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A Colour Theory Diagram

Glossary of Terms

A Guide to Colour Theory


This is what we usually mean when we ask "what color is that?" The property of color that we are actually asking about is "hue". For example, when we talk about colors that are red, yellow, green, and blue, we are talking about hue. Different hues are caused by different wavelengths of light. Therefore, this aspect of color is usually easy to recognize.

Contrast of Hue - Different hues

Hue Constant - Different Colors, same Hue (Blue)



Think about a color's "purity" when describing its "chromaticity" or "CHROMA". This property of color tells us how pure a hue is. That means there is no white, black, or gray present in a color that has high chroma. These colors will appear very vivid. This concept is related to and often confused with saturation. (see below)

High Chroma - very shiny, vivid

Low Chroma - achromatic, no hue

Constant Chroma - medium chroma

Less purity than top example.



Related to chromaticity, saturation tells us how a color looks under certain lighting conditions. For instance, a room painted a solid color will appear different at night than in daylight. Over the course of the day, although the color is the same, the saturation changes. This property of color can also be called intensity. Be careful not to think about SATURATION in terms of light and dark but rather in terms of pale or weak and pure or strong.

Saturation Constant - same intensity, different hues

Saturation Contrast - various intensity, same hue



When we describe a color as "light" or "dark", we are discussing its value or "brightness". This property of color tells us how light or dark a color is based on how close it is to white. For instance, canary yellow would be considered lighter than navy blue which in turn is lighter than black. Therefore, the value of canary yellow is higher than navy blue and black.

Low Constant Value - same brightness level

Contrast of Value - differences in brightness



A certain color can be defined by hue (0° - 360°), saturation (0% - 100%) and lightness (0% - 100%). Luminance on the other hand is a measure to describe the perceived brightness of a color (Encyclopædia Britannica: "luminance, or visually perceived brightness"). You can lighten or darken a color by adjusting its lightness value, but lightness is not the only dimension to consider for luminance. That is because each hue naturally has an individual luminance value.

colour wheel showing luminance percentage

You can see that blue has the lowest and yellow has the highest luminance value. Yellow is actually just six percentage steps away from white. It's good advice to roughly remember the luminance values of the main hues, as it helps to work more intuitively with color.

If luminance is dependent on hue, it's also dependent on saturation. Reducing the saturation level of any pure hue to 0% results in a 50%-gray and a 50% value in luminance respectively. So for hues with natural luminance above 50%, luminance decreases when the saturation level decreases. For hues with natural luminance below 50%, luminance increases when the saturation level decreases.


Tints, Tones and Shades

These expressions are often used inappropriately but they describe fairly simple color concepts. The important thing to remember is how the color varies from its original hue. If white is added to a color, the lighter version is called a "tint". If the color is made darker by adding black, the result is called a "shade". And if gray is added, each gradation gives you a different "tone."

Tints (adding white to a pure hue)

Shades (adding black to a pure hue)

Tones (adding gray to a pure hue)


Complementary Colors

When two or more colors "go together," they are said to be "complementary." This is completely subjective and open to interpretation and differences in opinion. A more exact definition is "any two colors that, when mixed together produce a neutral gray (paints/pigments) or white (light).

Primary Colors

This definition really depends on what type of medium of color we are using. The colors that are seen when sunlight is split by a prism are sometimes called the spectral colors. These are red, orange, yellow, green, blue, indigo, and violet. These ROYGBIV colors are often reduced to three "red, green, and blue-violet" which are the primary colors for the additive color system (light). The primary colors for the subtractive color system (paint/pigment) are cyan, magenta and yellow.


Secondary Colors



Tertiary Colors



Split Complimentary Colors



Analogous Colors






Square Colors



Tetradic Colors




Different color systems are used for different color conditions depending on how the color is created. When using projected light, RGB or red/green/blue, is the governing system. For color that is mixed with paints, pigments or inks on fabric, paper, canvas or some other material, CMY or cyan/magenta/yellow, is the color model. Because these pure pigments tend to be quite expensive, Black, symbolized by "K", is substituted for equal parts of CMY to lower costs of ink. Another major color system is HSL or hue/satuation/lightness. This system has many variants switching saturation with chroma, luminance with value etc. but is usually consistent with how the human eye sees color.