algorithm with a two-level decision tree).

Finally, let us mention the undergoing redesign work of the G’MIC Online web service, with a beta version already available for testing. This re-development of the site, done by Christophe Couronne and Véronique Robert (both members of the GREYC laboratory), has been designed to better adapt to mobile devices. The first tests are more than encouraging. Feel free to experiment and share your impressions!

7. What to remember?

First, the version 2.0 of G’MIC is clearly an important step in the project life, and the recent improvements are promising for the future developments. It seems that the number of users are increasing (and they are apparently satisfied!), and we hope that this will encourage open-source software developers to integrate our new G’MIC-Qt interface as a plug-in for their own software. In particular, we are hopeful to see the new G’MIC in action under Krita soon, this would be already a great step!

Second, G’MIC continues to be an active project, and evolve through meetings and discussions with members of artists and photographers communities (particularly those who populate the forums and IRC of pixls.us and GimpChat). You will likely able to find us there if you need more information, or just if you want to discuss things related to (open-source) image processing.

And while waiting for a future hypothetical article about a future release of G’MIC, you can always follow the day-after-day progress of the project via our Twitter feed.

Until then, long live open-source image processing!

Credit: Unless explicitly stated, the various non-synthetic images that illustrate this post come from Pixabay.

Happy 2nd Birthday Discuss

Time keeps on slippin'

I was idling in our IRC chat room earlier when @Morgan_Hardwood wished us all a “Happy Discuss Anniversary”. Wouldn’t you know it, another year slipped right by! (Surely there’s no way it could already be a year since the last birthday post? Where does the time go?)

We’ve had a bunch of neat things happen in the community over the past year! Let’s look at some of the highlights.

Support

I want to start with this topic because it’s the perfect opportunity to recognize some folks who have been supporting the community financially…

When I started all of this I decided that I definitely didn’t want ads to be on the site anywhere. I had gotten enough donations from my old blog and GIMP tutorials that I could cover costs for a while entirely from those funds (I also re-did my personal blog recently and removed all ads from there as well).

I don’t like ads. You don’t like ads. We’re a big enough community that we can keep things going without having to bring those crappy things into our lives. So to reiterate, we’re not going to run ads on the site.

We are hosting the main website on Stablehost, the forums (discuss) are on a VPS at Digital Ocean, and our file storage for discuss is out on Amazon S3(see below). All told our costs are about $30 per month. Not so bad!

Thank You!

Even so, we have had some folks who have donated to help us offset these costs and I want to take a moment to recognize their generosity and graciousness!

Dimitrios Psychogios has been a supporter of the site since the beginning. This past year he covered (more than) our hosting costs for the entire year, and for that I am infinitely grateful (yes, I have infinite gratitude). It also helps that based on his postings on G+ our musical tastes are very similarly aligned. As soon as I get the supporters page up you’re going to the top of the list! Thank you, Dimitrios, for your support of the community!

Jonas Wagner (@Jonas_Wagner) and McCap (@McCap) both donated this past year as well. Which is doubly-awesome because they are both active in the community and have written some great content for everyone as well (@McCap is the author of the article A Masashi Wakui look with GIMP, and has been active in the community since the beginning as well).

Mica (@paperdigits) and Luka are both recurring donators which I am particularly grateful for. It really helps for planning to know we have some recurring support like that.

I have a bunch of donations where the donators didn’t leave me a name to use for attribution and I don’t want to just assume it’s ok. If you know you donated and see your first name in the list below (and are ok with me using your full name and a link if you want) then please let me know and I’ll update this post (and for the donators page later).

These are the folks who are really making a difference by taking the time and being gracious enough to support us. Even if you don’t want your full name out here, I know who you are and am very, very grateful and humbled by your generosity and kindness. Thank you all so much!

• Marc W. (you rock!)
• Ulrich P.
• Luc V.
• Ben E.
• Keith A.
• Philipp H.
• Christian M.
• Matthieu M.
• Christian M.
• Christian K.
• Maria J.
• Kevin P.
• Maciej D.
• Christian K.
• Egbert G.
• Michael H.
• Jörn H.
• Boris H.
• Norman S.
• David O.
• Walfrido C.
• Philip S.
• David S.
• Keith B.
• Andrea V.
• Stephan R.
• David M.
• Bastian H.
• Chance J.
• Luka S.
• Nathanael S.
• Sven K.
• Pepijn V.
• Benjamin W.
• Jörg W.
• Patrick B.
• Joop K.
• Alain V.
• Egor S.
• Samuel S.

On that note. If anyone wanted to join the folks above in supporting what we’re up to, we have a page specifically for that:

https://pixls.us/support/

Remember, no amount is too small!

Libre Graphics Meeting Rio

I wasn’t able to attend LGM this year, being held down in Rio (but the GIMP team did). That’s not to say that we didn’t have folks from the community there: Farid (@frd) from Estúdio Gunga was there!

I was able to help coordinate a presentation by Robin Mills (@clanmills) about the state (and future) of Exiv2. They’re looking for a maintainer to join the project, as Robin will be stepping down at the end of the year for studies. If you think you’d be interested in helping out, please get in touch with Robin on the forums and let him know!

I also put together (quickly) a few slides on the community that were included in the “State of the Libre Graphics” presentation that kicks off the meeting (presented this year by GIMPer Simon Budig):

This was just a short overview of the community and I think it makes sense to include it here was well. Since we stood the forum up two years ago we’ve seen about 3.2 million pageviews and have just under 1,400 users in the community. Which is just awesome to me.

@LebedevRI was also going to be mad if I didn’t take the time to at least let folks know about raw.pixls.us, where we currently have 693 raw files across 477 cameras. Please, take a moment to check raw.pixls.us and see if we are missing (or need better) files from a camera you may have, and get us samples for testing!

raw.pixls.us

We set up raw.pixls.us so we can gather camera raw samples for regression testing of rawspeed as well to have a place for any other project that might need raw files to test with. As we blogged about previously, the new site is also a replacement for the now defunct rawsamples.ch website.

Stop in and see if we’re missing a sample you can provide, or if you can provide a better (or better licensed) version for your camera. We’re focusing specifically on CC0 contributions.

Welcome digiKam!

As I mentioned in my last blog post, we learned that the digiKam team was looking for a new webmaster through a post on discuss. @Andrius posted a heads up on the digiKam 5.5.0 release in this thread.

Needless to say, less than a month or so later, @paperdigits had already finished up a nice new website for them! This is something we’re really trying to help out the community with and are super glad to be able to help out the digiKam team with this. The less time they have to worry about web infrastructure and security for it, the more time they can spend on awesome new features for their project and users.

Yes, we used a static site generator (Hugo in this case), and we were also able to move their commenting system to use discuss as its back-end! This is the same way we’re doing comments for PIXLS.US right now (scroll to the bottom of this post).

They’ve got their own category on discuss for both general digiKam discussion as well as their linked comments from their website.

Speaking of using discourse as a commenting system…

Discourse upstream

We’ve been using discourse as our forum software from the beginning. It’s a modern, open, and full-featured forum software that I think works incredibly well as a modern web application.

The ability to embed comments in a website that are part of the forum was one of the main reasons I went with it. I didn’t want to expose users to unnecessary privacy concerns by embedding a third-party commenting system (cough, disqus, cough). If I was going to go through the trouble of setting up a way to comment on things, I wanted to homogenize it with a full community-building effort.

This past year they (the discourse devs) added the ability to embed comments in multiple hosts (it was only one host when we first stood things up). This means that we can now manage the comments for anyone else thay may need them! Of course, building out a new website for digiKam meant that this was a perfect time to test things.

It all works beautifully, with one minor nitpick. The ability to style the embedded comments was limited to a single style for all the places that they might be embedded. This may be fine if all of the sites look similar, but if you visit www.digikam.org and compare it to here, you can see they are a little bit different… (we’re on white, digikam.org is on a dark background).

We needed a way to isolate the styling on a per-host basis, which after much help from @darix (yet again :)) I was able to finally hack something together that worked and get it pushed upstream (and merged finally)!

Play Raw

When RawTherapee migrated their official forums over to pixls they brought something really fun with them: Play Raw. They would share a single raw file amongst the community and then have everyone process and share their results (including their processing steps and associated .pp3 settings file).

If you haven’t seen it yet, we’ve had quite a few Play Raw posts over the past year with all sorts of wonderful images to practice on and share! There are portraits, children, dogs, cats, landscapes, HDR, and phở! There’s over 19 different raw files being shared right now, so come try your hand at processing (or even share a file of your own)!

The full list of play_raw posts can always be found here:
https://discuss.pixls.us/tags/play_raw

Amazon S3

We are a photography forum, so it only made sense that we made it as easy as possible for community members to upload and share images (raw files, and more). It’s one of the things I love about discourse that it’s so easy to add these things to your posts (simply drag-and-drop into the post editor) and upload them.

While this is easy to do, it does mean that we have to store all of this data. The VPS we use from Digital Ocean only has a 40GB SSD and it has to include all of the main forum running on it. We did have a little space for a while, but to help alleviate the local storage as a possible problem down the line, I moved our file storage out to Amazon S3.

This means that we can upload all we want and won’t really hit a wall with actual available storage space. It costs more each month than trying to store it all on local storage for the site, but then we don’t have to worry about expansion (or migration) later. Plus our current upload size limit per file is 100MB!

As you can see, we’re only looking at about $5USD/month on average in storage and transfer costs for the site with Amazon.

We’re also averaging about $22usd/month in hosting costs with Digital Ocean, so we’re still only about $27/month in total hosting costs. Maybe $30 if we include the hosting for the main website which is at Stablehost.

IRC

We’ve had an IRC room for a long time (longer than discuss I think), but I only just got around to including a link on the site for folks to be able to join through a nice web client (Kiwi IRC).

It was included as part of an oft-requested set of links to get back to various parts of the main site from the forums. I also added these links in the menu for the site as well (the header links are hidden when on mobile, so this way you can still access the links from whatever device you’re using):

If you have your own IRC client then you can reach us on irc.freenode.net #pixls.us. Come and join us in the chat room! If you’re not there you are definitely missing out on a ton of stimulating conversation and enlightening discussions!

Welcome digiKam!

Lending a helping hand

One of the goals we have here at PIXLS.US is to help Free Software projects however we can, and one of those ways is to focus on things that we can do well that might help make things easier for the projects. It may not be much fun for project developers to deal with websites or community outreach necessarily. This is something I think we can help with, and recently we had an opportunity to do just that with the awesome folks over at the photo management project digiKam.

As part of a post announcing the release of digiKam 5.5.0 on discuss. we learned that they were in need of a new webmaster, and they needed something soon to migrate away from Drupal 6 for security reasons. They had a rudimentary Drupal 7 theme setup, but it was severely lacking (non-responsive and not adapted to the existing content).

Mica (@paperdigits) reached out to Gilles Caulier and the digiKam community and offered our help, which they accepted! At that point Mica gathered requirements from them and found in the end that a static website would be more than sufficient for their needs. We coordinated with the KDE folks to get a git repo setup for the new website, and rolled up our sleeves to start building!

Mica chose to use the Hugo static-site generator to build the site with. This was something new for us, but turned out to be quite fast and fun to work with (it generates the entire digiKam site in just about 5 seconds). Coupled with a version of the Foundation 6 blog theme we were able to get a base site framework up and running fairly quickly. We scraped all of the old site content to make sure that we could port everything as well as make sure we didn’t break any urls along the way.

We iterated some design stuff along the way, ported all of the old posts to markdown files, hacked at the theme a bit, and finally included comments that are now hosted on discuss. What’s wild is that we managed to pull the entire thing together in about 6 weeks total (of part-time working on it). The digiKam team seems happy with the results so far, and we’re looking forward to continue helping them by managing this infrastructure for them.

A big kudos to Mica for driving the new site and getting everything up and running. This was really all due to his hard work and drive.

Also, speaking of discuss, we also have a new category created specifically for digiKam users and hackers: https://discuss.pixls.us/c/software/digikam.

This is the same category that news posts from the website will post in, so feel free to drop in and say hello or share some neat things you may be working on with digiKam!

GIMP is Going to LGM!

Tall and tan and young and lovely...

This years Libre Graphics Meeting (2017) is going to be held in the lovely city seen above, Rio de Janeiro, Brazil! This is an important meeting for so many people in the Free/Libre art community as it’s one of the only times they have an opportunity to meet face to face.

We’ve had some folks attending the past LGM’s (Leipzig and London) and it’s a wonderful opportunity to spend some time with friends. (Also, @frd from the community will be there!)

So in the spirit of camaraderie, I have a request…

Donate

The GIMP team will be in attendance this year. I happen to have a fondness for them so I’m asking anyone reading this to please head over and donate to the project.

That link is for the GNOME PayPal account, but there are other ways to donate as well.

This is one of the few times that the GIMP team gets a chance to meet in person. They use the time to hack at GIMP and to manage internal business. The time they get to spend together is invaluable to the project and by extension everyone that uses GIMP.

Just look at these faces! Surely this (Brady) Bunch of folks is worth helping to get a better GIMP?

Attending

Besides @frd I’m not sure who else from the community might be attending, so if I’ve missed you I apologize! Please feel free to use this topic to communicate and coordinate if you’d like.

It appears that personally I’m on a biennial schedule with attending LGM - so I’m looking forward to next year to be able to catch up with everyone!

Find us at SCaLE 15x

The Southern California Linux Expo (SCaLE) 15x is returning to the Pasadena Convention Center on March 2-5, 2017. SCaLE is one of the largest community-organized conferences in North America, with some 3,500 attendees last year.

If you’re attending the conference this year, find me, @paperdigits and lets talk shop or grab a meal!

From the Community Vol. 2

Welcome to the second installment of From the Community, a (hopefully) quarterly-ish blog post to highlight a few of the things our community members have been doing!

Improving grain simulation

@arctic has posted some research about how to better simulate grain in our digital images and the ensuing conversation is both fascinating and way above my head! This discussion is thus far raw processor independent and more input and code is welcome!

A tutorial on RBG color mixing

We’ve somewhat recently welcomed the painters into the fold on the pixls’ forum and @Elle rewarded us all with a tutorial RGB color mixing. She delves into subjects such as mixing color pigments like a traditional painter and how to handle that in the digital darkroom. You can read the whole article here.

Working to support Pentax Pixel Shift files in RawTherapee

There has been a lot of on-going work to bring support for Pentax Pixel Shift files in RawTherapee; the thread has now reached 234 posts and it is inspiring to see the community and developers coming together to bring support for an interesting technology. The feature set has been evolving pretty rapidly and it will be exiting when it makes it to a stable release.

Midi controller support for Darktable

Some preliminary work has begun to bring generic midi controller support to darktable. The funding for the midi controller to spur the development of this feature is a direct result of the members of the forum directly giving to further community causes. Once the darktable developers are finished with the midi controller, it’ll be offered to other developers to use to help implement support!

Methods for dealing with clipped highlights

@Morgan_Hardwood has written a very nice post detailing several methods for dealing with clipped highlights in RawTherapee. These include tone-mapping, highlights and shadows, and using the CIECAM02 mode.

New Year, New Raw Samples Website

A replacement for rawsamples.ch

Happy New Year, and I hope everyone has had a wonderful holiday!

We’ve been busy working on various things ourselves, including migrating RawPedia to a new server as well as building a replacement raw sample database/website to alleviate the problems that rawsamples.ch was having…

rawsamples.ch Replacement

Rawsamples.ch is a website with the goal to:

…provide RAW-Files of nearly all available Digitalcameras mainly to software-developers. [sic]

It was created by Jakob Rohrbach and had been running since March 2007, having amassed over 360 raw files in that time from various manufacturers and cameras. Unfortunately, back in 2016 the site was hit with a SQL-injection that ended up corrupting the database for the Joomla install that hosted the site. To compound the pain, there were no database backups… :(

On the good side, the PIXLS.US community has some dangerous folks with idle hands. Our friendly, neighborhood @andabata (Kees Guequierre) had some time off at the end of the year and a desire to build something. You may know @andabata as the fellow responsible for the super-useful dtstyle website, which is chock full of darktable styles to peruse and download (if you haven’t heard of it before – you’re welcome!). He’s also my go-to for macro photography and is responsible for this awesome image used on a slide for the Libre Graphics Meeting:

Luckily, he decided to build a site where contributors could upload sample raw files from their cameras for everyone to use – particularly developers. We downloaded the archive of the raw files kept at rawsamples.ch to include with files that we already had. The biggest difference between the files from rawsamples.ch and raw.pixls.us is the licensing. The existing files, and the preference for any new contributions, are licensed as Creative Commons Zero - Public Domain (as opposed to CC-BY-NC-SA).

After some hacking, with input and guidance from darktable developer Roman Lebedev, the site was finally ready. The repository for it can be found on GitHub: raw.pixls.us repo.

raw.pixls.us

The site is now live at https://raw.pixls.us.

You can look at the submitted files and search/sort through all of them (and download the ones you want).

In addition to browsing the archive, it would be fantastic if you were able to supplement the database by uploading sample images. Many of the files from the rawsamples.ch archive are licensed CC-BY-NC-SA, but we’d rather have the files licensed Creative Commons Zero - Public Domain. CC0 is preferable because if the sample raw files are separated from the database, they can safely be redistributed without attribution. So if you have a camera that is already in the list with the more restrictive license, then please consider uploading a replacement for us!

We are looking for shots that are:

• Lens mounted on the camera
• Lens cap off
• In focus
• Properly exposed (not over/under)
• Landscape orientation
• Licensed under the Creative Commons Zero

We are not looking for:

• Series of images with different ISO, aperture, shutter, wb, or lighting
  (Even if it’s a shot of a color target)
• DNG files created with Adobe DNG Converter

Please take a moment and see if you can provide samples to help the developers!

Welcome Digital Painters

You mean there's art outside photography?

Yes, there really is art outside photography. :)

The history and evolution of painting has undergone a similar transformation as most things adapting to a digital age. As photographers, we adapted techniques and tools commonly used in the darkroom to software, and found new ways to extend what was possible to help us achieve a vision. Just as we tried to adapt skills to a new environment, so too did traditional artists, like painters.

These artists adapted by not only emulating the results of various techniques, but by pushing forward the boundaries of what was possible through these new (Free Software) tools.

Impetus

Digital painting discussions with Free Software lacks a good outlet for collaboration that can open the discussion for others to learn from and participate in. This is a similar situation the Free Software + photography world was in that prompted the creation of pixls.us.

Due to this, both Americo Gobbo and Elle Stone reached out to us to see if we could create a new category in the community about Digital Painting with a focus on promoting serious discussion around techniques, processes, and associated tools.

Both of them have been working hard on advancing the capabilities and quality of various Free Software tools for years now. Americo brings with him the interest of other painters who want to help accelerate the growth and adoption of Free Software projects for painting (and more) in a high-quality and professional capacity. A little background about them:

Americo Gobbo studied Fine Arts in Bologna, Italy. Today he lives and works in Brazil, where he continues to develop studies and create experimentation with painting and drawing mainly within the digital medium in which he tries to replicate the traditional effects and techniques from the real world to the virtual.

Elle Stone is an amateur photographer with a long-standing interest in the history of photography and print making, and in combining painting and photography. She’s been contributing to GIMP development since 2012, mostly in the areas of color management and proper color mixing and blending.

Artists

With this introductory post to the new Digital painting category forum we feature Gustavo Deveze, who is a Visual Artist using free software. Deveze’s work is characterized by mixing different medias and techniques. With future posts we want to continue featuring artists using free software.

Gustavo Deveze

Gustavo Deveze is a visual artist and lives in Buenos Aires. He trained as a draftsman at the National School of Fine Arts “Manuel Belgrano”, and filmmaker at IDAC - Instituto de Arte Cinematográfica in Avellaneda, Argentina.

His works utilize different materials and supports and he is published by different publishers. Although in the last years he works mainly in digital format and with free software. He has participated in national and international shows and exhibitions of graphics and cinema with many awards. His last exposition can be seen on issuu.com: https://issuu.com/gustavodeveze/docs/inadecuado2edicion

Website: http://www.deveze.com.ar

• Blog: http://jeneverito.blogspot.com.ar/
• Google+: https://plus.google.com/107589083968107443043
• Facebook: https://www.facebook.com/gustavo.deveze

Digital Painting Category

The new Digital Painting category is for discussing painting techniques, processes, and associated tools in a digital environment using Free/Libre software. Some relevant topics might include:

• Emulating non-digital art, drawing on diverse historical and cultural genres and styles of art.

• Emulating traditional “wet darkroom” photography, drawing on the rich history of photographic and printmaking techniques.

• Exploring ways of making images that were difficult or impossible before the advent of new algorithms and fast computers to run them on, including averaging over large collections of images.

• Discussion of topics that transcend “just photography” or “just painting”, such as composition, creating a sense of volume or distance, depicting or emphasizing light and shadow, color mixing, color management, and so forth.

• Combining painting and photography: Long before digital image editing artists already used photographs as aids to and part of making paintings and illustrations, and photographers incorporated painting techniques into their photographic processing and printmaking.

• An important goal is also to encourage artists to submit tutorials and videos about Digital Painting with Free Software and to also submit high-quality finished works.

Say Hello!

Please feel free to stop into the new [Digital Painting category][dp-forum], introduce yourself, and say hello! I look forward to seeing what our fellow artists are up to.

All images not otherwise specified are licensed [CC-BY-NC-SA][] [CC-BY-NC-SA]: https://creativecommons.org/licenses/by-nc-sa/4.0/ [dp-forum]: https://discuss.pixls.us/c/digital-painting

Giving Thanks

For an awesome community!

Here in the U.S., we have a big holiday coming up this week: Thanksgiving. Serendipitously, this holiday also happens to fall when a few neat things are happening around the community, and what better time is there to recognize some folks and to give thanks of our own? No time like the present!

A Special Thanks

I feel a special “Thank You” should first go to a photographer and fantastic supporter of the community, Dimitrios Psychogios. Last year for our trip to Libre Graphics Meeting, London he stepped up with an awesome donation to help us bring some fun folks together.

This year he was incredibly kind by offering a donation to the community (completely unsolicited) that covers our hosting and infrastructure costs for an entire year! So on behalf of the community, Thank You for your support, Dimitrios!

I’ll be creating a page soon that will list our supporters as a means of showing our gratitude. Speaking of supporters and a new page on the site…

A Support Page

Someone had asked about the possibility of donating to the community on a post. We were talking about providing support in darktable for using a midi controller deck and the costs for some of the options weren’t too extravagant. This got us thinking that enough small donations could probably cover something like this pretty easily, and if it was community hardware we could make sure it got passed around to each of the projects that would be interested in creating support for it.

That conversation had me thinking about ways to allow folks to support the community. In particular, ways to make it easy to provide support on an on-going basis if possible (in addition to simple, single donations). There are goal-oriented options out there that folks are probably already familiar with (Kickstarter, Indiegogo and others) but the model for us is less goal-oriented and more about continuous support.

Patreon was an option as well (and I already had a skeleton Patreon account set up), but the fees were just too much in the end. They wanted a flat 5% along with the regular PayPal fees. The general consensus among the staff was that we wanted to maximize the funds getting to the community.

The best option in the end was to create a merchant account on PayPal and manually set up the various payment options. I’ve set them up similar to how a service like Patreon might run with four different recurring funding levels and an option for a single one-time payment of whatever a user would like. Recurring levels are nice because they make it easier to plan with.

We’re Not Asking

Our requirements for the infrastructure of the site are modest and we haven’t actively pursued support or donations for the site before. That hasn’t changed.

We’re not asking for support now. The best way that someone can help the community is by being an active part of it.

Engaging others, sharing what you’ve done or learned, and helping other users out wherever you can. This is the best way to support the community.

I purposely didn’t talk about funding before because I don’t want folks to have to worry or think about it. And before you ask: no, we are not and will not run any advertising on the site. I’d honestly rather just keep paying for things out of my pocket instead.

We’re not asking for support, but we’ll accept it.

With that being said, I understand that there’s still some folks that would like to contribute to the infrastructure or help us to get hardware to add support in projects and more. So if you do want to contribute, the page for doing so can be found here:

https://pixls.us/support

There are four recurring funding levels of $1, $3, $5, and $10 per month. There is also a one-time contribution option as well.

We also have an Amazon Affiliate link option. If you’re not familiar with it, you simply click the link to go to Amazon.com. Then anything you buy for the next 24 hours will give us some small percentage of your purchase price. It doesn’t affect the price of what you’re buying at all. So if you were going to purchase something from Amazon anyway, and don’t mind - then by all means use our link first to help out!

1000 Users

This week we also finally hit 1,000 users registered on discuss! Which is just bananas to me. I am super thankful for each and every member of the community that has taken the time to participate, share, and generally make one of the better parts of my day catching up on what’s been going on. You all rock!

While we’re talking about a number “1” with bunch of zeros after it, we recently made some neat improvements to the forums…

100 Megabytes

We are a photography community and it seemed stupid to have to restrict users from uploading full quality images or raw files. Previously it was a concern because the server the forums are hosted on have limited disk space (40GB). Luckily, Discourse has an option for storing all uploads to the forum on Amazon S3 buckets.

