Color theory is the study of how colors mix with each other to create other colors.
There are three primary colors, red, blue and yellow. They are called primary because these pigments cannot be created from other colors.
The secondary colors are green, orange and purple. These colors are created by mixing the primary colors. Yellow and blue make green, red and yellow make orange, and blue and red make purple.
Colors are altered by the addition of black or white. In color theory terms, if you add black you shade the color, if you add white, you tint the color.
The color wheel is a graphic representation of the relationships among colors.
Sir Isaac Newton presented the first color wheel in 1666.