Re: [Groff] CMYK <-> RGB

[Ralph Corderoy]

Hi Werner,

> Which one is the `best' or the `correct' one?

To answer a separate question :-) Foley, van Dam, et al's _Computer
Graphics, Principles and Practice_ says that CMY shares the same
Cartesian coordinate space as RGB and since they're the complement of
each other converting from CMY to RGB is straightforward.

    R   1   C
    G = 1 - M
    B   1   Y

Turning CMY into CMYK is similarly simple.

    K = min(C, M, Y)
    C = C - K
    M = M - K
    Y = Y - K

Hope this is of some help.


Ralph.