I went ahead and created some S3 buckets so that any uploads to the forums will now be hosted on Amazon instead of taking up precious space on the server. The costs are quite reasonable (around $0.30/GB right now), and it also means that I’ve been able to bump the upload size to 100MB for forum posts! You can now just drag and drop full resolution raw files directly into the post editor to include the file!

Travis CI Automation

On a slightly geekier note, did you know that the code for the entire website is available on Github? It’s also licensed liberally (CC-BY-SA), so no reason not to come and fiddle with things with us! One of the features of using Github is integration with Travis CI (Continuous Integration).

What this basically means is that every commit to the Github repo for the website gets picked up by Travis and built to test that everything is working ok. You can actually see the history of the website builds there.

I’ve now got it set up so that when a build is successful on Travis, it will automatically publish the results to the main webserver and make it live. Our build system, Metalsmith, is a static site generator. This means that we build the entire website on our local computers when we make changes, and then publish all of those changes to the webserver. This change automates that process for us now by handling the building and publishing if everything is ok.

In fact, if everything is working the way I think it should, this very blog post will be the first one published using the new automated system! Hooray!

You can poke me or @paperdigits on discuss if you want more details or feel like playing with the website.

Mica

Speaking of @paperdigits, I want to close this blog post with a great big “Thank You!“ to him as well. He’s the only other person insane enough to try and make sense of all the stuff I’ve done building the site so far, and he’s been extremely helpful hacking at the website code, writing articles, make good infrastructure suggestions, taking the initiative on things (t-shirts and github repos), and generally being awesome all around.

João Almeida's darktable Presets

A gorgeous set of film emulation for darktable

I realize that I’m a little late to this, but photographer João Almeida has created a wonderful set of film emulation presets for darktable that he uses in his own workflow for personal and commisioned work. Even more wonderful is that he has graciously released them for everyone to use.

These film emulations started as a personal side project for João, and he adds a disclaimer to them that he did not optimize them all for each brand or model of his cameras. His end goal was for these to be as simple as possible by using a few darktable modules. He describes it best on his blog post about them:

The end goal of these presets is to be as simple as possible by using few Darktable modules, it works solely by manipulating Lab Tone Curves for color manipulation, black & white films rely heavily on Channel Mixer. Since I what I was aiming for was the color profiles of each film, other traits related with processing, lenses and others are unlikely to be implemented, this includes: grain, vignetting, light leaks, cross-processing, etc.

Some before/after samples from his blog post:

You can read more on João’s website and you can see many more images on Flickr with the #t3mujinpack tag. The full list of film emulations included with his pack:

• AGFA APX 25, 100
• Fuji Astia 100F
• Fuji Neopan 1600, Acros 100
• Fuji Pro 160C, 400H, 800Z
• Fuji Provia 100F, 400F, 400X
• Fuji Sensia 100
• Fuji Superia 100, 200, 400, 800, 1600, HG 1600
• Fuji Velvia 50, 100
• Ilford Delta 100, 400, 3200
• Ilford FP4 125
• Ilford HP5 Plus 400
• Ilford XP2
• Kodak Ektachrome 100 GX, VS
• Kodak Ektar 100
• Kodak Elite Chrome 400
• Kodak Kodachrome 25, 64, 200
• Kodak Portra 160 NC, VC
• Kodak Portra 400 NC, UC, VC
• Kodak Portra 800
• Kodak T-Max 3200
• Kodak Tri-X 400

If you see João around the forums stop and say hi (and maybe a thank you). Even better, if you find these useful, consider buying him a beer (donation link is on his blog post)!

Related Reading

• color manipulation with the colour checker lut module (darktable)
• Pat David’s film emulation LUTs (G’MIC)
• Common Color Curves (Portra, Provia, Velvia) (RawTherapee)
• Pascal’s colormatch

The Royal Photographic Society Journal

Who let us in here?

The Journal of the Photographic Society is the journal for one of oldest photographic societies in the world: the Royal Photographic Society. First published in 1853, the RPS Journal is the oldest photographic periodical in the world (just edging out the British Journal of Photography by about a year).

So you can imagine my doubt when confronted with an email about using some material from pixls.us for their latest issue…

If the name sounds familiar to anyone it may be from a recent post by Joe McNally who is featured prominently in the September 2016 issue. He was also just inducted as a fellow into the society!

It turns out my initial doubts were completely unfounded, and they really wanted to run a page based off one of our tutorials. The editors liked the Open Source Portrait tutorial. In particular, the section on using Wavelet Decompose to touch up the skin tones:

How cool is that? I actually searched the archive and the only other mention I can find of GIMP (or any other F/OSS) is from a “Step By Step” article written by Peter Gawthrop (Vol. 149, February 2009). I think it’s pretty awesome that we can promote a little more exposure for Free Software alternatives. Especially in more mainstream publications and to a broader audience!

Arnold Newman Portraits

The beginnings of "Environmental Portraits"

Anyone that has spent any time around me would realize that I’m particularly fond of portraits. From the wonderful works of Martin Schoeller to the sublime Dan Winters, I am simply fascinated by a well executed portrait. So I thought it would be fun to take a look at some selections from the “father” of environmental portraits - Arnold Newman.

Newman wanted to become a painter before needing to drop out of college after only two years to take a job shooting portraits in a photo studio in Philadelphia. This experience apparently taught him what he did not want to do with photography…

Luckily it may have started defining what he did want to do with his photography. Namely, his approach to capturing his subjects alongside (or within) the context of the things that made them notable in some way. This would became known as “Environmental Portraiture”. He described it best in an interview for American Photo in 2000:

I didn’t just want to make a photograph with some things in the background. The surroundings had to add to the composition and the understanding of the person. No matter who the subject was, it had to be an interesting photograph. Just to simply do a portrait of a famous person doesn’t mean a thing. ¹

Though he has felt that the term might be unnecessarily restrictive (and possibly overshadows his other pursuits including abstractions and photojournalism), there’s no denying the impact of the results. Possibly his most famous portrait, of composer Igor Stravinsky, illustrates this wonderfully. The overall tones are almost monotone (flat - pun intended, and likely intentional on behalf of Newman) and are dominated by the stark duality of the white wall with the black piano.

Newman realized that the open lid of the piano “…is like the shape of a musical flat symbol—strong, linear, and beautiful, just like Stravinsky’s work.” ¹ The geometric construction of the image instantly captures the eye and the aggressive crop makes the final composition even more interesting. In this case the crop was a fundamental part of the original composition as shot, but it was not uncommon for him to find new life in images with different crops.

In a similar theme his portraits of both Salador Dalí and John F. Kennedy show a willingness to allow the crop to bring in different defining characteristics of his subjects. In the case of Dalí it allows an abstraction to hang there mimicking the pose of the artist himself. Kennedy is mostly the only organic form, striking a relaxed pose, while dwarfed by the imposing architecture and hard lines surrounding him.

He manages to bring the same deft handling of placing his subjects in the context of their work with other photographers as well. His portrait of Ansel Adams shows the photographer just outside his studio with the surrounding wilderness not only visible around the frame but reflected in the glass of the doors behind him (and the photographers glasses). Perhaps an indication of the nature of Adams work being to capture natural scenes through glass?

For anyone familiar with the pioneer of another form of photography, Newman’s portrait of (the usually camera shy) Henri Cartier-Bresson will instantly evoke a sense of the artists candid street images. In it, Bresson appears to take the place of one of his subjects caught briefly on the streets in a fleeting moment. The portrait has an almost spontaneous feeling to it, (again) mirroring the style of the work of its subject.

Eight years after his portrait of surrealist painter Dali, Newman shot another famous (abstraction) artist, Pablo Picasso. This particular portrait is much more intimate and more classically composed, framing the subject as a headshot with little of the surrounding environment as before. I can’t help but think that the placement of the hand being similar in both images is intentional; a nod to the unconventional views both artists brought to the world.

The eloquent Gregory Heisler had a wonderful discussion about Newman for Atlanta Celebrates Photography at the High Musuem in 2008:

Arnold Newman produced an amazing body of work that warrants some time and consideration for anyone interested in portraiture. These few examples simply do not do his collection of portraits justice. If you have a few moments to peruse some amazing images head over to his website and have a look (I’m particularly fond of his extremely design-oriented portrait of chinese-american architect I.M. Pei):

Of historical interest is a look at Newman’s contact sheet for the Stravinsky image showing various compositions and approaches to his subject with the piano. (I would have easily chosen the last image in the first row as my pick.) I have seen the second image in the second row cropped as indicated, which was also a very strong choice. I adore being able to investigate contact sheets from shoots like this - it helps me to humanize these amazing photographers while simultaneously allowing me an opportunity to learn a little about their thought process and how I might incorporate it into my own photography.

To close, a quote from his interview with American Photo magazine back in 2000 that will likely remain relevant to photographers for a long time:

But a lot of photographers think that if they buy a better camera they’ll be able to take better photographs. A better camera won’t do a thing for you if you don’t have anything in your head or in your heart. ¹

¹ Harris, Mark. “Arnold Newman: The Stories Behind Some of the Most Famous Portraits of the 20th Century.” American Photo, March/April 2000, pp. 36-38

From the Community Vol. 1

Welcome to the first installment of From the Community, a (hopefully) quarterly blog post to highlight a few of the things our community members have been doing!

Rapid Photo Downloader Process Model

@damonlynch has a great write up of Rapid Photo Download’s process model. Rapid Photo Downloader is built using Python, so if you’re looking for a good way to add threads to your Python program, this write up has some good information for you, check it out!

Community-built Software downloads page

Free Software development tends to move at a pretty good pace, so there is always something new to try out! Not all of the new things warrant a new release, but our community steps up and builds the software so that others can use and test! Instead of random links to dropboxes and such, we’ve created a Community-built Software page to help centralize and make it easy for our users to help find and download the freshest builds of software from our great community members. Keep in mind that support may be limited for these builds and they’re considered testing, so quality may vary, but if you covet the newest, shiniest things, this is the place for you!

Glitch art filters coming to G’MIC

G’MIC will be getting some cool glitch art filters in 1.7.6. @thething is interested in glitch art and requested some new filters in G’MIC, and @David_Tschumperle delivered very quickly!

You can flip blocks:

and warp your images:

An Alternative to Watermarking

Watermarking is ugly and takes focus away from your image. Why not try and add an attribution bar to your images? In this post, @patdavid lays out how to add a bar underneath your image with your name, the image title, and a little logo. @David_Tschumperle followed that effort up with an alternate implementation using G’MIC instead of imagemagic. Lastly, @vato rolled the imagemagick version into a bash script with the necessary parameters exposed as variables at the beginning of the script.

Here is an example image by @Morgan_Hardwood:

Help Author a Tutorial for Beginners

Finally, we’re still working on our beginner article to help new users navigate the myriad of free software photography software that is out there. If you have ideas, or better yet, want to author a bit of content with our community, please join and help out! The post is community wiki and has complete revision control, so don’t be afraid to jump in and contribute!

HD Photo Slideshow with Blender

Because who doesn't love a challenge?

While I was out at Texas Linux Fest this past weekend I got to watch a fun presentation from the one and only Brian Beck. He walked through an introduction to Blender, including an overview of creating his great The Lady in the Roses image that was a part of the 2015 Libre Calendar project.

Coincidentally, during my trip home community member @Fotonut asked about software to create an HD slideshow with images. The first answer that jumped into my mind was to consider using Blender (a very close second was OpenShot because I had just spent some time talking with Jon Thomas about it).

I figured this much Blender being talked about deserved at least a post to answer @Fotonut‘s question in greater detail. I know that many community members likely abuse Blender in various ways as well – so please let me know if I get something way off!

Enter Blender

The reason that Blender was the first thing that popped into many folks minds when the question was posed is likely because it has been a go-to swiss-army knife of image and video creation for a long, long time. For some it was the only viable video editing application for heavy use (not that there weren’t other projects out there as well). This is partly due to to the fact that it integrates so much capability into a single project.

The part that we’re interested in for the context of Fotonut’s original question is the Video Sequence Editor (VSE). This is a very powerful (though often neglected) part of Blender that lets you arrange audio and video (and image!) assets along a timeline for rendering and some simple effects. Which is actually perfect for creating a simple HD slideshow of images, as we’ll see.

The Plan

Blenders interface is likely to take some getting used to for newcomers (right-click!) but we’ll be focusing on a very small subset of the overall program—so hopefully nobody gets lost. The overall plan will be:

1. Setup the environment for video sequence editing
2. Include assets (images) and how to manipulate them on the timeline
3. Add effects such as cross-fades between images
4. Setup exporting options

There’s also an option of using a very helpful add-on for automatically resizing images to the correct size to maintain their aspect ratios. Luckily, Blender’s add-on system makes it trivially easy to set up.

Setup

On opening Blender for the first time we’re presented with the comforting view of the default cube in 3D space. Don’t get too cozy, though. We’re about to switch up to a different screen layout that’s already been created for us by default for Video Editing.

The developers were nice enough to include various default “Screen Layout” options for different tasks, and one of them happens to be for Video Editing. We can click on the screen layout option on the top menu bar and choose the one we want from the list (Video Editing):

Our screen will then change to the new layout where the top left pane is the F-curve window, the top right is the video preview, the large center section is the sequencer, and the very bottom is a timeline. Blender will let you arrange, combine, and collapse all the various panes into just about any layout that you might want, including changing what each of them are showing. For our example we will mostly leave it all as-is with the exception of the F-curve pane, which we won’t be using and don’t need.

What we can do now is to define what the resolution and framerate of our project should be. This is done in the Properties pane, which isn’t shown right now. So we will change the F-Curve pane into the Properties pane by clicking on the button shown in red above to change the panel type. We want to choose Properties from the options in the list:

Which will turn the old F-Curve pane into the Properties pane:

You’ll want to set the appropriate X and Y resolution for your intended output (don’t forget to set the scaling from the default 50% to 100% now as well) as well as your intended framerate. Common rates might be 23.976 (23.98), 25, 30, or even 60 frames per second. If your intended target is something like YouTube or an HD television you can probably safely use 30 or 60 (just remember that a higher frame rate means a longer render time!).

For our example I’m going to set the output resolution to 1920 × 1080 at 30fps.

One Extra Thing

Blender does need a little bit of help when it comes to using images on the sequence editor. It has a habit of scaling images to whatever the output resolution is set to (ignoring the original aspect ratios). This can be fixed by simply applying a transform to the images but normally requires us to manually compute and enter the correct scaling factors to get the images back to their original aspect ratios.

I did find a nice small add-on on this thread at blenderartists.org that binds some handy shortcuts onto the VSE for us. The author kgeogeo has the add-on hosted on Github, and you can download the Python file directly from here: VSE Transform Tool (you can Right-Click and save the link). Save the .py file somewhere easy to find.

To load the add-on manually we’re going to change the Properties panel to User Preferences:

Click on the Add-ons tab to open that window and at the bottom of the panel is an option to “Install from File…”. Click that and navigate to the VSE_Transform_Tool.py file that you downloaded previously.

Once loaded, you’ll still need to Activate the plugin by clicking on the box:

That’s it! You’re now all set up to begin adding images and creating a slideshow. You can set the User Preferences pane back to Properties if you want to.

Adding Images

Let’s have a look at adding images onto the sequencer.

You can add images by either choosing Add → Image from the VSE menu and navigating to your images location, choosing them:

Or by drag-and-dropping your images onto the sequencer timeline from Nautilus, Finder, Explorer, etc…

When you do, you’ll find that a strip now appears on the VSE window (purple in my case) that represents your image. You should also see a preview of your video in the top-right preview window (sorry for the subject).

At this point we can use the handy add-on we installed previously by Right-Clicking on the purple strip to make sure it’s activated and then hitting the “T” key on the keyboard. This will automatically add a transform to the image that scales it to the correct aspect ratio for you. A small green Transform strip will appear above your purple image strip now:

Your image should now also be scaled to fit at the correct aspect ratio.

Adjusting the Image

If you scroll your mouse wheel in the VSE window, you will zoom in and out of time editor based on time (the x-axis in the sequencer window). You’ll notice that the time compresses or expands as you scroll the mouse wheel.

The middle-mouse button will let you pan around the sequencer.

The right-mouse button will select things. You can try this now by extending how long your image is displayed in the video. Right-Click on the small arrow on the end of the purple strip to activate it. A small number will appear above it indicating which frame it is currently on (26 in my example):

With the right handle active you can now either press “G” on the keyboard and drag the mouse to re-position the end of the strip, or Right-Click and drag to do the same thing. The timeline in seconds is shown along the bottom of the window for reference. If we wanted to let the image be visible for 5 seconds total, we could drag the end to the 5+00 mark on the sequencer window.

Since I set the framerate to 30 frames per second, I can also drag the end to frame 150 (30fps * 5s = 150 frames).

When you drag the image strip, the transform strip will automatically adjust to fit (so you don’t have to worry about it).

If you had selected the center of the image strip instead of the handle on one end and tried to move it, you would find that you can move the entire strip around instead of one end. This is how you can re-position image strips, which you may want to do when you add a second image to your sequencer.

Add a new image to your sequencer now following the same steps as above.

When I do, it adds a new strip back at the beginning of the timeline (basically where the current time is set):

I want to move this new strip so that it overlaps my first image by about half a second (or 15 frames). Then I will pull the right handle to resize the display time to about 5 seconds also.

Click on the new strip (center, not the ends), and press the “G” key to move it. Drag it right until the left side overlaps the previous image strip by a little bit:

When you click on the strip right handle to modify it’s length, notice the window on the far right of the VSE. The Edit Strip window should also show the strip “Length” parameter in case you want to change it by manually inputting a value (like 150):

I forgot to use the add-on to automatically fix the aspect ratio. With the strip selected I can press “T” at any time to invoke the add-on and fix the aspect ratio.

Adding a Transition Effect

With the two image strips slightly overlapping, we now want to define a simple cross fade between the two images as a transition effect. This is actually something alreayd built into the Blender VSE for us, and is easy to add. We _do_ need to be careful to select the right things to get the transition working correctly, though.

Once you’ve added a transform effect to a strip, you’ll need to make sure that subsequent operations use the transform strip as opposed to the original image strip.

For instance, to add a cross fade transition between these two images, click the first image strip transform (green), then Shift-Click on the second image transform strip (green). Now they are both selected, so add a Gamma Cross by using the Add menu in the VSE (Add → Effect Strip… → Gamma Cross):

This will add a Gamma Cross effect as a new strip that is locked to the two images overlap. It will do a cross-fade between the two images for the duration of the overlap. You can Left-Click now and scrub over the cross-fade strip to see it rendered in the preview window if you’d like:

At any time you can also use the hotkey “Alt-A” to view a render preview. This may run slow if your machine is not super-fast, but it should run enough to give you a general sense of what you’ll get.

If you want to modify the transition effect by changing its length, you can just increase the overlap between the strips as desired (using the original image strip — if you try to drag the transform strip you’ll find it locked to the original image strip and won’t move).

Repeat Repeat

You can basically follow these same steps for as many images as you’d like to include.

Exporting

To generate your output you’ll still need to change a couple of things to get what you want…

Render Length

You may notice on the VSE that there are vertical lines outside of which things will appear slightly grayed out. This is a visual indicator of the total start/end of the output. This is controlled via the Start and End frame settings on the timeline (bottom pane):

You’ll need to set the End value to match your last output frame from your video sequence. You can find this value by selecting the last strip in your sequence and pressing the “G” key: the start/end frame numbers of that last strip will be visible (you’ll want the last frame value, of course).

In my example above, my anticipated last frame should be 284, but the last render frame is currently set to 250. I would need to update that End frame to match my video to get output as expected.

Render Format

Back on the Properties panel (assuming you set the top-left panel back to Properties earlier—if not do so now), if we scroll down a bit we should see a section dedicated to Output.

You can change the various output options here to do frame-by-frame dumps or to encode everything into a video container of some sort. You can set the output directory to be something different if you don’t want it rendered into /tmp here.

For my example I will encode the video with H.264:

By choosing this option, Blender will then expose a new section of the Properties panel for setting the Encoding options:

I will often use the H264 preset and will enable the Lossless Output checkbox option. If I don’t have the disk space to spare I can also set different options to shrink the resulting filesize down further. The Bitrate option will have the largest effect on final file size and image quality.

When everything is ready (or you just want to test it out), you can render your output by scrolling back to the top of the Properties window and pressing the Animation button, or by hitting Ctrl-F12.

The Results

After adding portraits of all of the GIMP team from LGM London and adding gamma cross fade transitions, here are my results:

In Summary

This may seem overly complicated, but in reality much of what I covered here is the setup to get started and the settings for output. Once you’ve done this successfully it becomes pretty quick to use. One thing you can do is set up the environment the way you like it and then save the .blend file to use as a template for further work like this in the future. The next time you need to generate a slideshow you’ll have everything all ready to go and will only need to start adding images to the editor.

While looking for information on some VSE shortcuts I did run across a really interesting looking set of functions that I want to try out: the Blender Velvets. I’m going to go off and give it a good look when I get a chance as there’s quite a few interesting additions available.

For Blender users: did I miss anything?

Texas Linux Fest 2016

Everything's Bigger in Texas!

While in London this past April I got a chance to hang out a bit with LWN.net editor and fellow countryman, Nathan Willis. (It sounds like the setup for a bad joke: “An Alabamian and Texan meet in a London pub…”). Which was awesome because even though we were both at LGM2014, we never got a chance to sit down and chat.

So it was super-exciting for me to hear from Nate about possibly doing a photowalk and Free Software photo workshop at the 2016 Texas Linux Fest, and as soon as I cleared it with my boss, I agreed!

So… mosey on down to Austin, Texas on July 8-9 for Texas Linux Fest and join Akkana Peck and myself for a photowalk first thing of the morning on Friday (July 8) to be immediately followed by workshops from both of us. I’ll be talking about Free Software photography workflows and projects and Akkana will be focusing on a GIMP workshop.

This is part of a larger “Open Graphics” track on the entire first day that also includes Ted Gould creating technical diagrams using Inkscape, Brian Beck doing a Blender tutorial, and Jonathon Thomas showing off OpenShot 2.0. You can find the full schedule on their website.

I hope to see some of you there!

Color Manipulation with the Colour Checker LUT Module

hanatos tinkering in darktable again...

I was lucky to get to spend some time in London with the darktable crew. Being the wonderful nerds they are, they were constantly working on something while we were there. One of the things that Johannes was working on was the colour checker module for darktable.

Having recently acquired a Fuji camera, he was working on matching color styles from the built-in rendering on the camera. Here he presents some of the results of what he was working on.

