Complementary Colors

In addition to the term Primary and Secondary colors, another term has been used to describe colors that when combined, create neutral colors: "Complementary Colors". In color theory, two colors are called complementary if when mixed, they produce one of the neutral colors: gray, white or black.

While the term complementary colors can refer to different sets of colors depending on the color model (i.e. Additive - RGB, versus Subtractive - CMYK), for our purposes we will describe complementary colors based on their usage in art and design. The following color combinations are considered complementary colors:

Red - Green
Blue - Orange
Yellow - Violet

Within the subtractive system (CMYK), these complementary colors are similar to the colors created through the mixing of the two primary colors:

Red complements (blue + yellow) = Green
Blue complements (red + yellow) = Orange
Yellow complements (red + blue) = Violet

The BYR color wheel (see below) is a helpful visual of complementary colors as used in art and design. Colors opposite of each other are considered complementary.

In dentistry, complementary colors play a significant role in porcelain staining. For example, if a restoration is seen as too orange, adding shades of blue will create a more grayish color.

Portions of this post were adapted from the book:
Fundaments of Color - Shade Matching and Communication in Esthetic Dentistry published by Quintessence Publishing Co. Inc and written by Dr. Stephen J. Chu, Dr. Alessandro Devigus, Dr. Rade D. Paravina and Mr. Adam J. Mieleszko. and the
Wikipedia articles:
http://en.wikipedia.org/wiki/File:BYR_color_wheel.svg
http://en.wikipedia.org/wiki/Complementary_colors