Hue, Saturation, and Lightness. A method of describing any colour as a triplet of real values. The hue represents the colour or wavelength of the colour. It is sometimes called tone and is what most people think of as colour. The hue is taken from the standard colour wheel and is thus calibrated in degrees about the wheel. Saturation is the depth of the colour. It states how gray the colour is. It is real valued parameter from 0.0 to 1.0 with 0.0 indicating full gray and 1.0 representing pure hue. The lightness is how black or white a colour is. It also ranges from 0.0 to 1.0 but with 0.0 representing black and 1.0 white. A lightness of 0.5 is pure hue.
Hue, Saturation and Lightness. A color model that determines the shading and lightness of a color. Hue corresponds to the pure color; saturation to the amount of white mixed with the hue; and light to the brightness of the hue.