Grey - Color Coordinates

Color Coordinates

RGB

Grey values result when r = g = b, for the color (r, g, b)

CMYK

Grey values are produced by c = m = y = 0, for the color (c, m, y, k). Lightness is adjusted by varying k. In theory, any mixture where c = m = y is neutral, but in practice such mixtures are often a muddy brown (see discussion on this topic).

HSL and HSV

Achromatic greys have no hue, so the h code is marked as "undefined" using a dash: -- ; greys also result whenever s is 0 or undefined, as is the case when v is 0 or l is 0 or 1