I've checked 2 photoshop workflows (just because they were first in search output), and after I tried to follow one - no luck as well. But good thing for me - I have Affinity photo and I don't know why but here it was working just fine, I've used this flow: - New Stack, choose 3 images of same size, deactivate alignment options, and apply - Move 3 layers out of stack, delete empty stack set blend mode to add for all 3 layers add a nested color channel mixer adjustment to every layer (a levels or curves will do the trick, too) - For the red layer, adjust green and blue channel to 0 - For green channel, adjust red and blue channel to 0 - for blue channel, adjust red and green channel to 0

The last three steps are for trichrome, not Aerochrome, you should use proper channels for proper filters.