Secondary color

A secondary color is a color made by mixing two primary colors in a given color space. Examples include the following:

Pigment (CMY)
This is often referred to as CMYK where K stands for Key (usually black). In theory, solid overlapping layers of C, M, and Y ink produce black. In reality the outcome is dirty brown unless mixed exactly evenly so the black ink replaces the other three layers. See under color removal.

Traditional painting (RYB)
RYB uses pigments, similar to CMY, which combine subtractively by absorbing light. Thus, combining colors using the RYB color system will result in a darker color.