darktable is an open source photo post-production tool, ideal for both professional and amateur photographers. With this application installed on your Linux distribution you can work directly on your photos in RAW format, being able to manage and handle a large amount of images at once.
Making life easier for photographers
darktable basically offers the user a virtual dark room where he can reveal his digital negatives and enhance them using the different modules includes, from the most basic ones (cropping, removing flaws, modifying the exposure, etc.) to the most advanced ones (simulating night vision, among others.).
A serious alternative to LightZone and RawTherapee.
One of the noteworthy aspects of this tool, that unfortunately is still not available for Windows, is that the processing of RAW images is carried out in a non-destructive manner, therefore, the changes applied aren't permanent until the final result is exported, being able to reverse the modifications whenever you want.