There are two types of color mixing: Additive and Subtractive. In both cases there are three primary colors, three secondary colors (colors made from 2 of the three primary colors in equal amounts), and one tertiary color made from all three primary colors.
Additive mixing of colors generally involves mixing colors of light. In additive mixing of colors there are three primary colors: red, green, and blue. In the absence of color or, when no colors are showing, the result is black. If all three primary colors are showing, the result is white. When red and green combine, the result is yellow. When red and blue combine, the result is magenta. When blue and green combine, the result is cyan. Additive mixing is used in television and computer monitors to produce a wide range of colors using only three primary colors.
In the visual arts, color theory is a body of practical guidance to color mixing and the visual effects of specific color combination. There are also definitions (or categories) of colors based on the color wheel: primary color, secondary color and tertiary color. Although color theory principles first appeared in the writings of Leone Battista Alberti (c.1435) and the notebooks of Leonardo da Vinci (c.1490), a tradition of "colory theory" began in the 18th century, initially within a partisan controversy around Isaac Newton's theory of color (Opticks, 1704) and the nature of so-called primary colors. From there it developed as an independent artistic tradition with only superficial reference to colorimetry and vision science.