A curated list of free-libre-opensource image processing software, ideal for photographers :)

Image processing can be performed using Darktable, as a FLOSS alternative to Adobe Lightroom.

Another interesting alternative is RawTherapee.

Image can be manipulated (also processed) using GIMP as an alternative to Adobe Photoshop.

Some interesting plugins:

• gimp-plugin-astronomy
• gimp-plugin-beautify
• gimp-plugin-bimp
• gimp-plugin-dcamnoise2
• gimp-plugin-pandora
• gimp-plugin-reflection
• gimp-plugin-resynthesizer
• gimp-plugin-refocusit
• gimp-plugin-saveforweb
• gimp-plugin-separate+
• gimp-plugin-wavelet-sharpen

The idea is to achieve one unique image that stacks a set of the same picture over different exposures.

In this example we're going to stack 16 RAW files (of course you can use your processed files instead of the raw ones):

convert DSC0133[7-9].ARW DSC0134* DSC0135[0-3].ARW -evaluate-sequence median stack_bracket_16.tif

, this will provide the stacked image stack_bracket_16.tiff averaging the requested source images.

Panos can be created using hugin.

Just start it, load source files and start "composing".

Of course, the same tool can be used for Vertoramas.

There are some options, but one of the simplest flows is to chain ffmpeg and mencoder.

In this example we'll use our processed TIFF files to create an animation, and

ffmpeg -r 24 -pattern_type glob -i '*.tif'  -s hd1080 -vcodec libx264 timelapse.mp4

mencoder -speed 0.5 -ofps 24 -ovc copy timelapse.mp4 timelapse_slow.mp4

, those parameters can be adapted to your needs, in this case we're

• 1. creating the timelapse.mp4 video at 24fps
• 2. reducing the speed of the final video to increase the length and provide smoother transitions in timelapse_slow.mp4