GIMP washed out colors: Color to Alpha and layer recombination
Just to remind myself because I keep forgetting it again and again: If you get washed out colors when doing color to alpha and then recombine layers in GIMP, that is due to the new default in GIMP 2.10 that combines layers in linear RGB.
This creates problems because Color to Alpha works in perceptual RGB, and the recombination in linear creates washed out colors. The solution is to right click on the respective layer, select “Composite Space”, and there select “RGB (perceptual)”. Here is the “bug” report that has been open since 2 years.
Hoping that for next time I remember it.