Complementary

Complementary colors are pairs of colors which cancel each other out when combined and produce a grayscale color like white or black. The greatest contrast available to a given color is its complementary color. Complementary colors may also be called “opposite colors”. Which pairs of colors are considered complementary depends on the color model. For example, the Complementary Color of Red is Cyan in the RGB Color Model and Green in the RYB (traditional) Color Model.

In RGB, a Secondary Color is always the Complement of a Primary Color.