How to create HaldCLUT from difference between two images

[David_Tschumperle (G'MIC staff)]

@Morgan_Hardwood

times one would like to be able to create a HaldCLUT of processing done by some hardware or software which does not permit you to pass through it a HaldCLUT identity image. One solution would be to photograph the identity image (or some color target with patches), process that raw photo in said hardware/software and save as a separate file, and then use the before/after non-raw images to create the HaldCLUT.

Filter CLUT from After/Before Layers is not enough ?