The adjust saturation can't be used for a one color PF. That's the problem if you need only one color to be variably desaturated. Black is automatically added. So an alternative route has to be found when needing to subdue colors, and the only way I found is to add a double color PF before the single color. I'll be looking for another solution, but has anyone encountered and solved this?
Does this fit your needs?
SaturationMask.JPG
SaturationMask..tgd
Smart solution! Thanks, Richard!