This was originally published on the darktable blog, and is being republished here with permission. —Pat

motivation

for raw photography there exist great presets for nice colour rendition:

• in-camera colour processing such as canon picture styles
• fuji film-emulation-like presets (provia velvia astia classic-chrome)
• pat david’s film emulation luts

unfortunately these are eat-it-or-die canned styles or icc lut profiles. you have to apply them and be happy or tweak them with other tools. but can we extract meaning from these presets? can we have understandable and tweakable styles like these?

in a first attempt, i used a non-linear optimiser to control the parameters of the modules in darktable’s processing pipeline and try to match the output of such styles. while this worked reasonably well for some of pat’s film luts, it failed completely on canon’s picture styles. it was very hard to reproduce generic colour-mapping styles in darktable without parametric blending.

that is, we require a generic colour to colour mapping function. this should be equally powerful as colour look up tables, but enable us to inspect it and change small aspects of it (for instance only the way blue tones are treated).

overview

in git master, there is a new module to implement generic colour mappings: the colour checker lut module (lut: look up table). the following will be a description how it works internally, how you can use it, and what this is good for.

in short, it is a colour lut that remains understandable and editable. that is, it is not a black-box look up table, but you get to see what it actually does and change the bits that you don’t like about it.

the main use cases are precise control over source colour to target colour mapping, as well as matching in-camera styles that process raws to jpg in a certain way to achieve a particular look. an example of this are the fuji film emulation modes. to this end, we will fit a colour checker lut to achieve their colour rendition, as well as a tone curve to achieve the tonal contrast.

to create the colour lut, it is currently necessary to take a picture of an it8 target (well, technically we support any similar target, but didn’t try them yet so i won’t really comment on it). this gives us a raw picture with colour values for a few colour patches, as well as a in-camera jpg reference (in the raw thumbnail..), and measured reference values (what we know it should look like).

to map all the other colours (that fell in between the patches on the chart) to meaningful output colours, too, we will need to interpolate this measured mapping.

theory

we want to express a smooth mapping from input colours \(\mathbf{s}\) to target colours \(\mathbf{t}\), defined by a couple of sample points (which will in our case be the 288 patches of an it8 chart).

the following is a quick summary of what we implemented and much better described in JP’s siggraph course [0].

radial basis functions

radial basis functions are a means of interpolating between sample points via

$$f(x) = \sum_i c_i\cdot\phi(| x - s_i|),$$

with some appropriate kernel \(\phi(r)\) (we’ll get to that later) and a set of coefficients \(c_i\) chosen to make the mapping \(f(x)\) behave like we want it at and in between the source colour positions \(s_i\). now to make sure the function actually passes through the target colours, i.e. \(f(s_i) = t_i\), we need to solve a linear system. because we want the function to take on a simple form for simple problems, we also add a polynomial part to it. this makes sure that black and white profiles turn out to be black and white and don’t oscillate around zero saturation colours wildly. the system is

$$ \left(\begin{array}{cc}A &P\\P^t & 0\end{array}\right) \cdot \left(\begin{array}{c}\mathbf{c}\\\mathbf{d}\end{array}\right) = \left(\begin{array}{c}\mathbf{t}\\0\end{array}\right)$$

where

$$ A=\left(\begin{array}{ccc} \phi(r_{00})& \phi(r_{10})& \cdots \\ \phi(r_{01})& \phi(r_{11})& \cdots \\ \phi(r_{02})& \phi(r_{12})& \cdots \\ \cdots & & \cdots \end{array}\right),$$

and \(r_{ij} = | s_i - t_j |\) is the distance (CIE 76 \(\Delta\)E, \(\sqrt{(L_s - L_t)^2 + (a_s - a_t)^2 + (b_s - b_t)^2}\) ) between source colour \(s_i\) and target colour \(t_j\), in our case

$$P=\left(\begin{array}{cccc} L_{s_0}& a_{s_0}& b_{s_0}& 1\\ L_{s_1}& a_{s_1}& b_{s_1}& 1\\ \cdots \end{array}\right)$$

is the polynomial part, and \(\mathbf{d}\) are the coefficients to the polynomial part. these are here so we can for instance easily reproduce \(t = s\) by setting \(\mathbf{d} = (1, 1, 1, 0)\) in the respective row. we will need to solve this system for the coefficients \(\mathbf{c}=(c_0,c_1,\cdots)^t\) and \(\mathbf{d}\).

many options will do the trick and solve the system here. we use singular value decomposition in our implementation. one advantage is that it is robust against singular matrices as input (accidentally map the same source colour to different target colours for instance).

thin plate splines

we didn’t yet define the radial basis function kernel. it turns out so-called thin plate splines have very good behaviour in terms of low oscillation/low curvature of the resulting function. the associated kernel is

$$\phi(r) = r^2 \log r.$$

note that there is a similar functionality in gimp as a gegl colour mapping operation (which i believe is using a shepard-interpolation-like scheme).

creating a sparse solution

we will feed this system with 288 patches of an it8 colour chart. that means, with the added four polynomial coefficients, we have a total of 292 source/target colour pairs to manage here. apart from performance issues when executing the interpolation, we didn’t want that to show up in the gui like this, so we were looking to reduce this number without introducing large error.

indeed this is possible, and literature provides a nice algorithm to do so, which is called orthogonal matching pursuit [1].

this algorithm will select the most important hand full of coefficients \(\in \mathbf{c},\mathbf{d}\), to keep the overall error low. In practice we run it up to a predefined number of patches (\(24=6\times 4\) or \(49=7\times 7\)), to make best use of gui real estate.

the colour checker lut module

gui elements

when you select the module in darkroom mode, it should look something like the image above (configurations with more than 24 patches are shown in a 7\(\times\)7 grid instead). by default, it will load the 24 patches of a colour checker classic and initialise the mapping to identity (no change to the image).

• the grid shows a list of coloured patches. the colours of the patches are the source points \(\mathbf{s}\).
• the target colour \(t_i\) of the selected patch \(i\) is shown as offset controlled by sliders in the ui under the grid of patches.
• an outline is drawn around patches that have been altered, i.e. the source and target colours differ.
• the selected patch is marked with a white square, and the number shows in the combo box below.

interaction

to interact with the colour mapping, you can change both source and target colours. the main use case is to change the target colours however, and start with an appropriate palette (see the presets menu, or download a style somewhere).

• you can change lightness (L), green-red (a), blue-yellow (b), or saturation (C) of the target colour via sliders.
• select a patch by left clicking on it, or using the combo box, or using the colour picker
• to change source colour, select a new colour from your image by using the colour picker, and shift-left-click on the patch you want to replace.
• to reset a patch, double-click it.
• right-click a patch to delete it.
• shift-left-click on empty space to add a new patch (with the currently picked colour as source colour).

example use cases

example 1: dodging and burning with the skin tones preset

to process the following image i took of pat in the overground, i started with the skin tones preset in the colour checker module (right click on nothing in the gui or click on the icon with the three horizontal lines in the header and select the preset).

then, i used the colour picker (little icon to the right of the patch# combo box) to select two skin tones: very bright highlights and dark shadow tones. the former i dragged the brightness down a bit, the latter i brightened up a bit via the lightness (L) slider. this is the result:

example 2: skin tones and eyes

in this image, i started with the fuji classic chrome-like style (see below for a download link), to achieve the subdued look in the skin tones. then, i picked the iris colour and saturated this tone via the saturation slider.

as a side note, the flash didn’t fire in this image (iso 800) so i needed to stop it up by 2.5ev and the rest is all natural lighting..

use darktable-chart to create a style

as a starting point, i matched a colour checker lut interpolation function to the in-camera processing of fuji cameras. these have the names of old film and generally do a good job at creating pleasant colours. this was done using the darktable-chart utility, by matching raw colours to the jpg output (both in Lab space in the darktable pipeline).

here is the link to the fuji styles, and how to use them. i should be doing pat’s film emulation presets with this, too, and maybe styles from other cameras (canon picture styles?). darktable-chart will output a dtstyle file, with the mapping split into tone curve and colour checker module. this allows us to tweak the contrast (tone curve) in isolation from the colours (lut module).

these styles were created with the X100T model, and reportedly they work so/so with different camera models. the idea is to create a Lab-space mapping which is well configured for all cameras. but apparently there may be sufficient differences between the output of different cameras after applying their colour matrices (after all these matrices are just an approximation of the real camera to XYZ mapping).

so if you’re really after maximum precision, you may have to create the styles yourself for your camera model. here’s how:

step-by-step tutorial to match the in-camera jpg engine

note that this is essentially similar to pascal’s colormatch script, but will result in an editable style for darktable instead of a fixed icc lut.

• need an it8 (sorry, could lift that, maybe, similar to what we do for basecurve fitting)

• shoot the chart with your camera:

  • shoot raw + jpg
  • avoid glare and shadow and extreme angles, potentially the rims of your image altogether
  • shoot a lot of exposures, try to match L=92 for G00 (or look that up in your it8 description)

• develop the images in darktable:

  • lens and vignetting correction needed on both or on neither of raw + jpg
  • (i calibrated for vignetting, see lensfun)
  • output colour space to Lab (set the secret option in darktablerc: allow_lab_output=true)
  • standard input matrix and camera white balance for the raw, srgb for jpg.
  • no gamut clipping, no basecurve, no anything else.
  • maybe do perspective correction and crop the chart
  • export as float pfm

• darktable-chart

  • load the pfm for the raw image and the jpg target in the second tab
  • drag the corners to make the mask match the patches in the image
  • maybe adjust the security margin using the slider in the top right, to avoid stray colours being blurred into the patch readout
  • you need to select the gray ramp in the combo box (not auto-detected)
  • export csv

edit the csv in a text editor and manually add two fixed fake patches HDR00 and HDR01:

name;fuji classic chrome-like
description;fuji classic chrome-like colorchecker
num_gray;24
patch;L_source;a_source;b_source;L_reference;a_reference;b_reference
A01;22.22;13.18;0.61;21.65;17.48;3.62
A02;23.00;24.16;4.18;26.92;32.39;11.96
...
HDR00;100;0;0;100;0;0
HDR01;200;0;0;200;0;0
...

this is to make sure we can process high-dynamic range images and not destroy the bright spots with the lut. this is needed since the it8 does not deliver any information out of the reflective gamut and for very bright input. to fix wide gamut input, it may be needed to enable gamut clipping in the input colour profile module when applying the resulting style to an image with highly saturated colours. darktable-chart does that automatically in the style it writes.

• fix up style description in csv if you want
• run darktable-chart --csv
• outputs a .dtstyle with everything properly switched off, and two modules on: colour checker + tonecurve in Lab

fitting error

when processing the list of colour pairs into a set of coefficients for the thin plate spline, the program will output the approximation error, indicated by average and maximum CIE 76 \(\Delta\)E for the input patches (the it8 in the examples here). of course we don’t know anything about colours which aren’t represented in the patch. the hope would be that the sampling is dense enough for all intents and purposes (but nothing is holding us back from using a target with even more patches).

for the fuji styles, these errors are typically in the range of mean \(\Delta E\approx 2\) and max \(\Delta E \approx 10\) for 24 patches and a bit less for 49. unfortunately the error does not decrease very fast in the number of patches (and will of course drop to zero when using all the patches of the input chart).

provia 24:rank 28/24 avg DE 2.42189 max DE 7.57084
provia 49:rank 53/49 avg DE 1.44376 max DE 5.39751

astia-24:rank 27/24 avg DE 2.12006 max DE 10.0213
astia-49:rank 52/49 avg DE 1.34278 max DE 7.05165

velvia-24:rank 27/24 avg DE 2.87005 max DE 16.7967
velvia-49:rank 53/49 avg DE 1.62934 max DE 6.84697

classic chrome-24:rank 28/24 avg DE 1.99688 max DE 8.76036
classic chrome-49:rank 53/49 avg DE 1.13703 max DE 6.3298

mono-24:rank 27/24 avg DE 0.547846 max DE 3.42563
mono-49:rank 52/49 avg DE 0.339011 max DE 2.08548

future work

it is possible to match the reference values of the it8 instead of a reference jpg output, to calibrate the camera more precisely than the colour matrix would.

• there is a button for this in the darktable-chart tool
• needs careful shooting, to match brightness of reference value closely.
• at this point it’s not clear to me how white balance should best be handled here.
• need reference reflectances of the it8 (wolf faust ships some for a few illuminants).

another next step we would like to take with this is to match real film footage (porta etc). both reference and film matching will require some global exposure calibration though.

references

• [0] Ken Anjyo and J. P. Lewis and Frédéric Pighin, “Scattered data interpolation for computer graphics” in Proceedings of SIGGRAPH 2014 Courses, Article No. 27, 2014. pdf
• [1] J. A. Tropp and A. C. Gilbert, “Signal Recovery From Random Measurements Via Orthogonal Matching Pursuit”, in IEEE Transactions on Information Theory, vol. 53, no. 12, pp. 4655-4666, Dec. 2007.

links

• pat david’s film emulation luts
• download fuji styles
• darktable’s user manual on styles
• it8 target
• pascal’s colormatch
• lensfun calibration
• perspective correction in darktable
• fit basecurves for darktable

Sharing is Caring

Letting it all hang out

It was always my intention to make the entire PIXLS.US website available under a permissive license. The content is already all licensed Creative Commons, By Attribution, Share-Alike (unless otherwise noted). I just hadn’t gotten around to actually posting the site source.

Until now(ish). I say “ish“ because I apparently released the code back in April and am just now getting around to talking about it.

Also, we finally have a category specifically for all those darktable weenies on discuss!

Don’t Laugh

I finally got around to pushing my code for this site up to Github on April 27 (I’m basing this off git logs because my memory is likely suspect). It took a while, but better late than never? I think part of the delay was a bit of minor embarrassment on my part for being so sloppy with the site code. In fact, I’m still embarrassed - so don’t laugh at me too hard (and if you do, at least don’t point while laughing too).

So really this post is just a reminder to anyone that was interested that this site is available on Github:

https://github.com/pixlsus/

In fact, we’ve got a couple of other repositories under the Github Organization PIXLS.US including this website, presentation assets, lighting diagram SVG’s, and more. If you’ve got a Github account or wanted to join in with hacking at things, by all means send me a note and we’ll get you added to the organization asap.

Note: you don’t need to do anything special if you just want to grab the site code. You can do this quickly and easily with:

git clone https://github.com/pixlsus/website.git

You actually don’t even need a Github account to clone the repo, but you will need one if you want to fork it on Github itself, or to send pull-requests. You can also feel free to simply email/post patches to us as well:

git format-patch testing --stdout > your_awesome_work.patch

Being on Github means that we also now have an issue tracker to report any bugs or enhancements you’d like to see for the site.

So no more excuses - if you’d like to lend a hand just dive right in! We’re all here to help! :)

Speaking of Helping

Speaking of which, I wanted to give a special shout-out to community member @paperdigits (Mica), who has been active in sharing presentation materials in the Presentations repo and has been actively hacking at the website. Mica’s recommendations and pull requests are helping to make the site code cleaner and better for everyone, and I really appreciate all the help (even if I _am_ scared of change).

Thank you, Mica! You rock!

Those Stinky darktable People

Yes, after member Claes asked the question on discuss about why we didn’t have a darktable category on the forums, I relented and created one. Normally I want to make sure that any category is going to have active people to maintain and monitor the topics there. I feel like having an empty forum can sometimes be detrimental to the perception of a project/community.

In this case, any topics in the darktable category will also show up in the more general Software category as well. This way the visibility and interactions are still there, but with the added benefit that we can now choose to see only darktable posts, ignore them, or let all those stinky users do what they want in there.

Besides, now we can say that we’ve sufficiently appeased Morgan Hardwood‘s organizational needs…

So, come on by and say hello in the brand new darktable category!

Sharing Galore

or, Why This Community is Awesome

Community member and RawTherapee hacker Morgan Hardwood brings us a great tutorial + assets from one of his strolls near the Söderåsen National Park (Sweden!). Ofnuts is apparently trying to get me to burn the forum down by sharing his raw file of a questionable subject. After bugging David Tschumperlé he managed to find a neat solution to generating a median (pixel) blend of a large number of images without making your computer throw itself out a window.

So much neat content being shared for everyone to play with and learn from! Come see what everyone is doing!

Old Oak - A Tutorial

Sometimes you’re just hanging out minding your own business and talking photography with friends and other Free Software nuts when someone comes running by and drops a great tutorial in your lap. Just as Morgan Hardwood did on the forums a few days ago!

He introduces the image and post:

There is an old oak by the southern entrance to the Söderåsen National Park. Rumor has it that this is the oak under which Gandalf sat as he smoked his pipe and penned the famous saga about J.R.R. Tolkien. I don’t know about that, but the valley rabbits sure love it.

The image itself is a treat. I personally love images where the lighting does interesting things and there are some gorgeous things going on in this image. The diffused light flooding in under the canopy on the right with the edge highlights from the light filtering down make this a pleasure to look at.

Of course, Morgan doesn’t stop there. You should absolutely go read his entire post. He not only walks through his entire thought process and workflow starting at his rationale for lens selection (50mm f/2.8) all the way through his corrections and post-processing choices. To top it all off, he has graciously shared his assets for anyone to follow along! He provides the raw file, the flat-field, a shot of his color target + DCP, and finally his RawTherapee .PP3 file with all of his settings! Whew!

If you’re interested I urge you to go check out (and participate!) in his topic on the forums: Old Oak - A Tutorial.

I Will Burn This Place to the Ground

Speaking of sharing material, Ofnuts has decided that he apparently wants me to burn the forums to the ground, put the ashes in a spaceship, fly the spaceship into the sun, and to detonate the entire solar system into a singularity. Why do I say this?

Because he started a topic appropriately entitled: “NSFPAOA (Not Suitable for Pat and Other Arachnophobes)”, in which he shares his raw .CR2 file for everyone to try their hand at processing that cute little spider above. There have already been quite a few awesome interpretations from folks in the community like:

Of course, I had a chance to try processing it as well. Here’s what I ended up with:

Ahhhh, just writing this post is a giant bag of NOPE^*. If you’d like to join in on the fun(?) and share your processing as well - go check out the topic!

Now let’s move on to something more cute and fuzzy, like an ALOT…

^* I kid, I’m not really an arachnophobe (within reason), but I can totally see why someone would be.

Median Blending ALOT of Images with G’MIC

I count myself lucky to have so many smart friends that I can lean on to figure out or help me do things (more on that in the next post). One of those friends is G’MIC creator and community member David Tschumperlé.

A few years back he helped me with some artwork I was generating with imagemagick at the time. I was averaging images together to see what an amalgamation would look like. For instance, here is what all of the Sports Illustrated swimsuit edition (NSFW) covers (through 2000) look like, all at once:

A natural progression of this idea was to consider doing a median blend vs. mean. The problem is that a mean average is very easy and fast to calculate as you advance through the image stack, but the median is not. This is relevant because I began to look at these for videos (in particular music videos), where the image stack was 5,000+ images for a video easily (that is ALOT of frames!).

It’s relatively easy to generate a running average for a series of numbers, but generating the median value requires that the entire stack of numbers be loaded and sorted. This makes it prohibitive to do on a huge number of images, particularly at HD resolutions.

So it’s awesome that, yet again, David has found a solution to the problem! He explains it in greater detail on his topic:

A guide about computing the temporal average/median of video frames with G’MIC

He basically chops up the image frame into regions, then computes the pixel-median value for those regions. Here’s an example of his result:

Now I can start utilizing median blends more often in my experiments, and I’m quite sure folks will find other interesting uses for this type of blending!

New Rapid Photo Downloader

Damon Lynch brings us a new release!

Community member Damon Lynch happens to make an awesome program called Rapid Photo Downloader in his “spare” time. In fact you may have heard mention of it as part of Riley Brandt’s “The Open Source Photography Course”^*. It is a program that specializes in downloading photo and video from media in as efficient a manner as possible while extending the process with extra functionality.

^* Riley donates a portion of the proceeds from his course to various projects, and Rapid Photo Downloader is one of them!

Work Smart, not Dumb

The main features of Rapid Photo Downloader are listed on the website:

1. Generates meaningful, user configurable file and folder names
2. Downloads photos and videos from multiple devices simultaneously
3. Backs up photos and videos as they are downloaded
4. Is carefully optimized to download and back up at high speed
5. Easy to configure and use
6. Runs under Unity, Gnome, KDE and other Linux desktops
7. Available in thirty languages
8. Program configuration and use is fully documented

Damon announced his 0.9.0a1 release on the forums, and Riley Brandt even recorded a short overview of the new features:

(Shortly after announcing the 0.9.0a1 release, he followed it up with a 0.9.0a2 release with some bug fixes).

Some of the neat new features include being able to preview the download subfolder and storage space of devices before you download:

Also being able to download from multiple devices in parallel, including from all cameras supported by gphoto2:

There is much, much more in this release. Damon goes into much further detail on his post in the forum, copied here:

How about its Timeline, which groups photos and videos based on how much time elapsed between consecutive shots. Use it to identify photos and videos taken at different periods in a single day or over consecutive days.

You can adjust the time elapsed between consecutive shots that is used to build the Timeline to match your shooting sessions.

How about a modern look?

Download instructions: http://damonlynch.net/rapid/download.html

For those who’ve used the older version, I’m copying and pasting from the ChangeLog, which covers most but not all changes:

• New features compared to the previous release, version 0.4.11:

  • Every aspect of the user interface has been revised and modernized.

  • Files can be downloaded from all cameras supported by gPhoto2, including smartphones. Unfortunately the previous version could download from only some cameras.

  • Files that have already been downloaded are remembered. You can still select previously downloaded files to download again, but they are unchecked by default, and their thumbnails are dimmed so you can differentiate them from files that are yet to be downloaded.

  • The thumbnails for previously downloaded files can be hidden.

  • Unique to Rapid Photo Downloader is its Timeline, which groups photos and videos based on how much time elapsed between consecutive shots. Use it to identify photos and videos taken at different periods in a single day or over consecutive days. A slider adjusts the time elapsed between consecutive shots that is used to build the Timeline. Time periods can be selected to filter which thumbnails are displayed.

  • Thumbnails are bigger, and different file types are easier to distinguish.

  • Thumbnails can be sorted using a variety of criteria, including by device and file type.

  • Destination folders are previewed before a download starts, showing which subfolders photos and videos will be downloaded to. Newly created folders have their names italicized.

  • The storage space used by photos, videos, and other files on the devices being downloaded from is displayed for each device. The projected storage space on the computer to be used by photos and videos about to be downloaded is also displayed.

  • Downloading is disabled when the projected storage space required is more than the capacity of the download destination.

  • When downloading from more than one device, thumbnails for a particular device are briefly highlighted when the mouse is moved over the device.

  • The order in which thumbnails are generated prioritizes representative samples, based on time, which is useful for those who download very large numbers of files at a time.

  • Thumbnails are generated asynchronously and in parallel, using a load balancer to assign work to processes utilizing up to 4 CPU cores. Thumbnail generation is faster than the 0.4 series of program releases, especially when reading from fast memory cards or SSDs. (Unfortunately generating thumbnails for a smartphone’s photos is painfully slow. Unlike photos produced by cameras, smartphone photos do not contain embedded preview images, which means the entire photo must be downloaded and cached for its thumbnail to be generated. Although Rapid Photo Downloader does this for you, nothing can be done to speed it up).

  • Thumbnails generated when a device is scanned are cached, making thumbnail generation quicker on subsequent scans.

  • Libraw is used to render RAW images from which a preview cannot be extracted, which is the case with Android DNG files, for instance.

  • Freedesktop.org thumbnails for RAW and TIFF photos are generated once they have been downloaded, which means they will have thumbnails in programs like Gnome Files, Nemo, Caja, Thunar, PCManFM and Dolphin. If the path files are being downloaded to contains symbolic links, a thumbnail will be created for the path with and without the links. While generating these thumbnails does slow the download process a little, it’s a worthwhile tradeoff because Linux desktops typically do not generate thumbnails for RAW images, and thumbnails only for small TIFFs.

  • The program can now handle hundreds of thousands of files at a time.

  • Tooltips display information about the file including name, modification time, shot taken time, and file size.

  • Right click on thumbnails to open the file in a file browser or copy the path.

  • When downloading from a camera with dual memory cards, an emblem beneath the thumbnail indicates which memory cards the photo or video is on

  • Audio files that accompany photos on professional cameras like the Canon EOS-1D series of cameras are now also downloaded. XMP files associated with a photo or video on any device are also downloaded.

  • Comprehensive log files are generated that allow easier diagnosis of program problems in bug reports. Messages optionally logged to a terminal window are displayed in color.

  • When running under Ubuntu‘s Unity desktop, a progress bar and count of files available for download is displayed on the program’s launcher.

  • Status bar messages have been significantly revamped.

  • Determining a video’s correct creation date and time has been improved, using a combination of the tools MediaInfo and ExifTool. Getting the right date and time is trickier than it might appear. Depending on the video file and the camera that produced it, neither MediaInfo nor ExifTool always give the correct result. Moreover some cameras always use the UTC time zone when recording the creation date and time in the video’s metadata, whereas other cameras use the time zone the video was created in, while others ignore time zones altogether.

  • The time remaining until a download is complete (which is shown in the status bar) is more stable and more accurate. The algorithm is modelled on that used by Mozilla Firefox.

  • The installer has been totally rewritten to take advantage of Python‘s tool pip, which installs Python packages. Rapid Photo Downloader can now be easily installed and uninstalled. On Ubuntu, Debian and Fedora-like Linux distributions, the installation of all dependencies is automated. On other Linux distrubtions, dependency installation is partially automated.

  • When choosing a Job Code, whether to remember the choice or not can be specified.

• Removed feature:

  • Rotate Jpeg images - to apply lossless rotation, this feature requires the program jpegtran. Some users reported jpegtran corrupted their jpegs’ metadata – which is bad under any circumstances, but terrible when applied to the only copy of a file. To preserve file integrity under all circumstances, unfortunately the rotate jpeg option must therefore be removed.

• Under the hood, the code now uses:

  • PyQt 5.4 +

  • gPhoto2 to download from cameras

  • Python 3.4 +

  • ZeroMQ for interprocess communication

  • GExiv2 for photo metadata

  • Exiftool for video metadata

  • Gstreamer for video thumbnail generation

• Please note if you use a system monitor that displays network activity, don’t be alarmed if it shows increased local network activity while the program is running. The program uses ZeroMQ over TCP/IP for its interprocess messaging. Rapid Photo Downloader’s network traffic is strictly between its own processes, all running solely on your computer.

• Missing features, which will be implemented in future releases:

  • Components of the user interface that are used to configure file renaming, download subfolder generation, backups, and miscellaneous other program preferences. While they can be configured by manually editing the program’s configuration file, that’s far from easy and is error prone. Meanwhile, some options can be configured using the command line.

  • There are no full size photo and video previews.

  • There is no error log window.

  • Some main menu items do nothing.

  • Files can only be copied, not moved.

Of course, Damon doesn’t sit still. He quickly followed up the 0.9.0a1 announcement by announcing 0.9.0a2 which included a few bug fixes from the previous release:

• Added command line option to import preferences from from an old program version (0.4.11 or earlier).

• Implemented auto unmount using GIO (which is used on most Linux desktops) and UDisks2 (all those desktops that don’t use GIO, e.g. KDE).

• Fixed bug while logging processes being forcefully terminated.

• Fixed bug where stored sequence number was not being correctly used when renaming files.

• Fixed bug where download would crash on Python 3.4 systems due to use of Python 3.5 only math.inf

If you’ve been considering optimizing your workflow for photo import and initial sorting now is as good a time as any - particularly with all of the great new features that have been packed into this release! Head on over to the Rapid Photo Downloader website to have a look and see the instructions for getting a copy:

http://damonlynch.net/rapid/download.html

Remember, this is Alpha software still (though most of the functionality is all in place). If you do run into any problems, please drop in and let Damon know in the forums!

