Color Theory

What is Color Theory?

Color theory is a multitude of categories, definitions and concepts.

This tutorial covers the parts that are most useful for web design:

  • Primary, Secondary, and Tertiary Colors
  • Color Wheels (RGB, CMY, RYB)
  • Color Hue, Lightness and Saturation

The Color of Light

Sir Isaac Newton developed the theory that all colors are mixtures of Red, Green, and Blue light.

This resulted in the first known color circle in 1666.

Sir Isaac Newton
Color Wheel

The Color of Paint

In 1766 the scientist Moses Harris created the first color wheel to classify Red, Yellow, and Blue as the primary colors.

Moses Harris worked with paint (Newton worked with light) following a theory (by a French painter) that all colors are mixtures of Red, Yellow, and Blue pigments.

Moses Harris
Color Wheel

Color Systems

In this tutorial we will cover 3 different color systems:

  • The color system used when producing colors by light (RGB)
  • The color system used when printing (CMY)
  • The color system used by artist and painters (RYB)

Printing actually uses a four ink color system.

CMYK: Cyan, Magenta, Yellow, and Key (black).

Primary Colors

Primary colors are the main colors in a given color system.

Primary colors can not be produced by mixing other colors a color system.

The primary colors for light are Red, Green, and Blue:

RGB Red Green Blue

The primary colors for print are Cyan, Magenta, and Yellow:

CMY Cyan Magenta Yellow

The primary colors for paint are Red, Yellow, and Blue:

RYB Red Yellow Blue

Secondary Colors

Secondary colors are made by mixing two primary colors in a color system

There are 3 secondary colors in the color systems described here.

Mixing Light (RGB)

Secondary colors are Yellow, Cyan Magenta.

Red + Green = Yellow
Green + Blue = Cyan
Blue + Red = Magenta

Mixing Ink (CMY)

Secondary colors are Blue, Red, Green.

Cyan + Magenta = Blue
Magenta + Yellow = Red
Yellow + Cyan = Green

Note that mixing the primary colors of CMY produces the primary colors of light (RGB)

Mixing Paint (RYB)

Secondary colors are Orange, Green, Violet.

Red + Yellow = Orange
Yellow + Blue = Green
Blue + Red = Purple

Tertiary Colors

Tertiary colors are made by mixing two secondary colors in a color system.

There are six named tertiary colors in RYB:

  • Red-Orange
  • Yellow-Orange
  • Yellow-Green
  • Blue-Green
  • Blue-Purple
  • Red-Purple