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RAW Photography and Linux

Funny Fish Heads

As an audio guy, I always heard people talking about RAW photography format, but I didn’t really know much about it. An old co-worker of mine would constantly tell me it was better, but he really couldn’t express it in a meaningful way that made sense to me, so honestly I never really thought much of it.

Recently though I installed a hack on my Canon Powershot that enabled me to shoot in RAW and I wanted to learn more about it. I started reading online and playing with software in Linux and one program quickly came up as what seemed like a great one for RAW photography processing…. Darktable.

So first off, what is RAW? To explain this simply and from an audio engineer’s point of view, imagine your camera lens was a microphone. Now imagine that your camera body is an fx chain that processes what goes into the microphone then converts it to an MP3 before it writes it to memory. Would you want to record sound this way? I wouldn’t. But this is exactly how most cameras record images. You take a picture, the camera lens captures the image and the camera takes color information, exposure compensation, sharpening data, or whatever else gets determined at the time, applies that to the image data, then compresses all of that into a .jpg file which has all of this data permanently stored in the file and unchangeable except for post-processing.

90% of the time, this is just fine for most people. Because the camera was intelligently designed to figure out most of the important work to optimize the image to make it look it’s best according to the settings used at the time the image was captured. But for a serious photographer, or just for anyone who likes having insane amounts of control over all of their creative work, RAW is a much better option. When you shoot in RAW your lens captures the image data, and the camera still captures the processing data, but instead of writing it together into a .jpg file, the image data is stored purely without any processing or compression applied to it and the processing information is stored in a header of the RAW data.

Now back to Darktable.

Darktable is a photo management program for processing RAW images. When you open a RAW file in Darktable, many times you’ll already see a processing history on the image in the left pane of the software. This is because Darktable reads the header information from the RAW file that your camera wrote and applies it to the image data. The major difference here is you can turn it off and see what it looks like without any of that applied. You can decide to use it or not, and you can tweak, add to it, change it, or just discard it all together if you like.

There are many other tools for Linux for working with RAW images. Digikam has RAW processing features, though in my opinion Darktable seems to work much better and is faster. Gimp also has the ability to work with RAW, but not out of the box. You need to install the UFRaw plugin, but once you do, then you have access to a lot of processing tools for RAW images that are quite good. The major difference between this approach instead of using Darktable, is all of the RAW processing is done in the importing process of Gimp. This may be good or bad depending on your needs. Gimp has a more robust set of editing features more similar to Photoshop, where Darktable has a lot of RAW processing features with endless undos and a very nice photo management system.

My conclusion and personal workflow at least at this moment is Darktable as my organizer and main RAW processor, and Gimp for special and more in-depth editing. You could look at it like: Gimp=Photoshop and Darktable=Lightroom.

I hope you found this article helpful and please ask questions if you have any. I will be making some video tutorials on these subjects in the near future as well.