G'MIC 1.7.1

When the flowers are blooming, image filters abound!

A new version 1.7.1 “Spring 2016” of G’MIC (GREYC’s Magic for Image Computing), the open-source framework for image processing, has been released recently (26 April 2016). This is a great opportunity to summarize some of the latest advances and features over the last 5 months.

G’MIC: A brief overview

G’MIC is an open-source project started in August 2008. It has been developed in the IMAGE team of the GREYC laboratory from the CNRS (one of the major French public research institutes). This team is made up of researchers and teachers specializing in the algorithms and mathematics of image processing. G’MIC is released under the free software licence CeCILL (GPL-compatible) for various platforms (Linux, Mac and Windows). It provides a set of various user interfaces for the manipulation of generic image data, that is images or image sequences of multispectral data being _2D_ or _3D_, and with high-bit precision (up to 32bits floats per channel). Of course, it manages “classical” color images as well.

Note that the project just got a redesign of its mascot Gmicky, drawn by David Revoy, a French illustrator well-known to free graphics lovers for being responsible for the great libre webcomics Pepper&Carott.

G’MIC is probably best known for it’s GIMP plug-in, first released in 2009. Today, this popular GIMP extension proposes more than 460 customizable filters and effects to apply on your images.

But G’MIC is not a plug-in for GIMP only. It also offers a command-line interface, that can be used in addition with the CLI tools from ImageMagick or GraphicsMagick (this is undoubtly the most powerful and flexible interface of the framework). G’MIC also has a web service G’MIC Online to apply effects on your images directly from a web browser. Other G’MIC-based interfaces also exist (ZArt, a plug-in for Krita, filters for Photoflow…). All these interfaces are based on the generic C++ libraries CImg and libgmic which are portable, thread-safe and multi-threaded (through the use of OpenMP). Today, G’MIC has more than 900 functions to process images, all being fully configurable, for a library of only approximately 150 kloc of source code. It’s features cover a wide spectrum of the image processing field, with algorithms for geometric and color manipulations, image filtering (denoising/sharpening with spectral, variational or patch-based approaches…), motion estimation and registration, drawing of graphic primitives (up to 3d vector objects), edge detection, object segmentation, artistic rendering, etc. This is a versatile tool, useful to visualize and explore complex image data, as well as elaborate custom image processing pipelines (see these slides to get more information about the motivations and goals of the G’MIC project).

A selection of some new filters and effects

Here we look at the descriptions of some of the most significant filters recently added. We illustrate their usage from the G’MIC plug-in for GIMP. All of these filters are of course available from other interfaces as well (in particular within the CLI tool gmic).

Painterly rendering of photographs

The filter Artistic / Brushify tries to transform an image into a painting. Here, the idea is to simulate the process of painting with brushes on a white canvas. One provides a template image and the algorithm first analyzes the image geometry (local contrasts and orientations of the contours), then attempt to reproduce the image with a single brush that will be locally rotated and scaled accordingly to the contour geometry. By simulating enough of brushstrokes, one gets a “painted” version of the template image, which is more or less close to the original one, depending on the brush shape, its size, the number of allowed orientations, etc. All these settings being customizable by the user as parameters of the algorithm: This filter allows thus to render a wide variety of painting effects.

The animation below illustrates the diversity of results one can get with this filter, applied on the same input picture of a lion. Various brush shapes and geometries have been supplied to the algorithm. Brushify is computationally expensive so its implementation is parallelized (each core gives several brushstrokes simultaneously).

Note that it’s particularly fun to invoke this filter from the command line interface (using the option -brushify available in gmic) to process a sequence of video frames (see this example of “ brushified “ video):

Reconstructing missing data from sparse samples

G’MIC gets a new algorithm to reconstruct missing data in images. This is a classical problem in image processing, often named “Image Inpainting“, and G’MIC already had a lot of useful filters to solve this problem. Here, the newly added interpolation method assumes only a sparse set of image data is known, for instance a few scattered pixels over the image (instead of continuous chuncks of image data). The analysis and the reconstruction of the global image geometry is then particularly tough.

The new option -solidify in G’MIC allows the reconstruction of dense image data from such a sparse sampling, based on a multi-scale diffusion PDE’s-based technique. The figure below illustrates the ability of the algorithm with an example of image reconstruction. We start from an input image of a waterdrop, and we keep only 2.7% of the image data (a very little amount of data!). The algorithm is able to reconstruct a whole image that looks like the input, even if all the small details have not been fully reconstructed (of course!). The more samples we have, the finer details we can recover.

As this reconstruction technique is quite generic, several new G’MIC filters takes advantage of it:

• Filter Repair / Solidify applies the algorithm in a direct manner, by reconstructing transparent areas from the interpolation of opaque regions. The animation below shows how this filter can be used to create an artistic blur on the image borders.

From an artistic point of view, there are many possibilities offered by this filters. For instance, it becomes really easy to generate color gradients with complex shapes, as shown with the two examples below (also in this video that details the whole process).

• Filter Artistic / Smooth abstract uses same idea as the one with the waterdrop image: it purposely sub-samples the image in a sparse way, by choosing keypoints mainly on the image edges, then use the reconstruction algorithm to get the image back. With a low number of samples, the filter can only render a piecewise smooth image, i.e. a smooth abstraction of the input image.

• Filter Rendering / Gradient [random] is able to synthetize random colored backgrounds. Here again, the filter initializes a set of colors keypoints randomly chosen over the image, then interpolate them with the new reconstruction algorithm. We end up with a psychedelic background composed of randomly oriented color gradients.

• Simulation of analog films : the new reconstruction algorithm also allowed a major improvement for all the analog film emulation filters that have been present in G’MIC for years. The section Film emulation/ proposes a wide variety of filters for this purpose. Their goal is to apply color transformations to simulate the look of a picture shot by an analogue camera with a certain kind of film. Below, you can see for instance a few of the 300 colorimetric transformations that are available in G’MIC.

From an algorithmic point of view, such a color mapping is extremely simple to implement : for each of the 300+ presets, G’MIC actually has an HaldCLUT, that is a function defining for each possible color (R,G,B) (of the original image), a new color (R’,G’,B’) color to set instead. As this function is not necessarily analytic, a HaldCLUT is stored in a discrete manner as a lookup table that gives the result of the mapping for all possible colors of the RGB cube (that is 2^24 = 16777216 values if we work with a 8bits precision per color component). This HaldCLUT-based color mapping is illustrated below for all values of the RGB color cube.

This is a large amount of data: even by subsampling the RGB space (e.g. with 6 bits per component) and compressing the corresponding HaldCLUT file, you ends up with approximately 200 and 300 kB for each mapping file. Multiply this number by 300+ (the number of available mappings in G’MIC), and you get a total of 85MB of data, to store all these color transformations. Definitely not convenient to spread and package!

The idea was then to develop a new lossy compression technique focused on HaldCLUT files, that is volumetric discretised vector-valued functions which are piecewise smooth by nature. And that what has been done in G’MIC, thanks to the new sparse reconstruction algorithm. Indeed, the reconstruction technique also works with _3D_ image data (such as a HaldCLUT!), so one simply has to extract a sufficient number of significant keypoints in the RGB cube and interpolate them afterwards to allow the reconstruction of a whole HaldCLUT (taking care to have a reconstruction error small enough to be sure that the color mapping we get with the compressed HaldCLUT is indistinguishable from the non-compressed one).

Thus, G’MIC doesn’t need to store all the color data from a HaldCLUT, but only a sparse sampling of it (i.e. a sequence of { rgb_keypoint, new_rgb_color }). Depending on the geometric complexity of the HaldCLUTs to encode, more or less keypoints are necessary (roughly from _30_ to 2000). As a result, the storage of the 300+ HaldCLUTs in G’MIC requires now only 850 KiB of data (instead of 85 MiB), that is a compression gain of 99% ! That makes the whole HaldCLUT data storable in a single file that is easy to ship with the G’MIC package. Now, a user can then apply all the G’MIC color transformations while being offline (previously, each HaldCLUT had to be downloaded separately from the G’MIC server when requested).

It looks like this new reconstruction algorithm from sparse samples is really great, and no doubts it will be used in other filters in the future.

Make textures tileable

Filter Arrays & tiles / Make seamless [patch-based] tries to transform an input texture to make it tileable, so that it can be duplicated as tiles along the horizontal and vertical axes without visible seams on the borders of adjacent tiles. Note that this is something that can be extremely hard to achieve, if the input texture has few auto-similarity or glaring luminosity changes spatially. That is the case for instance with the “Salmon” texture shown below as four adjacent tiles (configuration 2x2) with a lighting that goes from dark (on the left) to bright (on the right). Here, the algorithm modifies the texture so that the tiling shows no seams, but where the aspect of the original texture is preserved as much as possible (only the texture borders are modified).

We can imagine some great uses of this filter, for instance in video games, where texture tiling is common to render large virtual worlds.

Image decomposition into several levels of details

A “new” filter Details / Split details [wavelets] has been added to decompose an image into several levels of details. It is based on the so-called “à trous” wavelet decomposition. For those who already know the popular Wavelet Decompose plug-in for GIMP, there won’t be so much novelty here, as it is mainly the same kind of decomposition technique that has been implemented. Having it directly in G’MIC is still a great news: it offers now a preview of the different scales that will be computed, and the implementation is parallelized to take advantage of multiple cores.

The filter outputs several layers, so that each layer contains the details of the image at a given scale. All those layers blended together gives the original image back.

Thus, one can work on those output layers separately and modify the image details only for a given scale. There are a lot of applications for this kind of image decomposition, one of the most spectacular being the ability to retouch the skin in portraits : the flaws of the skin are indeed often present in layers with middle-sized scales, while the natural skin texture (the pores) are present in the fine details. By selectively removing the flaws while keeping the pores, the skin aspect stays natural after the retouch (see this wonderful link for a detailed tutorial about skin retouching techniques, with GIMP).

Image denoising based on “Patch-PCA”

G’MIC is also well known to offer a wide range of algorithms for image denoising and smoothing (currently more than a dozen). And he got one more ! Filter Repair / Smooth [patch-pca] proposed a new image denoising algorithm that is both efficient and computationally intensive (despite its multi-threaded implementation, you probably should avoid it on a machine with less than 8 cores…). In return, it sometimes does magic to suppress noise while preserving small details.

The “Droste” effect

The Droste effect (also known as “mise en abyme“ in art) is the effect of a picture appearing within itself recursively. To achieve this, a new filter Deformations / Continuous droste has been added into G’MIC. It’s actually a complete rewrite of the popular Mathmap’s Droste filter that has existed for years. Mathmap was a very popular plug-in for GIMP, but it seems to be not maintained anymore. The Droste effect was one of its most iconic and complex filter. Martin “Souphead”, one former user of Mathmap then took the bull by the horns and converted the complex code of this filter specifically into a G’MIC script, resulting in a parallelized implementation of the filter.

This filter allows all artistic delusions. For instance, it becomes trivial to create the result below in a few steps: create a selection around the clock, move it on a transparent background, run the Droste filter, et voilà!.

Equirectangular to nadir-zenith transformation

The filter Deformations / Equirectangular to nadir-zenith is another filter converted from Mathmap to G’MIC. It is specifically used for the processing of panoramas: it reconstructs both the Zenith and the Nadir regions of a panorama so that they can be easily modified (for instance to reconstruct missing parts), before being reprojected back into the input panorama.

Morgan Hardwood has wrote a quite detailled tutorial, here on pixls.us, about the reconstruction of missing parts in the Zenith/Nadir of an equirectangular panorama. Check it out!

Other various improvements

Finally, here are other highlights about the G’MIC project:

• Filter Rendering / Kitaoka Spin Illusion is another Mathmap filter converted to G’MIC by Martin “Souphead”. It generates a certain kind of optical illusions as shown below (close your eyes if you are epileptic!)

• Filter Colors / Color blindness transforms the colors of an image to simulate different types of color blindness. This can be very helpful to check the accessibility of a web site or a graphical document for colorblind people. The color transformations used here are the same as defined on Coblis, a website that proposes to apply this kind of simulation online. The G’MIC filter gives strictly identical results, but it ease the batch processing of several images at once.

• Since a few years now, G’MIC has its own parser of mathematical expression, a really convenient module to perform complex calculations when applying image filters This core feature gets new functionalities: the ability to manage variables that can be complex, vector or matrix-valued, but also the creation of user-defined mathematical functions. For instance, the classical rendering of the Mandelbrot fractal set (done by estimating the divergence of a sequence of complex numbers) can be implemented like this, directly on the command line:

  $ gmic 512,512,1,1,"c = 2.4*[x/w,y/h] - [1.8,1.2]; z = [0,0]; for (iter = 0, cabs(z)<=2 && ++iter<256, z = z**z + c); 6*iter" -map 7,2
  

This clearly enlarge the math evaluator ability, as you are not limited to scalar variables anymore. You can now create complex filters which are able to solve linear systems or compute eigenvalues/eigenvectors, and this, for each pixel of an input image. It’s a bit like having a micro-(micro!)-Octave inside G’MIC. Note that the Brushify filter described earlier uses these new features extensively. It’s also interesting to know that the G’MIC math expression evaluator has its own JIT compiler to achieve a fast evaluation of expressions when applied on thousands of image values simultaneously.

• Another great contribution has been proposed by Tobias Fleischer, with the creation of a new _C_ API to invoke the functions of the libgmic library (which is the library containing all the G’MIC features, initially available through a C++ API only). As the _C_ ABI is standardized (unlike C++), this basically means G’MIC can be interfaced more easily with languages other than C++. In the future, we can imagine the development of G’MIC APIs for languages such as Python for instance. Tobias is currently using this new _C_ API to develop G’MIC-based plug-ins compatible with the OpenFX standard. Those plug-ins should be usable indifferently in video editing software such as After effects, Sony Vegas Pro or Natron. This is still an on-going work though.

• Another contributor Robin “Starfall Robles” started to develop a Python script to provide some of the G’MIC filters directly in the Blender video sequence editor. This work is still in a early stage, but you can already apply different G’MIC effects on image sequences (see this video for a demonstration).

• You can find out G’MIC filters also in the opensource nonlinear video editor Flowblade, thanks to the hard work of Janne Liljeblad (Flowblade project leader). Here again, the goal is to allow the application of G’MIC effects and filters directly on image sequences, mainly for artistic purposes (as shown in this video or this one).

What’s next ?

As you see, the G’MIC project is doing well, with an active development and cool new features added months after months. You can find and use interfaces to G’MIC in more and more opensource software, as GIMP, Krita, Blender, Photoflow, Flowblade, Veejay, EKD and Natron in a near future (at least we hope so!).

At the same time, we can see more and more external resources available for G’MIC : tutorials, blog articles (here, here, here,…), or demonstration videos (here, here, here, here,…). This shows the project becoming more useful to users of opensource software for graphics and photography.

The development of version 1.7.2 already hit the ground running, so stay tuned and visit the official G’MIC forum on pixls.us to get more info about the project developement and get answers to your questions. Meanwhile, feel the power of free software for image processing!

Links:

• G’MIC home page
• G’MIC plug-in for GIMP
• Introduction to the CLI interface of G’MIC
• Technical reference documentation
• G’MIC 1.7.1 release article on linuxfr.org

Post Libre Graphics Meeting

What a trip!

What a blast!

This trip report is long overdue, but I wanted to process some of my images to share with everyone before I posted.

It had been a couple of years since I had an opportunity to travel and meet with the GIMP team again (Leipzig was awesome) so I was really looking forward to this trip. I missed the opportunity to head up to the great white North for last years meeting in Toronto.

London Calling

I was going to attend the pre-LGM photowalk again this year so this time I decided to pack some bigger off-camera lighting modifiers for everyone to play with. Here’s a neat travelling photographer pro-tip: most airlines will let you carry on an umbrella as a “freebie” item. They just don’t specify that it has to be an umbrella to keep the rain off you. So I carried on my big Photek Softlighter II (luckily my light stands fit in my checked luggage). Just be sure not to leave it behind somewhere (which I was paranoid about for most of my trip). Luckily I was only changing planes in Atlanta.

A couple of (bad) movies and hours later I was in Heathrow. I figured it wouldn’t be much trouble getting through border control.

I may have been a little optimistic about that.

The Border Force agent was quite nice and super inquisitive. So much so that I actually began to worry at some point (I think I must have spent almost 20 minutes talking to her) that she might not let me in!

She kept asking what I was coming to London for and I kept trying to explain to her what a “Libre Graphics Meeting“ was. This was almost a tragic comedy. The idea of Free Software did not seem to compute to her and I was sorry I had even made the passing mention. Her attention then turned to my umbrella and photography. What was I there to photograph? Who? Why? (Come to think of it, I should start asking myself those same questions more often… It was an existential visit to the border control.)

In the end I think she got bored with my answers and figured that I was far too awkward to be a threat to anything. Which pretty much sums up my entire college dating life.

Photowalk

In what I hope will become a tradition we had our photowalk the day before LGM officially kicked off and we could not have asked for a better day of weather! It was partly cloudy and just gorgeous (pretty much the complete opposite to what I was expecting for London weather).

Furtherfield Commons

I want to thank Ruth Catlow (http://ruthcatlow.net/) for allowing us to use the awesome space at Furtherfield Commons in Finsbury Park as a base for our photowalk! They were amazingly accommodating and we had a wonderful time chatting in general about art and what they were up to at the gallery and space.

They have some really neat things going on at the gallery and space so be sure to check them out if you can!

Going for a Walk with Friends

This is one of my favorite things about being able to attend LGM. I get to take a stroll and talk about photography with friends that I only usually get to interact with through an IRC window. I also feel like I can finally contribute something back to these awesome people that provide software I use every day.

We meandered through the park and chatted a bit about various things. Simon had brought along his external flash and wanted to play with off-camera lighting. So we convinced Liam to stand in front of a tree for us and Simon ended up taking one of my favorite images from the entire trip. This was Liam standing in front of the tree under the shade with me holding the flash slightly above him and to the camera right.

We even managed to run into Barrie Minney while on our way back to the Commons building. Aryeom and I started talking a little bit while walking when we crossed paths with some locals hanging out in the park. One man in particular was quite outgoing and let Aryeom take his photo, leading to another fun image!

Upon returning to the Commons building we experimented with some of the pretty window light coming into the building along with some black panels and a model (Mairi). This was quite fun as we were experimenting with various setups for the black panels and speedlights. Everyone had a chance to try some shots out and to direct Mairi (who was super patient and accommodating while we played).

Towards the end of our day I decided get my big Softlighter out and to try a few things in the lane outside the Commons building. Luckily Michael Schumacher grabbed an image of us while we were testing some shots with Mairi outside.

I loved the lane receding in the background and thought it might make for some fun images of Mairi. I had two YN-560 flashes in the Softlighter both firing around ¾ power. I had to balance the ambient sky with the softlighter so needed the extra power of a second flash (it also helps to keep the cycle times down).

The day was awesome and I really enjoyed being able to just hang out with everyone and take some neat photos. The evening at the pub was pretty great also (I got to hang out with Barrie and his friend and have a couple of pints - thanks again Barrie!).

LGM

It never fails to amaze me how every year the LGM organizers manage to put together such a great meeting for everyone. The venue was great and the people were just fantastic at the University of Westminster.

The opening “State of the Libre Graphics“ presentation was done by our (the GIMP teams) very own João Bueno who did a fantastic job! João will also be the local organizer for the 2017 LGM in Rio.

Thanks to contributions from community members Kees Guequierre, Jonas Wagner, and Philipp Haegi I had some great images to use for the PIXLS.US community slides for the “State of the Libre Graphics“. If anyone is curious, here is what I submitted:

These slides can be found on our Github PIXLS.US Presentations page (along with all of our other presentations that relate to PIXLS.US and promoting the community).

Speaking of presentations…

Presentation

I was given some time to talk about and present our community to everyone at the meeting. (See embedded slides below):

I started by looking at what my primary motivation was to begin the site and what the state of free software photography was like at that time (or not like). Mainly that the majority of resources online for photographers that were high quality (and focused on high-quality results) were usually aimed at proprietary software users. Worse still, in some cases these websites locked away their best tutorials and learning content behind paywalls and subscriptions. I finished by looking at what was done to build this site and forum as a community for everyone to learn and share with each other freely.

I think the presentation went well and people seemed to be interested in what we were doing! Nate Willis even published an article about the presentation at LWN.net, “Refactoring the open-source photography community”:

Exhibition

A nice change this year was the inclusion of an exhibition space to display works by LGM members and artists. We even got an opportunity to hang a couple of prints (for some reason they really wanted my quad-print of pippin). I was particularly happy that we were able to print and display the Green Tiger Beetle by community member Kees Guequierre:

Portraits

In Leipzig I thought it would be nice to offer portraits/headshots of folks that attended the meeting. I think it’s a great opportunity to get a (hopefully) nice photograph that people can use in social media, avatars, websites, etc. Here’s a sample of portraits from LGM2014 of the GIMP team that sat for me:

In 2014 I was lucky that houz had brought along an umbrella and stand to use, so this time I figured it was only fair that I bring along some gear myself. I had the Softlighter setup on the last couple of days for anyone that was interested in sitting for us. I say us because Marek Kubica (@Leonidas) from the community was right there to shoot with me along with the very famous @Ofnuts (well - famous to me - I’ve lost count of the neat things I’ve picked up from his advice)! Marek took quite a few portraits and managed the subjects very well - he was conversational, engaged, and managed to get some great personality from them.

A couple of samples from the images that I got are here as well, and they are the local organizer Lara with students from the University! I simply can’t thank them enough for the efforts and generosity in making us feel so welcome.

I’m still working through the portraits I took, but I’ll have them uploaded to my Flickr soon to share with everyone!

GIMPers

One of the best parts of attendance is getting to spend some time with the rest of the GIMP crew. Here’s an action shot during the GIMP meeting over lunch with a neat, glitchy schumaml:

It was great to see everyone at the flat on our last evening there as well…

Wrap up

Overall this was another incredible meeting bringing together great folks who are building and supporting Free Software and Libre Graphics. Just my kind of crowd!

I even got a chance to speak a bit with the wonderful Susan Spencer of the Valentina project and we roughed out some thoughts about getting together at some point. It turns out she lives just up the same state as me (Alabama)! This is simply too great to not take advantage of - Free Software Fashion + Photography?! That will have to be a fun story (and photos) for another day…

Keep watching the blog for some more images from the trip - up next are the portraits of everyone and some more shots of the venue and exhibition!

Pre-LGM Photowalk

Time to take some photos!

It’s that time of year again! The weather is turning mild, the days are smelling fresh, and a bunch of photography nerds are all going to get together in a new country to roam around and (possibly) annoy locals by taking a ton of photographs! It’s the Pre-Libre Graphics Meeting photowalk of 2016!

Come join us the day before LGM kicks off to have a stroll through a lovely park and get a chance to shoot some photos between making new friends and having a pint.

Thanks to the wonderful work by the local LGM organizing team, we are able to invite everyone out to the photowalk on Thursday, April 14^th the day before LGM kicks off.

They were able to get us in touch with the kind folks at Furtherfield Gallery & Commons in Finsbury Park. They’ve graciously offered us the use of their facilities at the Furtherfield Commons as a base to start from. So we will meet at the Commons building at 10:00 on Thursday morning.

Pre-LGM Photowalk
10:00 (AM), Thursday, April 14^th
Furtherfield Commons
Finsbury Gate - Finsbury Park
Finsbury Park, London, N4 2NQ

An overview of the photowalk venue relative to the LGM venue at the University of Westminster, Harrow:

If you would like to join us but may not make it to the Commons by 10:00, email me and let me know. I’ll try my best to make arrangements to meet up so you can join us a little later. I can’t imagine we’d be very far away (likely somewhere relatively near by in the park).

We’ll plan on meandering through the park with frequent stops to shoot images that strike our fancy. I will personally be bringing along my off-camera lighting equipment and a model (Mairi) to pose for us during the day. In case anyone wanted to play/learn a little about that type of photography.

There is no set time for finishing up. I figured we would play it by ear through lunch and to possibly all finish up at a nice pub together. (Taking advantage of the golden hour light at the end of the day hopefully).

In the spirit of saying “Thank you!” and sharing, I have also offered the Furtherfield folks our services for headshots and architectural/environmental shots of the Commons and Gallery spaces. For sure I will be taking these images for them but if anyone else wanted to pitch in and try, help, or assist the effort would be very welcome!

Speaking of which, if you plan on attending and would like to explore some particular aspect of photography please feel free to let me know. I’ll do my best to match folks up based on interest. I sincerely hope this will be a fun opportunity to learn some neat new things, make some new friends, and to maybe grab some great images at the same time!

If there are any questions, please don’t hesitate to reach out to me!
`patdavid@gmail.com`
patdavid on irc://irc.gimp.org/#gimp

Happy Birthday DISCUSS.PIXLS.US

Where did the time go?!

For some reason I was checking my account on the forums earlier today and noticed that it was created in April, 2015. On further inspection it looks like my, and @darix, accounts were created on April 2^nd 2015.

