RGB (reg, green, blue) modes|
These modes are different to the modes above, because not the same formula is applied to all color channels.
A single color channel is extracted from the blend image, the other color channels are taken from the base image.
Formula (for red):
fred(a,b) = bred
fgreen(a,b) = agreen
fblue(a,b) = ablue
For green and blue mode simply permutate the formula above.
You can also create cyan, magenta and yellow modes if you assign b to two channels and a to one channel only.
Code (for red):