I am using my Kroma Kolor black for airbrushing and it is turning a deep green. Does anyone have a quick solution for turning it to a true black?
Add a little purple (or some red and some blue if you don't have purple.) It may not get you true black. But it'll get you close to it.
Is you cake cold and sweating, or is it very humid where you are? That will cause the black to bleed to it's base color.
I agree that you should add some purple to it to try and balance the spectrum out.