ColorDistance

Color difference (WMA link)


ColorDistance[$c_1$, $c_2$]

returns a measure of color distance between the colors $c_1$ and $c_2$.

ColorDistance[list, $c_2$]

returns a list of color distances between the colors in list and $c_2$.

The option DistanceFunction specifies the method used to measure the color
distance. Available options are:

It is also possible to specify a custom distance.

CMYKColor
GrayLevel