(Not to be confused with the main site because apparently it took me about 8 months to get a forum stood up…)

Which means that the forums have been around for just over a year now?!

So, Happy Birthday discuss!

We’re just over a year old and just under 500 users on the forum!

For fun, I looked for the oldest (public) post we had and it looks like it’s the “Welcome to PIXLS.US Discussion“ thread. In case anyone wanted to revisit a classic…

THANK YOU so much to everyone who has made this an awesome place to be and nerd out about photography and software and more! Since we started we migrated the official G’MIC forums here as well as our friends at RawTherapee! We’ve been introduced to some awesome projects like PhotoFlow as well as Filmulator. And everyone has just been amazing, supportive, and fun to be around.

As I posted in the original Welcome thread…

Lighting Diagrams

Help Us Build Some Assets!

Community member Eric Mesa asked on the forums the other day if there might be some Free resources for photographers that want to build a lighting diagram of their work. These are the diagrams that show how a shot might be set up with the locations of lights, what types of modifiers might be used, and where the camera/photographer might be positioned with respect to the subject. These diagrams usually also include lighting power details and notes to help the production.

It turns out there wasn’t really anything openly available and permissively licensed. So we need to fix that…

These diagrams are particularly handy for planning a shoot conceptually or explaining what the lighting setup was to someone after the fact. For instance, here’s a look at the lighting setup for Sarah (Glance):

There are a few different commercial or restrictive-licensed options for photographers to create a lighting diagram, but nothing truly Free.

So thanks to the prodding by Eric, I thought it was something we should work on as a community!

I already had a couple of simple, basic shapes created in Inkscape for another tutorial so I figured I could at least get those files published for everyone to use.

I don’t have much to start with but that shouldn’t be a problem! I already had a backdrop, person, camera, octabox (+grid), and a softbox (+grid):

PIXLS.US Github Organization

I already have a GitHub organization setup just for PIXLS.US, you can find the lighting-diagram assets there:

https://github.com/pixlsus/pixls-lighting-diagram

Feel free to join the organization!

Even better: join the organization and fork the repo to add your own additions and to help us flesh out the available diagram assets for all to use! From the README.md on that repo, I compiled a list of things I thought might be helpful to create:

• Cameras
  • DSLR
  • Mirrorless
  • MF
• Strobes
  • Speedlight
  • Monoblock
• Lighting Modifiers
  • Softbox (+ grid?)
  • Umbrella (+ grid?)
  • Octabox (+ grid?)
  • Brolly
• Reflectors
• Flags
• Barn Doors / Gobo
• Light stands? (C-Stands?)
• Environmental
  • Chairs
  • Stools
  • Boxes
  • Backgrounds (+ stands)
• Models

If you don’t want to create something from scratch, perhaps grabbing the files and tweaking the existing assets to make them better in some way?

Hopefully we can fill out the list fairly quickly (as it’s a fairly limited subset of required shapes). Even better would be if someone picked up the momentum to possibly create a nice lighting diagram application of some sort!

The files that are there now are all licensed Creative Commons By-Attribution, Share-Alike 4.0.

PlayRaw (Again)

The Resurrectioning

On the old RawTherapee forums they used to have a contest sharing a single raw file amongst the members to see how everyone would approach processing from the same starting point. They called it PlayRaw. This seemed to really bring out some great work from the community so I thought it might be fun to start doing something similar again here.

I took a (relatively) recent image of Mairi and decided to see how it would be received (I’d say fairly well given the responses). This was my result from the raw file that I called Mairi Troisième:

I made the raw file available under a Creative Commons, By-Attribution, Non-Commercial, Share-Alike license so that anyone could freely download and process the file as they wanted to.

The only things I asked for was to see the results and possibly the processing steps through either an XMP or PP3 sidecar file (darktable and RawTherapee respectively).

Here’s a montage of the results from everyone:

I loved being able to see what everyone’s approaches looked like. It’s neat to get a feel for all the different visions out there among the users and there were some truly beautiful results!

If you haven’t given it a try yourself yet, head on over to the [PlayRaw] Mairi Troisieme thread to get the raw file and try it out yourself! Just don’t forget to show us your results in the topic.

I’ll be soliciting options for a new image to kick off another round of processing again soon.

Speaking of Mairi

Don’t forget that we still have a Pledgie Campaign going on to help us offset the costs of getting everyone together at the 2016 Libre Graphics Meeting in London this April!

Donations go to help cover to costs of various projects to come together and meet, photograph, discuss, and hack at things. Please consider donating as every little bit helps us immensely! If you can’t donate then please consider helping us to raise awareness of what we’re trying to do! Either link the Pledgie campaign to others or let them know we’re here to help and share!

Even better is if you’re in the vicinity of London this April 15–18! Come out and join us as well as many other awesome Free Software projects all focused on the graphics community! We (PIXLS) will be conducting photowalks and meet-ups the Thursday before LGM kicks off as well!

Oh, and I finally did convince Mairi to join us through the weekend to model for us as needed. She’s super awesome and worth raising a glass to/with! Even more reason to come out and join us!

Shimming an Adapter to be Parallel

Achieving perfect infinity focus

Some of you may know I exclusively use Contax manual focus lenses on my Canon cameras. I have had one reliable adapter from the start, that just happened to be perfect in every way: perfectly parallel, and lets my lenses focus exactly to infinity, and none of my lenses hit the mirror on my 5D.

However, swapping adapters between cameras gets mighty tedious, so recently I have been trying a variety of different adapters for my cameras, several quality tiers ranging from the cheapest ($15) up to the most expensive ($70).

However, I wasn’t satisfied with any of them. In order to assure that the adapted lenses can focus to infinity even with manufacturing tolerances, they’re made thinner than necessary. This means that they focus past infinity, and with some lenses the mirror of my 5D would hit the back of the lens, needing me to wiggle it to free the mirror after taking a photo.

I measured my fancier Fotodiox Pro adapter, and found that not only was it too thin, but it was unevenly thick! The top was 8 thousandths of an inch thin, the bottom right was 2 thousandth of an inch thin, and the bottom left was exactly the right thickness.

I decided I could do something about it.

I bought some shim stock from McMaster Carr, plastic and 2 thousandths of an inch thick, figuring I might be able to fold it to build up thickness if necessary. (Spoiler: it does fold.) It comes as a giant sheet five by twenty inches, but you’ll only need the tiniest amount of it.

Then I went about removing the screws that hold the two sides together.

The screws are incredibly small.

Here you can see that there are only three points on the ring that actually control the thickness; I point to one with the scissors. I had to be careful when measuring the thickness to only measure it between the screws, and that was challenging because the EF mount diameter is larger than the C/Y mount diameter, and there was only the slightest overlap between the outside of the C/Y registration surface and the inside of the EF mount.

Next I just cut a narrow strip out of this piece of shim stock using scissors, and put slits in it so it could fold more easily.

The right hand shim is folded in the shape of a W, and the left hand shim is only one layer.

The thicker shim went on the top, and the thinner shim went on the bottom-right.

Put the ring back on, and then…

Reinstall the screws.

Test your lenses for infinity focus and, if applicable, mirror slap, and rejoice if they’re good!

If you don’t have a perfect adapter as a reference for the proper thickness, you can first adjust the adapter to be perfectly even thickness all the way around, and then you can add thickness uniformly until your lenses just barely focus to infinity. It might be time consuming, but it’s very rewarding being able to trust the infinity stop on your lenses.

This method isn’t only applicable to the two-part SLR->SLR Fotodiox adapters; it should also work for SLR or rangefinder to mirrorless adapters as well.

I’ve seen it written that you can’t be sure whether or not your adapters are even thickness all the way around, but with this technique, you can make sure that your adapters are perfect.

Carlo originally posted this as a thread on the forums but I thought it would be useful as a post. He has graciously allowed us to re-publish it here. –Pat

jpeg2RAW Guest Spot

An interview! LGM update! And Github?

Mike Howard, the host and creator of the jpeg2RAW podcast reached out to me last week to see if I might be able to come on the show to talk about Free Software Photography and what we’ve been up to here. One of the primary reasons for creating this site was to be able to raise awareness of the Free Software community to a wider audience.

So this is a great opportunity for us to expose ourselves!

Exposing Ourselves

The podcast airs live this Tuesday, February 23^rd at 8PM Eastern (-0500). You can join us at the jpeg2RAW live podcast page! Mike has the live feed available to watch on that page and also has a chat server set up so viewers can interact with us live during the broadcast.

If you are free on Tuesday night then come on by and join us! I’ll be happy to field any questions you want answered (and that Mike asks) and will do my best to not embarrass myself (or our community). If you would like to make sure I address something in particular (or just don’t forget something), I also have a thread on discuss where you can make sure I know it.

I’m also looking for community members to submit some photos to help highlight our work and what’s possible with Free Software. Feel free to link them in the same thread as above. I’ve already convinced andabata to point us to some of his great macro shots (like that awesome lede image) and I’ll be submitting a few of my own images as well. If you have some works that you’d like to share please let me know!

In Case You Miss It

Mike has all of his prior podcasts archived on his Podcasts page. So if you miss the live show it looks like you’ll be able to catch up later at your convenience.

LGM Update

As mentioned previously we are heading to London for Libre Graphics Meeting 2016! We’ve got a flat rented for a great crew to be able to stay together and we’re on track for a PIXLS meet up before LGM!

Speaking of people, I’m looking forward to being able to spend some time with some great folks again this year! We’ve got Tobias, Johannes, and Pascal making it out (I’m not sure that Simon, top below, will be making it out) from darktable, DrSlony and qogniw from RawTherapee, Andrea Ferrero creator of PhotoFlow, even Ofnuts (how cool is that?) may make it out!

We’ve also already had a great response so far on our Pledgie campaign. The campaign is still running if you want to help out!

If anyone is thinking they’d like to make it out to join us, please let me know as soon as possible so we can plan for space!

My friend and model Mairi will also be making it out for the meeting. She’ll be on hand to help us practice lighting setups, model interactions, and will likely be shooting right along with the rest of us as well!

I’ll also be assembling slides for my presentation during LGM. I’ve got a 20 minute time slot to talk about the community we’ve been building here and the neat things our members have been up to (Filmulator, PhotoFlow, and more).

Speaking of slides and sharing information…

Github Organization

I’ve setup a Github Pixls organization so that we can begin to share various things. This came about after talking with @paperdigits on the post about the upcoming podcast at jpeg2RAW. We were talking about ways to share information and assets for creating/delivering presentations about Free Software photography.

At the moment there is only the single repository Presentations as we are figuring out structure. I’ve uploaded my slides and notes from the LGM2015 State of the Libre Graphics presentation announcing PIXLS. If you’re on Github and want to join us just let me know!

Libre Graphics Meeting London

Join us in London for a PIXLS meet-up!

We’re heading to London!

I missed LGM last year in Toronto (having a baby - well, my wife was). I am going to be there this year for LGM/London!

Help Support Us

I don’t ever do this normally, but you’ve got to start somewhere, right?

It’s my long-term desire to be able to hold a PIXLS meetup/event every year where the community can get together. Where we can hold workshops, photowalks, and generally share knowledge and information. For free, for anyone.

For now though, we need support. LGM is a great opportunity for us to meet with many different projects usually having representatives there.

Donations will help us to offset travel costs to attend LGM as well as a pre-LGM meetup we are holding (more below). Anything further will go to creating new content and to cover hosting costs for the site.

Pledgie

I have started a Pledgie campaign to help ease the solicitation of donations:
https://pledgie.com/campaigns/30905

Here’s the fancy little widget they make available:

If you want to help by adding this button places, here’s the code to do it:

<a href='https://pledgie.com/campaigns/30905'>
<img alt='Click here to lend your support to: PIXLS.US at Libre Graphics Meeting 2016 and make a donation at pledgie.com !' src='https://pledgie.com/campaigns/30905.png?skin_name=chrome' border='0' style='width: initial;'>
</a>

Feel free to use it wherever you think it might help. :)

PayPal

You can also donate directly via PayPal if you want:

Awareness

I realize that not everyone will be able to donate funds. No sweat! If you’d still like to help out then perhaps you can help us raise awareness for the campaign? The more folks that know about it the better!

Re-tweeting, blogging, linking, yelling on a street corner all help to raise awareness of what we are doing here. Heck, just invite folks to come read and participate in the community. Let’s help even more people learn about free software!

Come Join Us

Of course, even better if you are able to make your way to London and actually join us at the Libre Graphics Meeting 2016!

The event will be April 15^th — 18^th, hosted by Westminster School of Media Arts and Design, University of Westminster at the Harrow Campus (red marker on the map).

The little checkered flag on the map is for something really neat: a PIXLS meetup!

PIXLS Meet Up

I am going to arrive a day early so that we can have a gathering of PIXLS community folks and anyone else who wants to join us for some photographic fun!

Thanks to the local organizers in London (yay Lara!), we have facilities for us to use. We will be meeting on Thursday, April 14^th at the Furtherfield Commons. The facilities will be available from 1000 – 1800 for us to use.

Furtherfield Commons
Finsbury Gate – Finsbury Park
Finsbury Park, London, N4 2NQ

As near as I can tell, here’s a street view of the Finsbury Gate:

I believe the Commons building is just inside this gate, and on the left.

In 2014 I held a photowalk with LGM attendees in Leipzig the day before the event that was great fun. Let’s expand the idea and do even more!

Here’s a Flickr album of my images from LGM2014 in Leipzig:

This year I plan on bringing a model along to shoot while we are out and about (my friend Mairi if she’s available - or a local model if not). I will also be doing a photowalk again, either in the morning or afternoon.

I am also looking for folks from the community to suggest holding their own photoshoots or workshops, so please step forward and let me know if you’d be interested in doing something! The facilities have bench seating for approximately 20 people, a big desk, and a projector as well.

Three things that I personally will be doing are (in no particular order):

• Natural + flash portraits and model shooting workshop.
• Photowalk around the park + surrounding environs.
• Portraits + architectural photos for Furtherfield (the hosts).

I am hoping to possibly record some of these workshops and interactions for posterity and others that might not be able to make it to London. It might be fun to record some shoots for the community to be able to use!

I am also 100% open to suggestions for content that you, the community, might be interested in seeing. If you have something you’d like me to try (and record), please let me know!

darktable 2.0

An awesome present for the end of 2015!

Sneaking a release out on Christmas Eve, the darktable team have announced their feature release of darktable 2.0! After quite a few months of Release Candidates the 2.0 is finally here. Please join me in saying Congratulations and a hearty Thank You! for all of their work bringing this release to us.

Alex Prokoudine of Libre Graphics World has a more in-depth look at the release including a nice interview with part of the team: Johannes Hanika, Tobias Ellinghaus, Roman Lebedev, and Jeremy Rosen. My favorite tidbit from the interview:

There is a lot less planning involved than many might think.

— Tobias Ellinghaus

Robert Hutton has taken the time to produce a video covering the new features and other changes between 1.6 and 2.0 as well:

A high-level look at the changes and improvements from the release post on the darktable site:

gui:

• darktable has been ported to gtk-3.0
• the viewport in darkroom mode is now dynamically sized, you specify the border width
• side panels now default to a width of 350px in dt 2.0 instead of 300px in dt 1.6
• further hidpi enhancements
• navigating lighttable with arrow keys and space/enter
• brush size/hardness/opacity have key accels
• allow adding tone- and basecurve nodes with ctrl-click
• the facebook login procedure is a little different now
• image information now supports gps altitude

features:

• new print mode
• reworked screen color management (softproof, gamut check etc.)
• delete/trash feature
• pdf export
• export can upscale
• new “mode” parameter in the export panel to fine tune application of styles upon export

core improvements:

• new thumbnail cache replaces mipmap cache (much improved speed, stability and seamless support for even up to 4K/5K screens)
• all thumbnails are now properly fully color-managed
• it is now possible to generate thumbnails for all images in the library using new darktable-generate-cache tool
• we no longer drop history entries above the selected one when leaving darkroom mode or switching images
• high quality export now downsamples before watermark and framing to guarantee consistent results
• optimizations to loading jpeg’s when using libjpeg-turbo with its custom features
• asynchronous camera and printer detection, prevents deadlocks in some cases
• noiseprofiles are in external JSON file now
• aspect ratios for crop&rotate can be added to config file

image operations:

• color reconstruction module
• magic lantern-style deflicker was added to the exposure module (extremely useful for timelapses)
• text watermarks
• shadows&highlights: add option for white point adjustment
• more proper Kelvin temperature, fine-tuning preset interpolation in white balance iop
• monochrome raw demosaicing (for cameras with color filter array physically removed)
• raw black/white point module

packaging:

• removed dependency on libraw
• removed dependency on libsquish (solves patent issues as a side effect)
• unbundled pugixml, osm-gps-map and colord-gtk

generic:

• 32-bit support is soft-deprecated due to limited virtual address space
• support for building with gcc earlier than 4.8 is soft-deprecated
• numerous memory leaks were exterminated
• overall stability enhancements

scripting:

• lua scripts can now add UI elements to the lighttable view (buttons, sliders etc…)
• a new repository for external lua scripts was started: https://github.com/darktable-org/lua-scripts
• it is now possible to edit the collection filters via lua
• it is now possible to add new cropping guides via lua
• it is now possible to run background tasks in lua
• a lua event is generated when the mouse under the cursor changes

The source is available now as well as a .dmg for OS X.
Various Linux distro builds are either already available or will be soon!

Let's Encrypt!

Also a neat 2.5D parallax video for Wikipedia.

I finally got off my butt to get a process in place to obtain and update security certificates using Let’s Encrypt for both pixls.us and discuss.pixls.us. I also did some (more) work with Victor Grigas and Wikipedia to support their #Edit2015 video this year.

Wikipedia #Edit2015

Last year, I did some 2.5 parallax animations for Wikipedia to help with their first-ever end-of-the-year retrospective video (see the blog post from last year). Here is the retrospective from #Edit2014:

So it was an honor to hear from Victor Grigas again this year! This time around there was a neat new crop of images he wanted to animate for the video. Below you’ll find my contributions (they were all used in the final edit, just shortened to fit appropriately):

Here is the final cut of the video, just released today:

Victor chose some really neat images that were fun to work on! Of course, all free software was used in this creation (GIMP for cutting up the images into sections and rebuilding textures as needed and Blender for re-assembling the planes and animating the camera movements). I had previously written a tutorial on doing this with free software on my blog.

You can read more on the wikimedia.org blog!

New Certificates

Yes, this is not very exciting I’ll concede. I think it _is_ important though.

I recently took advantage of my beta invite to Let’s Encrypt. It’s a certificate authority that provides free X.509 certs for domain owners that was founded by the Electronic Frontier Foundation, Mozilla, and the University of Michigan.

The key principles behind Let’s Encrypt are:

• Free: Anyone who owns a domain name can use Let’s Encrypt to obtain a trusted certificate at zero cost.
• Automatic: Software running on a web server can interact with Let’s Encrypt to painlessly obtain a certificate, securely configure it for use, and automatically take care of renewal.
• Secure: Let’s Encrypt will serve as a platform for advancing TLS security best practices, both on the CA side and by helping site operators properly secure their servers.
• Transparent: All certificates issued or revoked will be publicly recorded and available for anyone to inspect.
• Open: The automatic issuance and renewal protocol will be published as an open standard that others can adopt.
• Cooperative: Much like the underlying Internet protocols themselves, Let’s Encrypt is a joint effort to benefit the community, beyond the control of any one organization.

It was relatively painless to obtain the certs. I only had to run their program to use ACME to verify my domain ownership through placing a file on my web root. Once the certs were generated I only had to make some small changes for it to work automatically on https://discuss.pixls.us. (And to automatically get picked up when I update the certs within 90 days).

I still had to manually copy/paste the certs into cpanel for https://pixls.us, though. Not automated (or elegant) but it works and only takes an extra moment to do.

Happy Birthday GIMP!

Also, wallpapers and darktable 2.0 creeps even closer!

I got busy building a birthday present for a project I work with and all sort of neat things happened in my absence! The Ubuntu Free Culture Showcase chose winners for it’s wallpaper contest for Ubuntu 15.10 ‘Wily Werewolf’ (and quite a few community members were among those chosen).

The darktable crew is speeding along to a 2.0 release with a new RC2 being released.

Also, a great big HAPPY 20^th BIRTHDAY GIMP! I made you a present. I hope it fits and you like it! :)

Ubuntu Wallpapers

Back in early September I posted on discuss about the Ubuntu Free Culture Showcase that was looking for wallpaper submissions from the free software community to coincide with the release of Ubuntu 15.10 ‘Wily Werewolf’. The winners were recently chosen from among the submissions and several of our community members had their images chosen!

The winning entries from our community include:

A big congratulations to you all for some amazing images being chosen! If you’re running Ubuntu 15.10, you can grab the ubuntu-wallpapers package to get these images right here!

darktable 2.0 RC2

Hot on the heels of the prior release candidate, darktable now has an RC2 out. There are many minor bugfixes from the previous RC1, such as:

• high iso fix for exif data of some cameras
• various macintosh fixes (fullscreen)
• fixed a deadlock
• updated translations

The preliminary changelog from the 1.6.x series:

• darktable has been ported to gtk-3.0
• new thumbnail cache replaces mipmap cache (much improved speed, less crashiness)
• added print mode
• reworked screen color management (softproof, gamut check etc.)
• removed dependency on libraw
• removed dependency on libsquish (solves patent issues as a side effect)
• unbundled pugixml, osm-gps-map and colord-gtk
• text watermarks
• color reconstruction module
• raw black/white point module
• delete/trash feature
• addition to shadows&highlights
• more proper Kelvin temperature, fine-tuning preset interpolation in WB iop
• noiseprofiles are in external JSON file now
• monochrome raw demosaicing (not sure whether it will stay for release, like Deflicker, but hopefully it will stay)
• aspect ratios for crop&rotate can be added to conf (ae36f03)
• navigating lighttable with arrow keys and space/enter
• pdf export – some changes might happen there still
• brush size/hardness/opacity have key accels
• the facebook login procedure is a little different now
• export can upscale
• we no longer drop history entries above the selected one when leaving dr or switching images
• text/font/color in watermarks
• image information now supports gps altitude
• allow adding tone- and basecurve nodes with ctrl-click
• new “mode” parameter in the export panel
• high quality export now downsamples before watermark and frame to guarantee consistent results
• lua scripts can now add UI elements to the lighttable view (buttons, sliders etc…)
• a new repository for external lua scripts was started.

More information and packages can be found on the darktable github repository.

Remember, updating from the currently stable 1.6.x series is a one-way street for your edits (no downgrading from 2.0 back to 1.6.x).

GIMP Birthday

All together now…

Happy Birthday to GIMP! Happy Birthday to GIMP!…

This past weekend GIMP celebrated it’s 20^th anniversary! It was twenty years ago on November 21^st that Peter Mattis announced the availability of the “General Image Manipulation Program” on comp.os.linux.development.apps.

Twenty years later and GIMP doesn’t look a day older than a 1.0 release! (Yes, there’s a double entendre there).

To celebrate, I’ve been spending the past couple of months getting a brand new website and infrastructure built for the project! Just in case anyone was wondering where I was or why I was so quiet. I like the way it turned out and is shaping up so go have a look if you get a moment!

There’s even an official news post about it on the new site!

GIMP 2.8.16

To coincide with the 20^th anniversary, the team also released a new stable version in the 2.8 series: 2.8.16. Head over to the downloads page to pick up a copy!!

New PhotoFlow Tutorial

Still working hard and fast on PhotoFlow, Andreas took some time to record a new video tutorial. He walks through some basic usage of the program, in particular opening an image, adding layers and layer masks, and saving the results. Have a look and if you have a moment give him some feedback!

Andreas is working on PhotoFlow at a very fast pace, so expect some more news about his progress very soon!

News from the World of Tomorrow

And more awesome updates!

Some awesome updates from the community and activity over on the forums! People have been busy doing some really neat things (that really never fail to astound me). The level of expertise we have floating around on so many topics is quite inspiring.

darktable 2.0 Release Candidate

Towards a Better darktable!

A nice Halloween weekend gift for the F/OSS photo community from darktable: a first Release Candidate for a 2.0 release is now available!

Houz made the announcement on the forums this past weekend and includes some caveats. (Edits will be preserved going up, but it won’t be possible to downgrade back to 1.6.x).

Preliminary notes from houz (and Github):

• darktable has been ported to gtk-3.0
• new thumbnail cache replaces mipmap cache (much improved speed, less crashiness)
• added print mode
• reworked screen color management (softproof, gamut check etc.)
• text watermarks
• color reconstruction module
• raw black/white point module
• delete/trash feature
• addition to shadows&highlights
• more proper Kelvin temperature, fine-tuning preset interpolation in WB iop
• noiseprofiles are in external JSON file now
• monochrome raw demosaicing (not sure whether it will stay for release, like Deflicker, but hopefully it will stay)
• aspect ratios for crop&rotate can be added to conf (ae36f03)
• navigating lighttable with arrow keys and space/enter
• pdf export – some changes might happen there still
• brush size/hardness/opacity have key accels
• the facebook login procedure is a little different now
• export can upscale
• we no longer drop history entries above the selected one when leaving dr or switching images
• text/font/color in watermarks
• image information now supports gps altitude
• allow adding tone- and basecurve nodes with ctrl-click
• we renamed mipmaps to thumbnails in the preferences
• new “mode” parameter in the export panel
• high quality export now downsamples before watermark and frame to guarantee consistent results
• lua scripts can now add UI elements to the lighttable view (buttons, sliders etc…)
• a new repository for external lua scripts was started.

