What is Color?

How is color defined?

Three values are used to define a color: First is the hue, sometimes called shade, second is the chroma and the third is the lightness. Every color can be described using these three values and taking the type of light into consideration. This is the basis of colorimetry.

Different shades of color are arranged in a hue circle running clockwise from yellow through orange, red, violet, blue, bluish green and green back to yellow again. A color shade may be lighter or darker depending on its lightness. If the chroma of a color is reduced, then this color will be less brilliant (closer to gray). If the saturation is zero then we talk of an achromatic color. Black, white and all of the intermediate shades of gray are achromatic colors, determined by their lightness.