I have seen the new feature in g’mic 2.3.4 Add filter Colors / CLUT from after-before layers *. This filter is able to recover the color transformation that has been applied between a pair of images, as a HaldCLUT. This HaldCLUT can then be applied afterwards to a bunch of other images.
Maybe it could be useful. I’ll need to create e.g. with gimp a syntetic grid of colors, and fill it with with colors taken from the images, then try what happens with this g’mic filter.
Unfortunatly the weather here isn’t that great.