Hi, testing the multiply layer. With underlying color 10% (ie value) red (50% saturation) I get:

multiply with:
100% black (0% saturation) -> results in: 100% black (0% saturation)
100% black (100% saturation) -> same: 100% black (0% saturation)
80% black (50% saturation) -> ca 80% black, over 90% saturated

This does not make sense to me.

Here's how multiply works theoretically: https://en.wikipedia.org/wiki/Blend_modes#Multiply .

Also check our manual: https://docs.krita.org/Blending_Modes#Multiply and https://docs.krita.org/Flat_Coloring#Th ... nding_Mode