why this method works? What’s the point of channel mixer here, and how/why chose the settings?
is it still the way one would make eye pop in 2026 with the new scene-refered workflow/AgX? Is there other alternatives (and their pro/cons) to achieve this goal? I usually just increase exposure + saturation but I’m sure it is not the best solution.
Note the mask, it is crucial. You can use the channel mixer here: in HSV Lightness blend mode, only the V channel (lightness) changes, whatever you do, so if you push up eg the blue channel, it will make whatever is blue lighter.
The video was made with Darktable 3.something if I remember the GUI correctly, recent (4.x?) versions have a “brightness” tab in color calibration to do this directly, in scene-referred workflow. Try it! Leave the standard blend mode. It is for scene-referred.
You choose the settings by eyeballing the result. You choose the channel by noting what color is dominant in whatever you want to change.
Alternatively, cf the color equalizer which can also make some colors brighter. I think that in this image, picking the blueish part is useful because it separates the eye from the surrounding skin.
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