Every pigment occupies a specific position on a color wheel. The position is a combination of its hue and chroma.
The chart above shows where many familiar pigments would appear. Earth colors, since they’re low in chroma, appear close to the center in the red and yellow sectors, and black and white sit together at the center.
Since maximum known chroma varies from one color to another, even the some of the strongest tube colors often fall short of the perimeter.
This chart doesn’t include every pigment. But even if it did, there would gaps where pigments are unavailable.
This chart is hand-painted in oil, using dots of pigment over a high-key gradated Yurmby wheel. Note that the wheel is set up according to the way our eyes actually perceive color relationships. The complements are additive, not paint-mixing complements. So ultramarine blue is opposite cadmium yellow, not burnt sienna. The reason I set it up that way is because I want to know how the colors will relate and vibrate on my picture from the perspective of the viewer’s experience. I’m not as worried which paints I need to mix a gray.
This chart was based on data compiled by Bruce MacEvoy, www.handprint.com.