G’MIC 1.6.7

Because apparently David Tschumperlé doesn’t sleep, a new release of G’MIC was recently announced as well! This release includes a really neat new patch-based texture resynthesizer that David has been playing with for a while now.

It will build an output texture of arbitrary size based on an input texture (and can result in some neat looking peppers apparently).

Speaking of G’MIC…

G’MIC for Adobe After Effects and Premier Pro

Yes, I know it’s Adobe. Still, I can’t help but think that this might be an awesome way to introduce some people to the amazing work being done by so many F/OSS creators.

Tobias Fleischer announced on this post that he has managed to get G’MIC working with After Effects and Premier Pro. Even some of the more intensive filters like skeleton and Rodilius appear to be working fine (if a bit sluggish)!

PhotoFlow

You might remember PhotoFlow as the project that creator Andrea Ferrero used when writing his Blended Panorama Tutorial from a few months ago. What you might not realize is that Andrea has also been working at a furious pace improving PhotoFlow (indeed it feels like every few days he is announcing new improvements - almost as fast as G’MIC!).

His latest release was announced a few days ago as 0.2.3. He’s incorporated some nice new improvements in this version:

• the additon of the LMMSE demosaicing method, directly derived from the algorithm implemented in RawTherapee
• an impulse noise (also known as salt&pepper) reduction tool, again derived from rawTherapee. It effectively reduces isolated bright and dark pixels.
• a perspective correction tool, derived from Darktable. It can simultaneously correct horizontal and vertical perspective as well as tilting, and works interactively.

Head on over to the PhotoFlow Blog to check things out!

LightZone 4.1.3 Released

We don’t hear as often from folks using LightZone, but that doesn’t mean they’re not working on things! In fact, Doug Pardee just stopped by the forums a while ago to announce a new release is available, 4.1.3. (Bonus fun - read that topic to see the Revised BSD License go flying right over my head!)

Head over to [their announcement] to see what they’re up to. [their announcement]: http://lightzoneproject.org/content/september-27-2015-lightzone-v413-now-available

Rapid Photo Downloader

We also had the developer of Rapid Photo Downloader, Damon Lynch, stop by the forums to solicit feedback from users just the other day. A nice discussion ensued and is well worth reading (or even contributing to!).

Damon is working hard on the next release of RPD (apparently the biggest update since the projects inception in 2007!), so go show some support and provide some feedback for him.

RawTherapee Forum

The RawTherapee team is testing out having a forum over here on discuss as well (we welcomed the G’MIC community a little while ago). This is currently an alternate forum for the project (which may become the official forum in the future). The category is quiet as we only just set it up, so drop by and say hello!

Speaking of RawTherapee…

Lede Image

I want to thank Morgan Hardwood (LondonLight.org) for providing us a wonderful view of Röstånga, Sweden as a background image on the main page.

Portrait Lighting Cheat Sheets

Blender to the Rescue!

Many moons ago I had written about acquiring a YN-560 speedlight for playing around with off-camera lighting. At the time I wanted to experiment with how different modifiers might be used in a portrait setting. Unfortunately, these were lighting modifiers that I didn’t own yet.

I wasn’t going to let that slow me down, though!

If you want to skip the how and why to get straight to the cheat sheets, click here.

Infinite Realities had released a full 3D scan by Lee Perry-Smith of his head that was graciously licensed under a Creative Commons Attribution 3.0 Unported License. For reference, here is a link to the object file and textures (80MB) and the displacement maps (65MB) from the Infinite Realities website.

What I did was to bring the high resolution scan and displacement maps into Blender and manually created my lights with modifiers in a virtual space. Then I could simply render what a particular light/modifier would look like with a realistic person being lit in any way I wanted.

This leads to all sorts of neat freedom to experiment with things to see how they might come out. Here’s another look at the lede image:

I had originally intended to make a nice bundled application that would allow someone to try all sorts of different lighting setups, but my skill in Blender only go so far. My skills at convincing others to help me didn’t go very far either. :)

So, if you’re ok with navigating around Blender already, feel free to check out my original blog post to download the .blend file and give it try! Jimmy Gunawan even took it further and modified the .blend to work with Blender cycles rendering as well.

With the power to create a lighting visualization of any scenario I then had to see if there was something cool I could make for others to use…

The Lighting Cheat Sheets

I couldn’t help but generate some lighting cheat sheets to help others use as a reference. I’ve seen some different ones around but I took advantage of having the most patient model in the world to do this with. :)

These were generated by rotating a 20” (virtual) softbox in a circle around the subject at 3 different elevations (0, 30°, and 60°).

Click the caption title for a link to the full resolution files:

Hopefully these might prove useful as a reference for some folks. Share them, print them out, tape them to your lighting setups! :) I wonder if we could get some cool folks from the community to make something neat with them?

Softness and Superresolution

Experimenting and Clarifying

A small update on how things are progressing (hint: well!) and some neat things the community is playing with.

I have been quiet these past few weeks because I decided I didn’t have enough to do and thought a rebuild/redesign of the GIMP website would be fun, apparently. Well, it _is_ fun and something that couldn’t hurt to do. So I stepped up to help out.

A Question of Softness

There was a thread recently on a certain large social network in a group dedicated to off-camera flash. The thread was started by someone with the comment:

The most important thing you can do with your speed light is to put some rib [sic] stop sail cloth over the speed light to soften the light.

Which just about gave me an aneurysm (those that know me and lighting can probably understand why). Despite some sound explanations about why this won’t work to “soften” the light, there was a bit of back and forth about it. To make matters worse, even after over 100 comments, nobody bothered to just go out and shoot some sample images to see it for themselves.

So I finally went out and shot some to illustrate and I figured they would be more fun if they were shared (I did actually post these on our forum).

I quickly set a lightstand up with a YN560 on it pointed at my garden statue. I then took a shot with bare flash, one with diffusion material pulled over the flash head, and one with a 20” diy softbox attached.

Here’s what the setup looked like with the softbox in place:

Remember, this was done to demonstrate that simply placing some diffusion fabric over the head of a speedlight does nothing to “soften” the resulting light:

This shows clearly that diffusion material over the flash head does nothing to affect the “softness” of the resulting light.

For a comparison, here is the same shot with the softbox being used:

I also created some crops to help illustrate the difference up close:

Hopefully this demonstration can help put to rest any notion of softening a light through close-set diffusion material (at not-close flash-to-subject distances). At the end of the day, the “softness” quality of a light is a function of the apparent size of the light source relative to the subject. (The sun is the biggest light source I know of, but it’s so far it’s quality is quite harsh.)

A Question of Scaling

On discuss, member Mica asked an awesome question about what our workflows are for adding resolution (upsizing) to an image. There were a bunch of great suggestions from the community.

One I wanted to talk about briefly I thought was interesting from a technical perspective.

Both Hasselblad and Olympus announced not too long ago the ability to drastically increase the resolution of images in their cameras that used a “sensor-shift” technology to shift the sensor by a pixel or so while shooting multiple frames, then combing the results into a much larger megapixel image (200MP in the case of Hasselblad, and 40MP in the Olympus).

It turns out we can do the same thing manually by burst shooting a series of images while handholding the camera (the subtle movement of our hand while shooting provides the requisite “shift” to the sensor). Then we simply combine the images, upscale, and average the results to get a higher resolution result.

The basic workflow uses Hugin align_image_stack, Imagemagick mogrify, and G’MIC mean blend script to achieve the results.

1. Shoot a bunch of handheld images in burst mode (if available).
2. Develop raw files if that’s what you shot.
3. Scale images up to 4x resolution (200% in width and height). Straight nearest-neighbor type of upscale is fine.
   • In your directory of images, create a new sub-directory called resized.
   • In your directory of images, run mogrify -scale 200% -format tif -path ./resized *.jpg if you use jpg’s, otherwise change as needed. This will create a directory full of upscaled images.
4. Align the images using Hugin’s align_image_stack script.
   • In the resized directory, run /path/to/align_image_stack -a OUT file1.tif file2.tif ... fileX.tif The -a OUT option will prefix all your new images with OUT.
   • I move all of the OUT* files to a new sub-directory called aligned.
5. In the aligned directory, you now only need to mean average all of the images together.
   • Using Imagemagick: convert OUTfile*.tif -evaluate-sequence mean output.bmp
   • Using G’MIC: gmic video-avg.gmic -avg \" *.tif \" -o output.bmp

I used 7 burst capture images from an iPhone 6+ (default resolution 3264x2448). This is the test image:

Here is a 100% crop of the first area:

The second area crop:

Obviously this doesn’t replace the ability to have that many raw pixels available in a single exposure, but if the subject is relatively static this method can do quite well to help increase the resolution. As with any mean/median blending technique, a nice side-effect of the process is great noise reduction as well…

Not sure if this warrants a full article post, but may consider it for later.

Notes from the dark(table) Side

A review of the Open Source Photography Course

We recently posted about the Open Source Photography Course from photographer Riley Brandt. We now also have a review of the course as well.

This review is actually by one of the darktable developers, houz! He had originally posted it on discuss as a topic but I think it deserves a blog post instead. (When a developer from a favorite project speaks up, it’s usually worth listening…)

Here is houz’s review:

The Open Source Photography Course Review

by houz

It seems that there is no topic to discuss The Open Source Photography Course yet so let’s get started.

Disclaimer

First of all, as a darktable developer I am biased so take everything I write with a grain of salt. Second, I didn’t pay for my copy of the videos but Riley was kind enough to provide a free copy for me to review. So add another pinch of salt. I will therefore not tell you if I would encourage you to buy the course. You can have my impressions nevertheless.

Review

I won’t say anything about the GIMP part, not because it wouldn’t know how to use that software but it’s relatively short and I just didn’t notice anything to comment on. It’s solid basics of how to use GIMP and the emphasis on layer masks is really important in real world usage.

Now for the darktable part, I have to say that I liked it a lot. It showcases a viable workflow and is relatively complete – not by explaining every module and becoming the audio book of the user manual but by showing at least one tool for every task. And as we all know, in darktable there are many ways to skin a cat, so concentrating on your favourites is a good thing.

What I also appreciate is that Riley managed to cut the single topics to manageable chunks of around 10 minutes or less so you can easily watch them in your lunch break and have no problem to come back to one topic later and easily find what you are looking for.

Before this starts to sound like an advertisement I will just point out some small nitpicking things I noticed while watching the videos. Most of these were not errors in the videos but are just extra bits of information that might make your workflow even smoother, so it’s more of an addendum than an erratum.

• When going through your images on lighttable you can either zoom in till you only see a single image (alt-1 is a shortcut for that) or hold the z key pressed. Both are shown in the videos. The latter can quickly become tedious since releasing z just once bring you back to where you were. There are however two more keyboard shortcuts that are not assigned by default under views>lighttable: ‘sticky preview’ and ‘sticky preview with focus detection’. Both work just like normal z and ctrl-z, just without the need to keep the key pressed. You can assign a key to these, for example by reusing z and ctrl-z.
• Color labels can be set with F1 .. F5, similar to rating.
• Basecurve and tonecurve allow very fine up/down movement of points with the mouse wheel. Hover over a node and scroll.
• Gaussian in shadows&highlights tends to give stronger halos than bilateral in normal use, see the darktable blog for an example.
• For profiled denoising better use ‘HSV color’ instead of ‘color’ and ‘HSV lightness’ instead of ‘lightness’, see the user manual for details.
• When using the mouse wheel to zoom the image you can hold ctrl to get it smaller than fitting to the screen. That’s handy to draw masks over the image border.
• When moving the triangles in color zones apart you actually widen the scope of affected values since the curve gets moved off the center line on a wider range.
• Also color zones: You can also change reds and greens in the same instance, no need for multiple instances. Riley knows that and used two instances to be able to control the two changes separately.
• When loading sidecar files from lighttable, you can even treat a JPEG that was exported from darktable like an XMP file and manually select that since the JPEGs get the processing data embedded. It’s like a backup of the XMP with a preview. Caveat: When using LOTS of mask nodes (mostly with the brush mask) the XMP data might get too big so it’s no longer possible to embed in the JPEG, but in general it works.
• The collect module allows to store presets so you can quickly access often used search rules. And since presets only store the module settings and not the resulting image set these will be updated when new images are imported.
• In neutral density you can draw a line with the right mouse button, similar to rotating images.
• Styles can also be created from darkroom, there is a small button next to the history compression button.

So, that’s it from me. Did you watch the videos, too? What was your impression? Do you have any remarks?

New Discuss Categories and Logging In

Software, Showcase, and Critiques. Oh My!

Hot on the heels of our last post about welcoming G’MIC to the forums at discuss.pixls.us, I thought I should speak briefly about some other additions I’ve recently made.

These were tough for me to finally make a decision about. I want to be careful and not get crazy with over-categorization. At the same time, I do want to make good logical breakdowns for people that is still intuitive.

Here is what the current category breakdown looks like for discuss:

• PIXLS.US
  The comment/posts from articles/blogposts here on the main site.
• Processing
  Processing and managing images after they’ve been captured.
• Capturing
  Capturing an image and the ways we go about doing it.
• Showcase
• Critique
• Meta
  Discussions related to the website or the forum itself.
  • Help!
    Help with the website or forums.
• Software
  Discussions about various software in general.
  • G’MIC
    Topics all about G’MIC.

Along with the addition of the Software category (and the G’MIC subcategory), I decided that the Help! category would make more sense under the Meta category. That is, the Help! section is for website/forum help, which is more of a Meta topic (hence moving it).

Software

As we’ve already seen, there is now a Software category for all discussions about the various software we use. The first sub-category to this is of course, the G’MIC subcategory.

If there is enough interest in it, I am open to creating more sub-categories as needed to support particular software projects (GIMP, darktable, RawTherapee, etc…). I will wait until there is some interest before adding more categories here.

Showcase

This category had some interest from members and I agree that it’s a good idea. It’s intended as a place for members to showcase the works they’re proud of and to hopefully serve as a nice example of what we’re capable of producing using F/OSS tools.

A couple of examples from the Showcase category so far:

There may be a use of this category later for storing submissions for a rotating lede image on the main page of the site.

Critique

This is intended as a place for members to solicit advice and critiques on their works from others. It took me a little work to come up with an initial take on the overall description for the category.

I can promise that I will do my best to give honest and constructive feedback to anyone that asks in this category. I also promise to do my best to make sure that no post goes un-answered here (I know how beneficial feedback has been to me in the past, so it’s the least I could do to help others out in return).

Discuss Login Options

I also bit the bullet this week and finally caved to sign up for a Facebook account. The only reason was because I had to have a personal account to get an API key to allow people to log in using their FB account (with OAuth).

On the other hand, we now accept four different methods of logging in automatically along with signing up for a normal account. I have been trying to make it as frictionless as possible to join the conversation and hopefully this most recent addition (FB) will help in some small way.

Oh, and if you want to add me on Facebook, my profile can be found here. I also took the time to create a page for the site here: PIXLS.US on Facebook.

Welcome G'MIC

Moving G'MIC to a modern forum

Anyone who’s followed me for a while likely knows that I’m friends with G’MIC (GREYC’s Magic for Image Computing) creator David Tschumperlé. I was also able to release all of my film emulation presets on G’MIC for everyone to use with David’s help and we collaborated on a bunch of different fun processing filters for photographers in G’MIC (split details/wavelet decompose, freaky details, film emulation, mean/median averaging, and more).

It’s also David that helped me by writing a G’MIC script to mean average images for me when I started making my amalgamations (Thus moving me away from my previous method of using Imagemagick):

So when the forums here on discuss.pixls.us were finally up and running, it only made sense to offer G’MIC its own part of the forums. They had previously been using a combination of Flickr groups and gimpchat.com. These are great forums, they were just a little cumbersome to use.

You can find the new G’MIC category here. Stop in and say hello!

I’ll also be porting over the tutorials and articles on work we’ve collaborated on soon (freaky details, film emulation).

Congratulations

To the winners of the Open Source Photography Course Giveaway

I compiled the list of entries this afternoon across the various social networks and let random.org pick an integer in the domain of all of the entries…

So a big congratulations goes out to:

Denny Weinmann (Facebook, @dennyweinmann, Google+ )
and
Nathan Haines (@nhaines, Google+)

I’ll be contacting you shortly (assuming you don’t read this announcement here first…)! I will need a valid email address from you both in order to send your download links. You can reach me at pixlsus@pixls.us.

Thank you to everyone who shared the post to help raise awareness! The lessons are still on sale until August 1^st for $35USD over on Riley’s site.

The Open Source Photography Course

A chance to win a free copy

Photographer Riley Brandt recently released his Open Source Photography Course. I managed to get a little bit of his time to answer some questions for us about his photography and the course itself. You can read the full interview right here:

A Q&A with Photographer Riley Brandt

As an added bonus just for PIXLS.US readers, he has gifted us a nice surprise!

Did Someone Say Free Stuff?

Riley went above and beyond for us. He has graciously offered us an opportunity for 2 readers to win a free copy of the course (one in an open format like WebM/VP8, and another in a popular format like MP4/H.264)!

For a chance to win, I’m asking you to share a link to this post on:

• Twitter
• Google+
• Facebook

with the hashtag #PIXLSGiveAway (you can click those links to share to those networks). Each social network counts as one entry, so you can triple your chances by posting across all three.

Next week (Monday, 2015-07-20 Wednesday, 2015-07-22 to give folks a full week), I will search those networks for all the posts and compile a list of people, from which I’ll pick the winners (using random.org). Make sure you get that hashtag right! :)

Some Previews

Riley has released three nice preview videos to give a taste of what’s in the courses:

darktable on Windows

Why don't you provide a Windows build?

Due to the heated debate lately, a short foreword:

We do not want to harass, insult or criticize anyone due to his or her choice of operating system. Still, from time to time we encounter comments from people accusing us of ignorance or even disrespect towards Windows users. If any of our statements can be interpreted such, we want to apologize for that – and once more give the full explanation of our lacking Windows support.

The darktable project

darktable is developed and maintained by a small group of people in their spare time, just for fun. We do not have any funds, do not provide travel reimbursements for conferences or meetings, and don’t even have a legal entity at the moment. In other words: None of the developers has ever seen (and most likely will ever see) a single $(INSERT YOUR CURRENCY) for the development of darktable, which is thus a project purely driven by enthusiasm and curiosity.

The development environment

The team is quite mixed, some have a professional background in computing, others don’t. But all love photography and like exploring the full information recorded by the camera themselves. Most new features are added to darktable as an expert for, let’s say GPU computing, steps up and is willing to provide and maintain code for the new feature.

Up till now there is one technical thing that unites all developers: None of them is using Windows as operating system. Some are using Mac OSX, Solaris, etc, but most run some Linux distribution. New flavors of operating systems kept being added to our list with people willing to support their favorite system joining the team.

Also (since this stands out a bit as “commercial operating system”) Mac OS X support arrived in exactly this way. Someone (parafin!) popped up, said: “I like this software, and I want to run darktable on my Mac.”, compiled it on OS X and since then does testing and package building for the Mac OS X operating system. And this is not an easy job. Initially there were just snapshot builds from git, no official releases, not even release candidates – but already the first complaints about the quality arrived. Finally, there was a lot of time invested in working around specific peculiarities of this operating system to make it work and provide builds for every new version of darktable released.

This nicely shows one of the consequences of the project’s organizational (non-) structure and development approach: at first, every developer cares about darktable running on his personal system.

Code contributions and feature requests

Usually feature requests from users or from the community are treated like a brainstorming session. Someone proposes a new feature, people think and discuss about it – and if someone likes the idea and has time to code it, it might eventually come – if the team agrees on including the feature.

But life is not a picnic. You probably wouldn’t pass by your neighbor and demand from him to repair your broken car – just because you know he loves to tinker with his vintage car collection at home.
Same applies here. No one feels comfortable if suddenly request are being made that would require a non-negligible amount of work – but with no return for the person carrying out the work, neither moneywise nor intellectually.

This is the feeling created every time someone just passes by leaving as only statement: “Why isn’t there a Windows build (yet)?”.

Providing a Windows build for darktable

The answer has always been the same: because no one stepped up doing it. None of the passers-by requesting a Windows build actually took the initiative, just downloaded the source code and started the compilation. No one approached the development team with actual build errors and problems encountered during a compilation using MinGW or else on Windows. The only thing ever aired were requests for ready-made binaries.

As stated earlier here, the development of darktable is totally about one’s own initiative. This project (as many others) is not about ordering things and getting them delivered. It’s about starting things, participating and contributing. It’s about trying things out yourself. It’s FLOSS.

One argument that pops up from time to time is: “darktable’s user base would grow immensely with a Windows build!”. This might be true. But – what’s the benefit from this? Why should a developer care how many people are using the software if his or her sole motivation was producing a nice software that he/she could process raw files with?

On the contrary: more users usually means more support, more bug tracker tickets, more work. And this work usually isn’t the pleasing sort, hunting seldom bugs occurring with some rare camera’s files on some other operating system is usually not exactly what people love to spent their Saturday afternoon on.

This argumentation would totally make sense if darktable would be sold, the developers paid and the overall profit would depend on the number of people using the software. No one can be blamed for sending such requests to a company selling their software or service (for your money or your data, whatever) – and it is up to them to make an economical decision on whether it makes sense to invest the time and manpower or not.

But this is different.

Not building darktable on Windows is not a technical issue after all. There certainly are problems of portability, and code changes would be necessary, but in the end it would probably work out. The real problem is (as has been pointed out by the darktable development team many times in the past) the maintenance of the build as well as all the dependencies that the package requires.

The darktable team is trying to deliver a high-quality reliable software. Photographers rely on being able to re-process their old developments with recent versions of darktable obtaining exactly the same result – and that on many platforms, being it CPUs or GPUs with OpenCL. Satisfying this objective requires quite some testing, thinking and maintenance work.

Spawning another build on a platform that not a single developer is using would mean lots and lots of testing – in unfamiliar terrain, and with no fun attached at all. Releasing a half-way working, barely tested build for Windows would harm the project’s reputation and diminish the confidence in the software treating your photographs carefully.

We hope that this reasoning is comprehensible and that no one feels disrespected due to the choice of operating system.

References

That other OS

PhotoFlow Blended Panorama Tutorial

Andrea Ferrero has been busy!

After quite a bit of back and forth I am quite happy to be able to announce that the latest tutorial is up: A Blended Panorama with PhotoFlow! This contribution comes from Andrea Ferrero, the creator of a new project: PhotoFlow.

In it, he walks through a process of stitching a panorama together using Hugin and blending multiple exposure options through masking in PhotoFlow (see lede image). The results are quite nice and natural looking!

Local Contrast Enhancement: Gaussian vs. Bilateral

Andrea also runs through a quick video comparison of doing LCE using both a Gaussian and Bilateral blur, in case you ever wanted to see them compared side-by-side:

He started a topic post about it in the forums as well.

Thoughts on the Main Page

Over on discuss I started a thread to talk about some possible changes to the main page of the site.

Specifically I’m talking about the background lede image at the very top of the main page:

I had originally created that image as a placeholder in Blender. The site is intended as a photography-centric site, so the natural thought was why not use photos as a background instead?

The thought is to rotate through images as provided by the community. I’ve also mocked up two version of using an image as a background.

Simple replacement of the image with photos from the community. This is the most popular in the poll on the forum at the moment. The image will be rotated amongst images provided by community members. I just need to make sure that the text shown is legible over whatever the image may be…

Full viewport splash version, where the image fills the viewport. This is not very popular from the feedback I received (thank you akk, ankh, muks, DrSlony, LebedevRI, and others on irc!). I personally like the idea but I can understand why others may not like it.

If anyone wants to chime in (or vote in the poll) then head over to the forum topic and let us know your thoughts!

Also, a big thank you to Morgan Hardwood for allowing us to use that image as a background example. If you want a nice way to support F/OSS development, it just so happens that Morgan is a developer for RawTherapee, and a print of that image is available for purchase. Contact him for details.

Interesting Usertest and Incoming

A view of someone using the site and contributing

I ran across a neat website the other day for getting actual user feedback when viewing your website: UserTesting. They have a free option called peek that records a short (~5 min.) screencast of a user visiting the site and narrating their impressions.

You can imagine this to be quite interesting to someone building a site.

It appears the service asks its testers to answer three specific questions (I am assuming this is for the free service mainly):

• What is your first impression of this web page? What is this page for?
• What is the first thing you would like to do on this page? Please go ahead and try to do that now. Please describe your experience.
• What stood out to you on this website? What, if anything, frustrated you about this site? Please summarize your thoughts regarding this website.

Here’s the actual video they sent me (can also be found on their website):

I don’t have much to say about the testing. It was very insightful and helpful to hear someones view coming to the site fresh. I’m glad that my focus on simplicity is appreciated!

