Unified Theory of Color

The way that pigments mix (subtractive color mixing) to produce colors is different from the way that colored lights mix (additive color mixing). The connections between these two systems are elegant if you use cyan, magenta, and yellow as pigment primaries instead of red, yellow, and blue. 

Cyan, magenta, and yellow are the true primary colors for pigment (see blog Reinventing the Wheel: Why Red is not a primary color). These combine to make darker secondary colors red, green and blue, resulting in black when all three pigments are combined. Lights work the opposite way. Red, green and blue are the primary colors for light. When two colored lights overlap, they produce lighter secondary colors, cyan, yellow or magenta. When all three are combined, they make white light. What is exciting here is that pigments and light share the same color wheel- it is only that the primary and secondary colors are reversed.

comparison of CYM and RGB color wheels

If you are using the traditional pigment primaries, red, yellow and blue, the relationship between additive and subtractive color wheels is confusing. Why would they share red and blue as primary colors but not the have one primary that is different (green or yellow)?