Originally Posted by
IndyHobbies.com
Maybe you were asking how to mix a darker red? If that was your question, here's the answer.
Red is a primary color. So if you just add black, it can get muddy pretty quick. The right thing to do is to use green or blue. It doesn't take much. Just add a drop and shake the bottle to see it's effect. Open the lid to look. The side of the bottle won't show the actual shade.
Whether you use green or blue really depends on what shade of red you start out with and what shade you are trying to get to. Hope that helps.
That is what I was looking for. I have done some experimentation in mixing colors (I make a gumetal sometimes with metallic silver and black) but darkening never turned out the way I expected it. This clears it up. Thanks