There are two basic ways colors can be mixed to make other colors. One way is by combining color illumination or light. The other way is by mixing together media such as paint, inks, dyes, and other colorants. This is called "subtractive" color mixing.
Subtractive mixing takes place whenever any two or more colors of paint, marker, ink, or dye are mixed together
Subtractive mixing is also used when one or more transparent color media are applied one over the other.