Gives the CMYK (cyan, magenta, yellow, key/black) values of a color.
(1-R-K)/(1-K)) is used to convert sRGB to CMYK.
Magenta, `Yellow — Ranges from 0 to 1, where 1 is fully cyan, magenta, or yellow.
Black— Ranges from 0 (full color) to 1 (completely black).
Keywords: CMYKA, alpha, blue, channel, chroma, color space, green, key, opacity, red, tone, transparent