Color theory encompasses a multitude of definitions, concepts and design applications. All the information would fill several encyclopedias. As an introduction, here are a few basic concepts.

The Color Wheel

12 part color wheel

A color circle, based on red, yellow and blue, is traditional in the field of art. Sir Isaac Newton developed the first circular diagram of colors in 1666. Since then scientists and artists have studied and designed numerous variations of this concept. Differences of opinion about the validity of one format over another continue to provoke debate. In reality, any color circle or color wheel which presents a logically arranged sequence of pure hues has merit.

Primary colors

Red, yellow and blue

In traditional color theory, these are the 3 pigment colors that can not be mixed or formed by any combination of other colors. All other colors are derived from these 3 hues

Green, orange and purple

These are the colors formed by mixing the primary colors.

Yellow-orange, red-orange, red-purple, blue-purple, blue-green and yellow-green.

These are the colors formed by mixing a primary and a secondary color. That’s why the hue is a two word name, such as blue-green, red-violet, and yellow-orange.


Harmony can be defined as a pleasing arrangement of parts, whether it be music, poetry, color, or even an ice cream sundae.

In visual experiences, harmony is something that is pleasing to the eye. It engages the viewer and it creates an inner sense of order, a balance in the visual experience. When something is not harmonious, it’s either boring or chaotic. At one extreme is a visual experience that is so bland that the viewer is not engaged. The human brain will reject under-stimulating information. At the other extreme is a visual experience that is so overdone, so chaotic that the viewer can’t stand to look at it. The human brain rejects what it can not organize, what it can not understand. The visual task requires that we present a logical structure. Color harmony delivers visual interest and a sense of order.

In summary, extreme unity leads to under-stimulation, extreme complexity leads to over-stimulation. Harmony is a dynamic equilibrium.

Some Formulas for Color Harmony 

There are many theories for harmony. The following illustrations and descriptions present some basic formulas .

A color scheme based on analogous colors

Example of an anaologous color harmony

Analogous colors are any three colors which are side by side on a 12 part color wheel, such as yellow-green, yellow, and yellow-orange. Usually one of the three colors predominates.

A color scheme based on complementary colors 

Example of a complementary color harmony

Complementary colors are any two colors which are directly opposite each other, such as red and green and red-purple and yellow-green. In the illustration above, there are several variations of yellow-green in the leaves and several variations of red-purple in the orchid. These opposing colors create maximum contrast and maximum stability.

A color scheme based on nature

color harmony in nature

Nature provides a perfect departure point for color harmony. In the illustration above, red yellow and green create a harmonious design, regardless of whether this combination fits into a technical formula for color harmony.

Color Context

How color behaves in relation to other colors and shapes is a complex area of color theory. Compare the contrast effects of different color backgrounds for the same red square.

©Color Voodoo Publications

Red appears more brilliant against a black background and somewhat duller against the white background. In contrast with orange, the red appears lifeless; in contrast with blue-green, it exhibits brilliance. Notice that the red square appears larger on black than on other background colors.

Different readings of the same color

©Color Voodoo Publications

If your computer has sufficient color stability and gamma correction (link to Color Blind Computers) you will see that the small purple rectangle on the left appears to have a red-purple tinge when compared to the small purple rectangle on the right. They are both the same color as seen in the illustration below. This demonstrates how three colors can be perceived as four colors.

Observing the effects colors have on each other is the starting point for understanding the relativity of color. The relationship of values, saturations and the warmth or coolness of respective hues can cause noticeable differences in our perception of color. 

some Illustrations and text, courtesy of
Color Logic
and Color Logic for Web Site Design


Additive and Subtractive Color

There are two basic color models: Additive Color and Subtractive Color.

Additive Color involves the mixing of colored light. The colors on a television screen are a good example of this. Additive primary colors are red, green and blue.

Subtractive Color involves the mixing of colored paints, pigments, inks and dyes. The traditional subtractive primary colors are red, yellow and blue.

In this lesson we are examining the terms used to describe Subtractive Color.


the spectrum

The spectrum is the colors of the rainbow arranged in their natural order: Red – Orange – Yellow – Green – Blue – Indigo – Violet. The mnemonic for this is ROY G BIV.


the color wheel

The Color Wheel

Click here for an A4 outline of the color wheel to print and colour.

A hue is one of the colors of the spectrum. Hues have a circular order as illustrated in the color wheel above. The color wheel is a useful device to help us explain the relationships between Primary, Secondary and Tertiary colors.


primary colors

Red, Yellow and Blue are the primary colors. These are the three basic colors that are used to mix all hues.


secondary colors

Orange, Green and Purple are the secondary colors. They are achieved by mixing two primary colors together.


tertiary colors

Tertiary colors are more subtle hues which are achieved by mixing a primary and a secondary color that are adjacent on the color wheel.


opposite colors

Opposite colors are diagonally opposite one another on the color wheel. Opposite colors create the maximum contrast with one another. You can work out the opposite color to any primary color by taking the other two primaries and mixing them together. The result will be its opposite or ‘complementary’ color.


analogous colors

Analogous colors sit next to one another on the color wheel. These colors are in harmony with one another.