Channel Mixer
An adjustment that builds each output channel from a weighted combination of the red, green and blue input channels.
Formula / rule
Out = aR + bG + cB
Measured in
%
In depth
For monochrome conversion, the mixer determines exactly how much each colour contributes to the grey result, with the weights conventionally summing to 100 per cent to preserve overall brightness. In colour work it can perform strong cross-channel corrections that no hue or saturation control can achieve.
Examples in practice
A monochrome mix of 60 per cent red, 30 green and 10 blue lightens skin and darkens sky in one operation.