Field guide
Combine pictures in sRGB or linear light?
sRGB numbers are shaped for display and storage, so halfway between two encoded values is not halfway in emitted light. Blend mode matters before the opacity slider does.
01
Normal alpha compositing is physically meaningful in linear light. Performing it directly on sRGB values often makes the overlap darker than the same mixture of light would be.
02
Artistic modes such as screen and overlay were historically defined in encoded values. Recreating a familiar editor look may therefore require sRGB arithmetic even when it is not physical.
03
Check soft gradients and bright saturated edges. Those areas reveal dark seams and colour shifts more readily than midtone photographs with busy texture.
04
Document the working space when matching another program. Two tools can use the same blend-mode name and still differ because one converts before blending and the other does not.