This color model is defined in the double-cone subset of a cylindrical space. Hue (H) is measured by the angle around the vertical axis, with red at 0 degree, green at 120 degree and so on. The height of the cone represents lightness (L) in a range from 0 (black) at the apex of the first cone to 1.0 (white) at the apex of the second one. Saturation (S) is a ratio ranging from 0 on the center line (V axis) to 1 on the triangular sides of the cones.
a color-coding scheme that specifies a color in terms of its hue, lightness, and saturation components. Hue is the color, lightness is the percentage of white, and saturation is the attribute of a color that determines its relative strength and its departure from gray. Lightness and saturation added to the hue produce a specific shade. See also CMYK, HSV, and RGB.