It was interesting that the navigation drawer wasn’t used, or found, until the very end of the session. It was also interesting to hear the testers thoughts around scrolling down the main page (is it so rare these days for content to be longer than a single screen - above the fold?).

Exposure Blended Panorama Coming Soon

The creator of new processing project PhotoFlow, Andrea Ferrero, is being kind enough to take a break from coding to write a new tutorial for us: “Exposure Blended Panoramas with Hugin and Photoflow”!

I’ve been collaborating with him on getting things in order to publish and this looks like it’s going to be a fun tutorial!

Submitting

We’ve been talking back and forth trying to find a good workflow for contributors to be able to provide submissions as easily as possible. At the moment I translate any submissions into Markdown/HTML as needed from whatever source the author decides to throw at me. This is less than ideal (but at least it’s nice and easy for authors - which is more important to me than having to port them manually).

Github Submissions

For those comfortable with Git and Github I have created a neat option to submit posts. You can fork my PIXLS.US repository from here:

https://github.com/patdavid/PIXLSUS

Just follow the instructions on that page, and issue a pull request when you’re done. Simple! :) You may want to communicate with me to let me know the status of the submission, in case you’re still working on it, or it’s ready to be published.

Any Old Files

Of course, if you want to submit some content, please don’t feel you have to use Github if you’re not comfortable with it. Feel free to write it any way that works best for you (as I said, my native build files are usually simple Markdown). You can also reach out to me and let me know what you may be thinking ahead of time, as I might be able to help out.

A New (Old) Tutorial

Revisiting an Open Source Portrait (Mairi)

A little while back I had attempted to document a shoot with my friend and model, Mairi. In particular I wanted to capture a start-to-finish workflow for processing a portrait using free software. There are often many tutorials for individual portions of a retouching process but rarely do they get seen in the context of a full workflow.

The results became a two-part post on my blog. For posterity (as well as for those who may have missed it the first time around) I am republishing the second part of the tutorial Postprocessing here.

Though the post was originally published in 2013 the process it describes is still quite current (and mostly still my same personal workflow). This tutorial covers the retouching in post while the original article about setting up and conducting the shoot is still over on my personal blog.

The tutorial may read a little long but the process is relatively quick once it’s been done a few times. Hopefully it proves to be helpful to others as a workflow to use or tweak for their own process!

Coming Soon

I am still working on getting some sample shots to demonstrate the previously mentioned noise free shadows idea using dual exposures. I just need to find some sample shots that will be instructive while still at least being something nice to look at…

Also, another guest post is coming down the pipes from the creator of PhotoFlow, Andrea Ferrero! He’ll be talking about creating blended panorama images using Hugin and PhotoFlow. Judging by the results on his sample image, this will be a fun tutorial to look out for!

Software and Noise

Wonderful response from everyone

I want to take a moment to thank everyone for all of the kind words and support over the past week. A positive response can be a great motivator to help keep the momentum rolling (and everyone really has been super positive)!

Software

The Software page is live with a decent start at a list.

I posted an announcement of the site launch over on reddit and one of the comments (from /u/cb900crdr) was that it might be helpful to have a list of links to programs. I had originally planned on having a page to list the various projects but removed it just before launch (until I could find some time to gather all the links).

This was as good a reason as any to take a shot at putting a page together. I brought the topic up on the forums to get input from everyone as well. If you see that I’ve missed anything, please consider adding it to the list on the forum.

I think it may be helpful to add at least a sentence or two description to identify what each project does for those not familiar with them. For instance, if you didn’t know what Hugin was before, the name by itself is not very helpful (or GIMP, or G’MIC, etc…). The problem is how to do it without cluttering up the page too much.

Noise

I had also mentioned in this post on the forums about a neat method for basically replacing shadow tones in one image with those from second, overexposed image. The approach is similar in theory to tonemapping an HDR and is originally described by Guillermo Luijk (back in 2007).

The process basically exploits the fact that digital sensors have a linear response (a basis for the advice ETTR - “Expose to the Right”). His suggested workflow is to use a second exposure of the scene but exposed +4EV. Then to adjust the exposure of the second image down -4EV and then replace the shadow tones in the base image with the adjusted (noise-reduced) one.

I will write an article soon describing the workflow in a bit more detail. Stay tuned!

Lede image: Unnecessary Noise Prohibited by Jens Schott Knudsen cbn

It's Alive!

Time to finally launch...

Well, here we are. I just checked the first blog post and it was dated August 24^th, 2014. I had probably been working on the back end of the site getting things running for the basic blog setup a few weeks prior to that. It’s almost been a full year since I started working on this idea.

So it is with great pleasure that I can finally say…

Welcome to PIXLS.US!

If you’re just now joining us, let me re-iterate the mission statement for this website.

PIXLS.US Mission Statement

To provide tutorials, workflows and a showcase for high-quality photography using Free/Open Source Software.

I started this site because the world of F/OSS photography is fractured across different places. There’s no good single place for photographers to collaborate around free software workflows, as well as a lack of good tutorials aimed at high-quality processing with free software.

Tutorials

I have personally been writing tutorials on my blog for a few years now (holy crap). I primarily started doing it because while there are many tutorials for photo editing, they almost always stopped short of working towards high-quality results. The few tutorials that did try to address high quality results were all quite a few years old (and often in need of updating).

With your help, I’m hoping to change that here.

Workflows

Workflows is something that doesn’t often get described either. Specifically, what a workflow looks like with free software. For instance, some thoughts off the top of my head:

• Creating a panorama image from start to finish.
• Shooting and editing fashion images.
• Taking great portrait images, and how to retouch them.
• What to watch out for when shooting macro.
• Planning and shooting great astrophotography.
• How to approach landscape editing.
• Creating a composite dream image.

These are just some of the ideas around workflows. It also doesn’t have to be only software-focused. There is a wealth of knowledge about practical techniques that we can all share as well.

Showcase

Quick - name 5 photographers whose work you love, that use free software. Did you have trouble reaching five? That’s another of the things that I would like to focus on here: showcasing amazing work from talented photographers that happen to use free software (and in some cases may be willing to share with us).

I even started a thread on the forum to try and note some amazing photographers. I will try to work through that list and get them to open up and speak with us a bit about their work and process.

By Us, For Us

I am floored by how awesome the community has been. As I mentioned on my blog, the main reason for me to write was to give something back to the community. I learned so much for so long from others before me and the least I could do is try to help others as well.

This community will be what we make it. Come help make it something awesome that we can all be proud of.

Go sign up on the forum and let your voice be heard.

Have an idea for an article? Let me know (in the forums or by email)!

Make Some Noise!

Finally, we are just starting out and are a small community at the moment. If you’re feeling up to it, please consider letting your social circles know that we’re here and what we’re trying to do. The only way for the community to grow is for people to know it’s here in the first place!

What's In Your Bag?

Thoughts on a next article as well

That lede image above is a quick (and dirty) snapshot of my go-to bag for running out the door. I thought it might be fun to take a diversion and talk about gear a little bit. Here’s the full image again:

I had decided years ago on going with Micro Four Thirds (MFT) as a camera system because I like to travel light, and wanted options to adapt old lenses. (On a side note, I’m still angry that there is not focus-peaking on the E-M5…)

My camera is the Olympus OM-D E-M5 (usually paired with the 12-50mm weatherproof lens when I’m out and about). This is a perfect combination for me, particularly when I’m chasing around a 4 year old in who-knows-where situations. A water and dust resistant lens/body is nice to have.

On the far left is a Promaster 5-in-1 reflector (41 inch). These are usually relatively inexpensive and absolutely indispensable pieces of gear that can be adapted to many different situations.

I was recently reminded of this yet again while on a walk through some gardens…

The base of the reflector (without its covering) is a great translucent scrim that is handy to use with flashes if you need to soften things up a bit (and not lug around a softbox).

Speaking of flashes, you’ll also find my pair of Yongnuo YN-560 manual speedlights. I’ve been slowly teaching myself lighting with speedlights, so rarely will I not have them with me. To use them off-camera I also have a pair of Cactus V5 transceivers (one to transmit, one to receive).

Everything (except the reflector) packs nice and neatly into my wife’s old camera bag (a precursor to the Domke bags) that I ran off with. (That is, the old camera bag of my wife, not the old bag, my wife).

The bag is canvas and I waxed it myself to give it some water resistance. This basically consisted of me melting some wax and brushing it all over the bag, then using a hairdryer to further melt it into the fibers. This was a great DIY project that was relatively inexpensive (about $8USD for more wax than you’ll need) and relatively quick to do (just a few hours total).

Share Your Gear

I’d love to see what others are using out there! Take a minute, snap a photo of your gear/bag, and share it with us. Bonus points if you arrange it by knolling.

Sharpening

I was recently poked by someone on the GIMP-Web mailing list to update one of the tutorials on www.gimp.org about sharpening. I thought about it, then decided it may be better just to write some new material from scratch.

I figured why stop there? I might as well make it a fun post here taking a look at what methods we have for sharpening, why you may (or may not) want to use them, and where in the processing pipeline it makes sense. (While still pushing the GIMP specific sharpening thoughts to a separate tutorial there).

If anyone has thoughts around this or just wants to share what they’re doing, please let us know in the comments below.

Back to Writing

Hiccups and Other Things

I took a bit of a break from writing articles to work on getting the forums up and running. We are almost back to a stable enough point that I want to turn my attention back to writing.

I say almost because there are still a few wonky things that I’d like to work out. There is still a little bit of an issue with the comment embeds from the forum for full-blown articles.

SSL and https

One of the reasons for the possibly strange behavior for articles in the forums is that darix convinced me to go ahead and get SSL setup for the domains. So working on it yesterday we got it running for both the main site here, as well as at the forums.

You should notice an indicator in your browser that your connection is over https somewhere (a little green lock?) for this page right now. I’ve set all connections to PIXLS.US to use SSL now (same thing with the forums).

The only drawback was that we uncovered some strange behavior when importing posts into the forum for embedding. If you care, the way things work is that:

1. I publish an RSS feed of all of the content on the site (https://pixls.us/feed.xml if you’re curious).
2. Every hour the forum polls this feed.
3. If there’s new posts, the forum imports them and creates a new topic. This is what you see under the “PIXLS.US” category on the forum.
4. Some small code on each post (on the website) references the forum topic entry to embed as comments.

There have been a couple of strange things going on with importing those posts, but darix resolved most of them. The only thing that is still strange is the article objects themselves, which at the moment show up twice in the forum.

I should not that all of this could very well be caused by my writing the RSS feeds. I know just enough to be dangerous and annoying to those who know better (this should probably be my epitaph).

Here Lies Pat David

He knew just enough to be dangerous and annoy those who knew better…

Fitting!

On the good side, thanks to the efforts of those smarter than I, even though we had some import hiccups, things have continued to run smoothly for the most part. The correct comments were maintained in the correct topic threads, and those were in turn correctly associated with the posts they belonged to (well, blog posts at any rate).

Coming soon(ish) - creating showcase posts!

An Opportunity

To help (and attract) new users!

I think we are at an interesting time for digital imaging. I came across this graph on Petapixel the other day that showed camera sales from 1947 - 2014:

There was explosive growth driven by the Compact Digital market right around 2000. Likely driven by the advent of those inexpensive compact digital cameras and the ubiquity of home computers. It was relatively cheap to get a decent digital camera and the cost per photo suddenly dropped to a previously unheard of amount (compared to shooting film).

This meant that substantially more people were now able to take and share photographs.

That precarious plummet after 2011 seems frightful for the photography industry as a whole, though. The numbers from the graph would seem to indicate that production in 2014 dropped to below the values from 2001.

Petapixel had a follow-up article where photographer Sven Skafisk added in smartphone sales using data from Gartner Inc.:

If that graph doesn’t describe an industry in the throes of change, then I don’t know what does. It looks like the camera industry is less in decline and more about being in a big transition phase.

So What?

So why would this matter? Because now, more than ever, there is a large amount of people who may be interested in learning to process their photographs in some way. As the costs and barrier to entry to photography as a hobby get lower we see more and more people finding the fun and joy of photography.

Couple that with the fact that the modern language of media consumption is primarily visual and I see a great opportunity brewing.

I feel this is important to us as free software users as it gives us an opportunity to help make people aware of free software (and its ideas). New hobbyists will invariably look for an inexpensive way to get started processing photos and will almost always run into various free software projects at some point in the search.

It’s entirely on us as a community to make sure that there will be good resources to learn from. If we do a good enough job, some of those folks will realize that free software more than meets their needs. If we do a really good job, some of those people will become valuable parts of our communities.

Articles Have Comments Now Also

So I have now also enabled the comments for more than just blog posts. They should now be working just fine on full articles as well. So feel free to head over to Ian Hex’s neat Luminosity Masking in darktable tutorial and leave a comment to let him know what you thought of it! (Or any of the other articles, too.)

A Forum

For Discourse, if you will...

After much hard work, that basically consisted of me annoying darix as often as possible, I am glad to say that we finally have a Discourse instance set up! Super Big thank you to darix for all the help!

So What?

What does this mean? For starters, we now have a forum/community in place that we can start building around photography and free software.

A neat side-effect of this forum is that we now also have a way to embed forum threads as comments on posts (only blogposts at the moment - I’ll add them to articles shortly).

At the bottom of any blog post you should now either see a series of conversations happening with a Continue Discussion or a link to Start Discussion. Either of those buttons will take you to the actual forum to continue the conversation. Replies to topics that are tied to posts will show up as a conversation at the bottom of the post (check the bottom of this post).

The site is open and live at the moment (if a bit bare-bones). Feel free to drop by and create an account, comment on things, start new topics, etc. I’m testing things out at the moment to see if I need to possibly bump the server specs in order to handle the loads (most likely). (In the course of writing this, I went ahead and bumped the server RAM to 2GB - so it should run smoothly).

All the Articles

My God, It's Full of Articles

I spent a little time struggling conceptually with how I wanted to categorize the different types of content I am planning for this site. As I had previously noted, I was already done with creating a blog post type of content, and had noted that I was working on how to show tutorials and ‘showcase’ types of posts.

Apparently, I had the answer in mind when I created that graphic last month. If you notice the two other types of content I am working on, Tutorials and Showcase, are both listed as types Articles on the graphic.

Of course. There will only be two distinct types of content from the viewpoint of the site, blogposts and articles. I will then use the features of the static-site generator I use for this site, metalsmith, to manage the content presentation (tutorials, showcase, etc). This will be handled through collections in metalsmith.

So at the end of the day, even though there will be a section of Tutorials and Showcase or whatever else I come up with (or someone else), the bottom line is that the base content object will be an Article.

I like this approach, as it leaves a large amount of flexibility while maintaining a nice sense of simplicity. (Anything that lowers the barrier to writing and publishing material is good in my book).

An Aside on Collections in Metalsmith

This is just a note to myself in case I forget what I was on about with collections.

There are basically two ways of associating an article with a collection, through metadata on the file and through a matching pattern during compile time. Unfortunately, as near as I can tell, you can’t do them both at the same time for the same collection type.

Metadata

Doing it through metadata assocation only requires that in the front-matter of the file, the collection type is called out, like collection: tutorial. For example, here’s a sample of the front-matter for this blog post:

---
date: 2015-03-30T17:31:36-05:00
title: "All the Articles"
sub-title: "My God, It's Full of Articles"
lede-img: "M31 - Adam Evans.jpg"
author: "Pat David"
collection: blogposts
layout: blog-posts.hbt
---

In this case, the post will be added to the collection, blogposts.

Pattern Matching

In the index.js for the site, there’s a section for using collections where a pattern can be specified to add files:

.use( collections({
    articles: {
        pattern: 'articles/*/index.html',
        sortBy: 'date',
        reverse: true
        }
}))

This glob pattern will simply add all the posts in a folder in the articles/ directory to the collection, articles.

In fact, this is actually how I want to collect all articles on the site for archive purposes. I’ll want a page on the site that will list all of the articles that will be published, regardless of further classifications. I feel that it is helpful for people searching for information to have a single page listing of all the material on the site (I did something similar with my blog by adding an archive page).

Happy!

So these pieces sort of falling into place make me happy because it means that I am much closer to having a setup how I would like it to be. I can get started writing these other article types now without worrying as much about the back end.

Rather, I only need to focus on creating the landing pages for the content type (tutorials/, showcase/, etc…). Yay! More time to spend on writing new stuff!

Discourse

I had mentioned it previously, but darix on #darktable has been an immense help in testing out Discourse for me. He has gotten it to a point where it mostly works so the only thing holding me back from getting it rolled out is deciding how/where to host the instance.

If anyone has any thoughts or suggestions, I’m all ears! To use Darix’s discourse, I’ll need openSUSE 13 at least. Otherwise, I could probably buy a droplet on Digital Ocean and host it there for now.

Deep Links

As well as a sort-of look for article/tutorial indexes

I tried to find a good funny reference to Jack Handey here but failed. Which might be a good thing given how the reference likely shows my age…

I have been working on various bits of the site as well as finishing up a long-overdue article. I’ve also been giving some thoughts in general about interesting ways to move forward with some ideas which I will bore you all with shortly.

Deep Linking

A while back I had some thoughts around how best to format long form articles. I finally decided to keep articles entirely on a single page as opposed to breaking them up across multiple pages. Mostly this was because I know I personally hate having to click through too many times just to read an article, and the technique is often used as a cheap means to show more ads to readers.

The problem with single page articles is linking/referencing content at an arbitrary location in the page. The markdown processor I’m using in metalsmith does add a unique heading id to each html heading element, but doesn’t expose the link easily.

So I spent some time recently writing a small metalsmith plugin to do that for me. In the articles you can now get a direct link to a heading section by hovering the mouse pointer over a heading. The link will become visible at the end of the heading (as a link icon):

This lets you now link directly to that section. So I can now link directly to content deep into the page itself, like this link to the Nikki example for skin retouching.

These are the same heading links that are used for the Contents navigation pane on the menu:

This method of exposing a heading link is similar to what you may find on GitHub for instance. So, at least there’s now the ability to deep-link into articles as needed! :)

Skin Retouching with Wavelets

Also, I took a break from this other thing I’m working on to finish writing the Skin Retouching with Wavelet Decompose article.

This poor article has been in the queue for what feels like forever, so it’s nice to finally be able to publish it. This particular article is a combination of many of the previous things I had written around using wavelet scales for retouching work. If you get a chance to read it, I’d love to hear what anyone has to say about it!

Articles Index Page

I’m still experimenting with the look and feel of the articles index page. If you follow that link you’ll see one of the ideas I currently have for laying it out. I’m not 100% sold on this layout yet, as it may get cumbersome with many articles at once.

I may also provide links at the top of the page for particular content (tutorials, showcases, by tag/software, etc…).

Speaking of which, I’m wondering from a content management standpoint if it makes more sense to publish every item on the site as an “article”, then to handle the categorization and display as a function of tags/categories on the posts. Not quite sure just yet. I’ll still need to fiddle with some other layout/organizational ideas.

On Another Note

I finally also fixed the path problem when generating the blog post listing page. I had a problem where locally referenced images for a post (relative to the post directory) didn’t have their paths updated when showing them on the blog index page. So I took some time and repaired it with a small handlebars helper function.

For instance, the Deep Thoughts image at the beginning of this post wasn’t showing correctly from the blog index page before I fixed it.

Some Updates

Yes still writing and working!

I hate when things take me away for a little while, but won’t make any apologies just yet for having little activity here! It’s mostly a one-man show here at the moment so I do beg for some patience as I build things out and get articles together.

Speaking of building things out…

Site Structure

I have been giving some thought to the general site structure lately. I thought it might be fun to talk about it briefly.

My original (and still current) intention for the main piece of content for PIXLS.US is a tutorial. It’s the main type of content I was writing on my blog as well as what I’ve been trying to update on http://www.gimp.org/tutorials. It’s a nice, known quantity…

So I spent my early time building the site focusing on the layout and design of tutorial pages. Fonts, sizes, weights, layout, and more. It’s just the way I think. Plus, if I did a decent job on this layout, I could not worry about fiddling with it later and instead focus on writing.

I finally ended up with a layout that I liked (basically what you’re reading on right now). The problem was, I wanted a bunch of tutorials, not just one!

So with a little work and the help of some contributors (yay Ian Hex!), I was looking at a few different tutorials now for the site. Yay!

The problem now was that I needed to create a nice page to help guide users to the various tutorials. This is still not done…

So here I am at the moment still working on how best to showcase the neat tutorials on an index page of some sort:

I need to find an attractive and usable means of listing the various tutorial articles. So this is one of the things that has been taking up some of my time.

The main page has also been occupying some of my attention, as I’m not 100% sure how to present all the site information (tutorials, blog posts, showcases, etc…). There’s kind of a running theme here I guess.

I’m also going to be trying to produce some “Showcase” type of article posts that will highlight a F/OSS photographer or images.

The blog pages I’ve already finished (it’s what you’re reading now). I’ve also mostly gotten the index pages for the blog in a workable state. I took some time recently to paginate the blog index pages as well so as to not try to load the entire post history on a single page.

To summarize, there are a few things yet to design and code. I’m working on getting them so we can have an actual launch.

• Main Page

  I still need to design and layout how best to show off the site content.

• Tutorial/Articles Page

  This is another page to design and layout. I have some ideas and neat content already written, so this is just designing the page.

• Showcase Pages & Index

  These pages will be functionally the same as the article pages, but the content will focus more on showcasing FL/OSS artists and their works. I’ll categorize these pages differently so I can collect them on their own index page separate from the tutorials.

In Closing…

So, things are moving along (albeit slower than I would like). I’m building the scaffolding for the future, so I don’t feel so rushed. Better to do it well than quick in my opinion.

Contributing

Also, if anyone would like to immortalize themselves on the early pages of an experimental website to bring high quality tutorials and discussions to the the Free/Open Source Imaging world – well then you know where to turn: pat@patdavid.net.

I promise I don’t bite (hard).

Another Article Done

Ian Hex and Luminosity Masks in darktable

2015 seems to be getting started nicely!

Just before the holidays Ian Hex sent me his finished tutorial to post, and I just finished editing it. It’s a wonderful look at using Luminosity Masks in darktable for targeted adjustments. (Parametric masks in darktable-speak). You can find the new tutorial here:

PIXLS.US: Luminosity Masks in darktable

On a side note, I had previously written about doing Luminosity Masks in GIMP on my personal blog, and yes I will be porting that tutorial here a little later!

Still Writing

I am still working on the Wavelet article (I took a break to copyedit Ian’s article). I am continuing my work on that article as well as taking a rudimentary first stab at an article index page (or possibly a variation for a main landing page for the site).

Just need to decide on an attractive and functional layout for presenting the list of articles we have available. I’m also open to suggestions if any of you readers out there have seen something that you think would be appropriate or neat to consider…

I am also open to taking submissions from folks who may have the mental fortitude to write something for the site. Just shoot me any ideas/sketches/outlines you think may be appropriate! (pat@patdavid.net in case you didn’t already have it…)

Still Writing

Yes, things are still moving (slowly) along

It’s been a busy month (+ ½) for me personally. Things have finally settled down so I can get back to writing articles and working on the site.

Wavelets Coming

As I mentioned in the previous post, I’m currently working through a re-write of the various tutorials I had done about using Wavelet Decompose for skin retouching. I’m about ²⁄₃ of the way through it now and expect to have it finished shortly.

Guest Writer Ian Hex

I also previously mentioned that I’ve been reaching out to a few folks to see if they might be interested in writing some articles for the site. I’m extremely pleased to say that Ian Hex is stepping up to the plate with a neat tutorial about darktable that is being written right at this very moment!

If you haven’t had a chance to see Ian’s work I highly recommend stopping by his site at http://lightsweep.co.uk/ to get a gander at some epic images from the UK. I desperately want to hop on a plane and visit after seeing them!

His self-professed mission is:

..to show off the beauty of British landscapes and architecture to the world

and I’d say he’s doing a bang-up job of it so far!

Ian will be writing about Luminosity Masks in darktable. Given his results and body of work I am personally looking forward to this one!

Maybe if we get a good enough response with his post we can convince him to come back and write some more…

Iterating

Minor changes and another tutorial

I’m working my way through some of the suggestions I’ve received from many folks. In particular, the “px” icon in the upper left to slide open the navigation and Table of Contents has been changed to a (hopefully) more familiar ‘hamburger’ icon. I’ll also be testing some other things in the coming weeks as time permits such as having a TOC show up by default in the right ⅓ of the page at the top.

Don’t expect it too soon as I want to focus on writing more content first. I’m aiming for a December-ish timeframe for a more official launch and want to make sure there is a decent amount of material for folks to consume.

The Next Tutorial

Speaking of material, I’m starting work on a tutorial for skin retouching with wavelet decompose. I’ve written about this many times before, but want to port the ideas over here.

I have a few extra thoughts surrounding the use of wavelets as well as some minor changes in my workflow with them that should make a new writeup more interesting (hopefully). I’ll also focus specifically on skin retouching as opposed to some of the other things that can be done with wavelets.

More Support

I have reached out to some of my favorite amazing photographers using F/OSS in their workflows and the response has been overwhelmingly positive. I’ll speak more about the folks in a later post, but I am personally very thankful that they have taken the time to respond and that it’s been so positive!

