The color wheel is a visual representation of color theory, first proposed by Sir Isaac Newton in the 18th century. More a color chart or color scale than anything else, a color wheel shows the relationship colors have to one another.
A color wheel is useful for identifying harmonious colors for a particular context.
The most common version of a color wheel contains 12 colors based on the red yellow blue (RYB) artistic color model. In this model, the primary colors of red, yellow and blue are placed opposite their complementary secondary colors (green, orange and purple) and next to their tertiary color variations (yellow-orange, red-orange, red-purple, blue-purple, blue-green and yellow-green).
Tertiary colors are the colors formed by mixing a primary and secondary color.
Many variations of the traditional RYB color wheel concept exist. Another popular color wheel is the red green blue (RGB) or red green violet (RGV) wheel with the colors cyan, magenta, and yellow as secondary.