Color charts, or color wheels, are diagrams of colors placed in the order they are found in rainbows or when white light is filtered through a prism. Color charts can contain primary, secondary or tertiary colors, based on their complexity. Sir Isaac Newton created the first one in 1666.
Red, blue and yellow are the primary colors. These colors mixed in various combinations create all other colors; no other colors can be mixed to create primary colors. The secondary colors are green, orange and purple. They are formed by mixing two adjacent primary colors and sit in between the primary colors on the color wheel.
Tertiary colors are formed by mixing a primary color with a secondary color. Examples are yellow-orange, red-violet and blue-green. They sit in between a primary and a secondary color on the color wheel. Beyond this, the number of colors is virtually unlimited.
Once an artist's tool, color charts are now used in everything from home decorating to auto body work. They are handy in selecting complementary and analogous color schemes. Complementary colors sit across from each other on the color chart. Analogous colors sit next to each other. Colors used for commercial purposes, such as picking out house paint, are usually shown in analogous strip charts.