The *saturation* of a color is the distance of that color from a
gray of equal intensity.[30] Haeberli has suggested
modifying saturation using the equation:

where:

with , , and as described in the above section. Since the saturation of a color is the difference between the color and a gray value of equal intensity, it is comforting to note that setting to gives the luminance equation. Setting to leaves the saturation unchanged; setting it to takes the complement of the colors [42].

2001-01-10