Value
How light or dark a colour is, on a scale from black to white.
Also: tonal value
Value is the painter's word for lightness. Every colour has a value: yellow is naturally light, violet naturally dark. One way to see value is to squint, or to turn a photograph to black and white. Artists often say that value does the work and colour gets the credit, because a picture with a clear pattern of lights and darks reads well whatever hues are used. In the Munsell system value runs from 0 for black to 10 for white. Text is easy to read only when its value differs enough from the background.