More Content

First article is done, more to come

I’ve pretty much finished up the first article mentioned in the previous post. There is still a long way to go.

As much as I’d like to believe that “If you build it, they will come”, the reality is that nobody is coming until there is something worth coming for. So I’m working hard on getting good content in place.

I’m also acutely aware that nobody will stay unless good content continues to be published, but that’s for another post.

Next Up

I am thinking the next article that I’ll update/port will be either Luminosity Masks or Skin Retouching. I am also thinking that a port of my older color curves tutorials might be nice as well (particularly using sample points).

That should get me to four good tutorials to start the site with. At that point I can start queueing up the next few asap.

I also wanted to do more than straight single tutorials, though, which brings me to a question.

Types of Content

What types of content would those of you reading this be interested in?

At the moment I’m thinking of 3 main types of articles, with a possible (probable?) fourth:

• Tutorials
• Workflows
• Showcase
• Getting the Shot

A small explanation on what I’m thinking may help here.

Tutorials

These would be similar to the Digital B&W article I’ve already ported. If you’ve read most of my tutorials on my blog, then you’re already familiar with what I’m thinking for these.

These are straight tutorials looking at a single (usually) effect and how to achieve it. The primary focus is on the steps and tools to produce the desired result.

Workflows

I am envisioning a workflow article to be more of a look at the creative process to achieve a final resulting image. This is more along the lines of another previous set of posts I had written about: The Open Source Portrait and the Open Source Headshot.

These articles would focus on all of the steps and tools to arrive at a resulting image. The difference from a tutorial article is that if a tutorial article might explore how to use Wavelet Decompose for skin retouching, a workflow article might include using that technique (among others) to realize a final vision.

Showcase

Showcasing some of the amazing work I see occasionally is important as well, I think. One, the artists doing this great work really do deserve to be talked about and exposed to a wider audience.

Second, great work by F/OSS using artists act as ambassadors for what is possible using these tools. Too often the low opinion of many concerning F/OSS tools is framed by sub-standard work being shown. There are some amazing photographers working with these tools, and my hope is that they can stand as examples to not only showcase F/OSS but also as a bar for others to aim for (and hopefully smash through).

Getting the Shot?

I’m not 100% sure on this yet, but I think I was originally viewing this as a complete workflow from start to finish, including actually shooting. This is more focused on the photographic process in general and things to keep in mind while capturing the shots for processing later.

HDR, lighting, models, clothes, make-up, landscape scouting, locations, etc…

Quick Tips?

I’m not at all sure about this, but the idea is there. Possibly posts that are very short and targeted at a very specific task or function. Something that might not really warrant a long-form article but could still be quickly useful for others.

I am reminded of this due to an old video of mine that I had done quickly for someone on G+ about how to add a watermark over an image.

You can tell why making videos is best left to folks like Rolf…

Forum and Comments

Thanks to darix (once again) over in irc on #darktable for setting up a Discourse instance for me to play with. I have used it previously on boingboing.net, and I rather like what I’ve seen. It also appears that there may be a way to embed thread posts as well, which would be a nice solution for commenting.

Thoughts?

Anyone with any thoughts on this, as usual, feel free to drop me a line and tell me what you think!

Getting Closer

First article is mostly written

Just a quick update on a couple of interesting things.

The first article is almost done being re-written and updated.

I added some functionality to the slide-out menu and am still thinking about the best icon to use.

I also had a nice epiphany when I realized that the styling I had already written to make big videos works great for images as well.

First Test Article

The first article is almost done being ported and formatted. For anyone who’s curious, it’s a long post from the five part series I did on B&W conversion using GIMP (originally published on my blog).

The writing is going a bit slow because I am also feeling out the formatting and a couple of other minor visual things as they relate to a full-blown article. Of course, it doesn’t help that it’s also a really, really long article…

For those of you bothering to read this blog, and who want to take a look at the state of that article, it can be found here: Pixls.us: Digital B&W Conversion (GIMP). Just don’t forget to let me know if anything looks funky, or with any suggestions/comments/criticisms.

Speaking of Long

Speaking of which, one of my first conundrums while working on it was a question of load times vs. convenience. The original article was written as five separate blog posts which kept everything in reasonably bite-sized chunks to digest. The problem is that as a reader I am sometimes annoyed at having to click through multiple pages to read an article and I thought that most readers here might feel the same way.

One of my concerns was load times and rendering speed of large pages. I think I have all the assets set to load as quick as possible above the fold. I’ve tried to optimize all images as much as possible and am making sure to define discrete width and height attributes in the html to help the browser render and not have to reflow (hopefully).

There are still a few optimizations that I have to implement that I haven’t yet (minify javascript and concatenating all my stylesheets for actual delivery), but I have them in the queue to do. Oh, and spritesheets for some assets that I will get around to making soon as well.

So my current thought is to keep the articles to a single page, even if they are long. I am also 100% open to other ideas as well so if you have one feel free to hit me up!

Getting Around

Long pages can be a bit cumbersome to navigate, though. To help make it easier to target relevant information in the page, all of the headings in a page should have a unique id attribute. This means that users will be able to link directly to sections of a long page (this seems to have fallen out of favor with many websites - why?!).

For instance, I can link directly to the previous section of this post by including the id of the element in the url:

http://pixls.us/blog/2014/09/getting-closer/#speaking-of-long

I’m still thinking about the easiest/best way to present this capability to users, but the groundwork is there for the future.

Navigation

I’m not 100% sure this is obvious, but the “px” logo in the upper-left corner of the page should slide out a navigation from the left side of the page (assuming you have javascript enabled in your browser). If you don’t have javascript enabled, then clicking the logo will take you to the footer of the page where the basic navigation links are located.

I’m also considering a re-working of the icon to possibly make it more obvious that it opens a menu. Perhaps something like the “hamburger menu icon” is in order?

The first set of links are the main ones for navigating the site Home, Blog, Articles and Software. Just below that will be the navigation links for the contents of the current page.

For no other reason than I thought it was neat, I also made it so that the background of each of the Table of Contents entries will be a slightly darker color relative to how far along you are in the page/section. In the example above, I have already read Getting Closer and First Test Article, and I am ~75% of the way through the Speaking of Long section of the post.

Unfortunately, this won’t work without javascript enabled. I am still thinking of a way to possibly include the TOC in the page without screwing up the layout too much. Something to play with later I suppose…

Pretty Pictures

At the moment I am using a combination of serving up the images directly from my host, and using Google+ photos. Mostly because I have limited space on my webhost, and I’m not quite sure what the impact will be just yet. I also gain the distributed Google infrastructure for image hosting, which helps I think as images are by far the biggest files to serve for these pages.

I also get on-the-fly image resizing when hosting the images on Google, which is handy while I build things out.

One of the downsides is that the on-the-fly resizing doesn’t produce progressive jpegs, which I thought might help with rendering speeds of large pages (images loading progressively at least show that something is there…).

Wider Images

I think I mentioned it in the previous post The Big Picture that I had done the styling to get images to span the entire width of the page. In that same post I also demonstrated a means for making embedded videos bigger as well. It turned out that the same styling worked great for images as well.

Here is the lede image wrapped in a <figure> tag:

I can re-use the styling for the larger video to automatically make the image much larger and centered on the page:

And, of course, wrapping the <figure> in a <!-- FULL-WIDTH --> tag yields:

This works across mobile as well but I can’t help but feel it is a bit inelegant. It is also dependent on javsacript and I don’t know if there is a simple way around this. At least now, without javascript turned on, everything else still works except toggling to the comparison version.

Before Launch

I’d like to have at least a few good articles ready to go at launch time. As I said, I’m almost finished with the B&W conversion article, but the question is what to migrate next?

I’m thinking that one of the Open-Source Portrait posts would make a nice article to launch with as well, or perhaps an update/re-write of using Wavelet Decompose for skin retouching? If anyone has a preference or suggestion, I’m all ears!

I’m also going to publish an interview with a F/OSS photographer whose work I admire.

Commenting

I still don't have a good solution

First things first. I forgot to actually link to the new About page in my last post. So here it is. As with all things related to the site, any feedback, comments, or criticisms are welcome!

Speaking of feedback, comments, and criticisms, I wanted to write about it for a moment.

First, I want to thank everyone who has taken the time to contact me and provide me feedback on the site. You have no idea how valuable it is to both as a motivator, and as a means to know when something is off. I appreciate and give my full attention to each and every person and idea thrown at me. Thank you!

From the beginning I have been considering how to let everyone interact with the site and posts. It would be so much easier for folks to leave a comment on a page (or forum) directly. Particularly if it allows everyone to view the conversation.

Disqus

One thing I could do relatively easily is just use a third party commenting system, like Disqus. They make it so easy it almost seems silly not to do it. An account, a few lines of javascript, and done.

This method comes with a price, though. A price in both user privacy concerns as well as the fact that comments are no longer mine (pixls.us) to manage and archive. I don’t know that I’m willing to pay that price yet just for convenience.

If anything, I may set it up as a temporary solution while I work on something a little more long term.

Discourse

From what I’ve seen so far, Discourse is the long term solution that I would like to get up and running. It’s also “Yet-Another-Thing” I should thank darix on #darktable for pointing me to.

The only drawback at the moment is that my hosting provider doesn’t have what I need to get it running (relatively easily). There are a couple of options for hosted solutions that I may go with, but I want to focus on getting the content ready to go for an “official” launch before I get too far down that rabbit hole.

Conclusion

Yes, I know there’s a need for having some sort of commenting system available for everyone to participate! I’ll get one running just as soon as I can.

An About Page and Help

A little more about site

I’ve started working a bit on the “About” page for the site. I wanted a place to highlight the mission statement I’m sort of working from:

To provide tutorials, workflows and a showcase for high-quality photography using Free/Open Source Software.

As well as a place to let users know who is behind the scenes working on the site. It’s mostly me at the moment, but I’ve managed to talk someone into helping me…

Enter Rolf Steinort

Yep, that’s right. I’ve managed to talk Rolf Steinort of Meet the GIMP fame into helping me out with the site. We’re still not 100% sure exactly what this means yet, but I have already been bouncing ideas off him for some of the site details anyway.

Meet the GIMP is over 7 years old now, and quickly closing in on episode 200! I am excited (and honored) to have his expertise and help as we build this site out. Especially because my feeble attempts at video productions are sad at best, and Rolf has the type of voice that could read the phone book and I’d still listen to it.

Content Status

I’m currently in the process of choosing which articles from my archive on Getting Around in GIMP I want to translate over and possibly update/rewrite. If anyone has suggestions on which ones they’d like to see, you can always let me know.

I’m currently thinking possibly the big B&W Conversion, the 2.5D Parallax, and/or the Film Emulation in GIMP/G’MIC.

Breaking Up Long Pages

One other thing that I’m trying to decide on is if I should worry about breaking up long posts into multiple pages or not. I don’t really have any interest in making users click through multiple pages to get all of the content (I personally hate doing this).

On the other hand, if the post is really long it could take some time to load all the assets if they all exist on a single page. It may be a delicate trade-off for keeping a page responsive vs. requiring a user to click through to a second (or possibly third) page. For the moment I’m erring on the side of convenience for the user and keeping things as long pages.

The Big Picture

This is all about visual media after all...

Sometimes I get into weird OCD mode where I need to have something for better or worse. One of those things was a desire to break out of the mold of standard blog-type posts in articles for this site. I’ve sometimes found images are relegated to second-class citizens on some page layouts that don’t do them justice.

I couldn’t let that happen here. The problem was that I needed to do some things to make sure the typographic layouts were visually strong as well. This meant a adding control to width and layout of main text elements, with the downside of having to hack a bit to make images large. The solution I ended up with was to add a tag surrounding elements that I wanted to break out of the current layout. So I would end up with something like this:

<!-- FULL-WIDTH -->
<img src="http://to be full width.png"/>
<!-- /FULL-WIDTH -->

Technically, in my case, I’m using the <figure> tag with <figcaption>, so my actual markup for full-width images looks like this:

<!-- FULL-WIDTH -->
<figure>
<img src="http://full-width-image-src.jpg" />
<figcaption>A caption for my image</figcaption>
</figure>
<!-- /FULL-WIDTH -->

This let me capture that block in my processing when I build the site (metalsmith), and to modify the page code to accommodate what’s needed to make it full-width. The result of this is that I can now break images out of their containers to span the full width of a page, like this:

Of course, this can get very tiring very quickly. I find that it tends to break the flow of reading, so should be used sparingly and wisely in the context of the post or article. I promise not to abuse it.

Attribution

It’s a small thing, but I’ve added an attribution line for the lede images that you’ll find in the bottom right of the actual image. I will also be incorporating the Creative Commons icon fonts to support proper attribution notice as well. Once I’ve done that, I will include a similar style attribution for other images (as it stands now, they can be put into the <figure> image caption).

Video Killed the Radio Star

Of course, sometimes what is needed to really explain a concept is to use a video. So I couldn’t just ignore a way to get good video styling.

My first hurdle was to find a way to keep the video container fluid with the rest of the page. Remember, the page is built to be responsive, so it’s a single page served to all devices. This means that I need to adapt to all possible viewing device screen resolutions (as well as possible).

Getting images to scale and resize correctly to fit new sizes was easy. Doing the same thing for video is not as easy, but wasn’t too bad. Once again, I’m relying on the kindness of strangers…

The Code

The answer came in the form of an A List Apart article from 2009 by Thierry Koblentz. The basic premise was to create a box to contain the video embed, then to stretch the video to fill the box dimensions. Then I could still the box to be responsive just like the other elements.

So I wrapped the video embed in a container box, and added some CSS classes:

<div class="fluid-video">
  <iframe src="http://Normal Youtube Embed Code"/>
</div>

Then it was just a matter of styling by setting the padding property to be percentage based on th width of the container. To use a 16:9 ratio, the percentage should be 56.25%:

.fluid-video {
    position: relative;
    padding-bottom: 56.25%;
    padding-top: 30px;
    height: 0;
    overflow: hidden;
}

With the container styled, it was a simple matter to fill the container with the embedded video:

.fluid-video iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

Et voila! Fluid video embeds that hopefully should maintain responsiveness.

Of course, I couldn’t leave well enough alone, and to coincide with the previous idea of displaying larger images, I have also added a little extra to embiggen video embeds as well (not full width stretching, but to give it a bit more prominence).

Technically I’m stretching the video to 150% of the width of it’s parent container, which happens to be the same container as the <p> elements (so roughly 150% of the text column width). Mostly I was going to use this type of styling for highlight videos, and leave a normal video embed if it’s not the focus of the article.

Just for reference, a normal (fluid) embed would look like this relative to the surrounding text:

Which makes more sense for supporting material vs. feature videos.

Wrap it up Already

Ok, I could ramble on for longer, but I think my time is better spent getting back to writing the site. I think the blog back-end and formatting is mostly done at this point, so on to feature articles!

RSS Feed & Social Media

Finally getting the RSS feed working

It took a bit of digging and wrestling to get there, but a couple of nights ago I also managed to get an RSS feed working for the blog posts on the site. Honestly, I spent more time fiddling with dates in javascript than I should have.

I had to make some minor modifications this morning to accommodate where the location should be, but it should be live now.

The location is: http://pixls.us/blog/feed.xml.

Both the blog index pages and post pages contain a <link> element that point to it, so most readers should find the feed if you point it at a page. I’ll test it later, but the most important thing is the location is correct regardless of whatever hacking I do to the feed itself later.

I’ve tested the feed quickly with feedly and it appears to be working ok. If anyone else is using other feed readers and sees a problem, please let me know!

I intend to have a separate feed available for the articles and main site content when I get those ready to go (most likely at http://pixls.us/articles/feed.xml).

Social Media

I’ve also started (perhaps prematurely?) getting some social media accounts registered. If for nothing else than to keep someone else from parking the accounts.

Google+

At the moment, I’ve got a Google+ page setup for the site. I’ll try to keep updates flowing to that page as well (so if you happen to use g+, follow it!). If you already follow me on g+ then you’ll know I’m fairly active there.

Now if I could just get google to allow my vanity URL to only read +pixlus I’d be a happy camper!

Twitter

Back when I first registered this domain name, I apparently had the foresight to register a Twitter handle as well. So if you want to follow the conversation there, you can find me @pixlsus. I even found a first tweet back from Dec 2011!

Flickr

I’ve also created a Flickr group for users on Flickr to share photos or congregate. You can find the group here.

Really this is just a pre-emptive action to have these channels available as soon as we get going.

Moving Along

I feel like I’m gaining a little traction here. There’s a few more things I need to tidy up and make some design decisions on, but at least I have a clear vision going forward. I’ve already got an article ported over from Getting Around in GIMP on my blog to use as a test case for formatting.

As soon as I like how it’s looking, I’ll work on porting over some other articles as well. If it goes well, I may just go ahead and update/re-write some more things as well to test with. As soon as I have things in a relatively stable state I’ll also get some new material out as well!

A Push Menu

A Fanc(y|ier) Menu

So, I’ve had the idea in my head for a while that it would be nice to get the navigation out of the way. When I’m reading an article or tutorial, I don’t want to be inundated with elements that aren’t pertinent to what I’m reading. I want to focus on the content.

I had to think a bit on the best way to possibly achieve this. One option was to remove all navigation from the top of the page, and instead show them at the end of the article. This runs on the assumption that the user wants to read the page, and when they’re finished reading to possibly navigate somewhere else.

If they came to the page by mistake, or want to get out, they can always use “Back” on their browser. If they made it to the end of the article, then that’s the point where they may want other navigation options. (This is how the page is currently laid out).

If they don’t have javascript turned on, they can still use the site just fine. (This is important for accessibility, and security for some folks).

What About a Little More?

This is 2014 for the love of Pete! Surely we can reasonably expect that most users will have javascript? Well, maybe not. If they do, however, we might be able to create something slightly nicer.

I personally like the idea of a menu hidden out of the way until needed. So I put a small floating logo in the top-left of the page. If you scroll down, the logo should slide out of view (not needed). If you scroll up, it should bring the logo back into view (possibly needed).

This has already been here since I started building these pages, but now I’ve added a little more…

Push Menu

By default a click on the floating navigation logo will scroll the page to the navigation links on the bottom of the page. If JS is turned off, the floating logo will always be visible, and when clicked will still get you to the navigation links quickly.

If JS is turned on, though, the floating logo will now “push” the page to the side as it reveals a navigation menu on the left edge of the page. The first set of links mirror those at the end of the page for site navigation. The next set of links is a representation of the “Table of Contents” for the current page.

This is anticipation of longer articles being posted soon. I wanted to have an easier means of navigating long posts.

Try it out!

Clicking anywhere on the main page again will collapse the menu.

Pure CSS Solution

There may actually be a pure CSS solution for hiding/showing the menu. The javascript is really only there to manage class states, all of the styling and transition effects are done in CSS.

Honestly, though, I think I’m mostly done for the moment. I may come back and re-visit the pure CSS solution later, but for now I want to shift focus to working on content pages (and the actual content itself!).

Start Simple

My thought process so far on building the site is to minimize any requirements on stuff that’s questionable. I’m only assuming HTML/CSS for the most part. This is to make sure everything can still be accessible to folks.

It’s a royal PITA, though.

A Table of Contents!

So the addition of basic navigational elements was a no brainer, but that menu bar looked awfully sparse. So, I used the extra space to include a “Table of Contents” for the current post/article as well. This is generated automatically from all of the HTML heading tags in the page (h1/2/3/4/5).

My intention at the moment is to also have some sort of a reading progress indicator show up along the TOC. I think this could provide nice visual feedback to users on where they are in an article, and how far along they might be.

Again, this is something that should degrade just fine in older browsers/no-js. Those users simply won’t see the effect.

On Building PIXLS.US

Some notes from the back end

For the curious, and to serve as an introduction, I thought I’d make a few notes about how this site is built and what I’m currently obsessing over. Hopefully this can help define what I’m up to in case anyone wants to jump in and help out.

The Purpose

The entire point of this site, its “mission statement” if you will, is:

To provide tutorials, workflows and a showcase for high-quality photography using Free/Open Source Software.

Subject to revisions, of course, but mostly sums up what I’d like to accomplish here. I also think it’s good to have this documented somewhere to remind me. :)

The Technical

I had already started writing about this elsewhere, but I’m going to reiterate it here for posterity (when I wrote it earlier I hadn’t completed the blog portion of the site yet).

Static Pages

On the recommendation of darix on the #darktable irc channel, I looked into static site generators. I was originally going to use some sort of CMS and build things out from there, but I have to thank darix for causing me to pause and to think carefully about how to proceed.

I realized that I wanted to keep things simple. The main focus of the site is the articles themselves (a tutorial, workflow, or showcase). Really, this content is static by nature - so it made sense to approach it in that light.

The idea is to have all of the site content exist locally on my machine, then to pass it through some sort of processor to output all of the website pages ready to upload to my server. I was already familiar with the process as the GIMP website is built in a similar fashion.

I just had to find a static site generator that I could use and extend as needed.

Enter Metalsmith

There is a plethora of static site generators out there (apparently it’s the hip new thing?), so I just had to find one that I was comfortable with using and extending. I needed it to do what I wanted and get the hell out of the way so I could focus on content.

Oh, and I had to be able to extend it as needed myself. I’m already pretty comfortable writing for the web, so I decided to go with the Node.js-based Metalsmith. Mostly because I’m already comfortable making a mess in javascript.

Metalsmith basically takes a directory full of data, and passes those objects through any series of functions I want, munges them somehow, and then spits out my website. It’s the munging part that’s fun, and at least I can extend/modify things as needed quickly and easily.

tl;dr: I use javascript to process the files and output the website ready to upload.

Responsiveness

I also wanted the site to work well across different screen sizes and devices. So I’m trying to incorporate some responsiveness in the design. You can actually see it working right now by resizing your browser width. The page should reflow and elements change size to adapt to the new viewport.

This lets me focus on the content while knowing that it should adapt as needed to the viewer. As a great starting point, I used Adam Kaplans Grid.

Easy Reading

Taking a cue from the past, I’m also trying to maintain legibility and readability in the pages. This means paying attention to simple things like characters per line, font choices, and spacing. I’m not a designer, so this topic has been fun to learn about as I go.

The lines on this post, for instance, should settle in around 60-75 characters per line (I’m aiming for about 65). The Baymard Institute has a nice summary of the idea behind this.

Attractive

This goes without saying, I think, but who wants to look at an ugly layout/site? I can’t say this site is beautiful, but at least I’m conciously trying to make it a pleasant experience…

If not for everyone, at least for me…

Ease of Use

All the pretty in the world won’t fix something that’s hard to use. So I’m trying to put thought into user interaction. I try to get cruft out of the way so the focus is on the articles, while also providing easy navigation or interaction (that should get the hell out of the way when it’s not needed).

In Summary

That’s the short version. There’s a million things going on right now in my head as I build the site out. I’ve got most of the pieces sorted out, and just need to finish assembling them in a way that I like.

So we should be ready to get things kicked off before too long!

Hello World!

Let's see if I can get this thing off the ground...

Well, technically this isn’t the first post on the site. I had actually started with building out the temporary Coming Soon page. Then I shifted focus on styling the main content page for the site (articles). After a bit I realized that I should probably be working on some sort of blog posts as a means for folks to keep up with what I’m doing.

So, here we are!

Who Am I?

I’m Pat David.

I’m an occasional photographer and I dabble in digital artwork occasionally as the mood strikes me. I also happen to be a fan of free software. Those two worlds collide fairly often, and lately I’ve been having a great time writing about them.

I’ve been writing tutorials on my blog as well as trying to modernize/update tutorials on the GIMP website. You could call me a (small) part of the GIMP team (but I’m trying to do more!). I also try to help out where I can on other F/OSS projects as well (G’MIC is another place you’ll find me bumming around). I do these things because I think it’s important to try and give back to the community in whatever way you’re capable of.

I’m loud. So I figured I could use that capability to help out.

(It’s my demented super-power).

So What’s Going on Here?

Well, I mentioned on the main page that I felt like we could use a site/community dedicated to photography. Particularly Free/Open Source Software and photography.

The problem I noticed is a lack of sites that focus explicitly on photography and workflows using F/OSS tools. There are plenty of blog posts on various sites, forum posts on various boards, and the occasional group on social media. There is not a great website to act as a portal specifically for photographic needs or interests.

It’s my sincere desire that I can build it.

I actually find it strange to write that. How does this not exist already?!

Is It Ready Yet?

No. Not quite.

I’m building this entire site from scratch, so it’s taking a little bit of time. I only just got the blog portion finished, so hopefully that much is done.

I’ve also mostly finished what the main articles will look like. I’m in the process of porting over some of my tutorials from my blog to here so that I can have some content to test things out with. I enjoy doing this sort of thing, so it’s a nice way to relax for me.

After that I’ll just need to get a couple of other pages setup, and I should at least have the skeleton of the site up and running. I promise, as soon as I have something to actually launch I will be loud and annoying about it.

Can I Help?

That’s the spirit!

Yes, absolutely. Just shoot me an email and I’ll be happy to answer any questions I can. If there’s some particular skill you’d like to bring, I’m all ears. If you want to write an article or tutorial, let me know.