To successfully mix the colors you’ve interpreted certainly requires experience but follows this fairly simple logic originating with the local (say Red), recognizing the form type (say a sphere), the light most facing plane (therefore, the lightest in value and chroma) and the visibility of these properties as less light is received (therefore darker in value and less chromatic). This translates to mixing up a Red on your palette (an optical match to the Red in life can be attempted or, should you choose, be transposed to an alternative tone provided it subsequently follows a physical logic).
From there, you search about on your palette for other pigments that will diminish the value and the chroma while keeping the hue stable. For example, if you began adding only Ivory Black to your Red, you will certainly be diminishing both chroma and the value, but you’ll also be pulling the Red off of a radius to the neutral, thus shifting it towards a low chroma Violet. You then think directionally in color space and ask what might take you back towards center Red while maintaining the downward path of value and chroma. You could try Raw Umber and in a particular situation, that might be enough. If not, other colors are called upon (this should indicate the primacy of concepts over learned mixture patterns). It is the understanding of what’s physically happening that keep us out of the wilderness of bizarre coloration. It also let’s us follow a logic that is relational and not necessarily dependent on the optical. I find this very liberating artistically.
- Scott’s Sketchbook