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From: piety@hplred.HP.COM (Bob Piety)
Newsgroups: comp.graphics
Subject: Re: RGB ---> YMCK
Message-ID: <260002@hplred.HP.COM>
Date: 8 Feb 90 16:22:00 GMT
References: <1990Feb7.220805.27260@allgfx.agi.oz>
Organization: Hewlett Packard Labs, Palo Alto CA
Lines: 6

Given components in the 0..1 range,

C = 1 - R
M = 1 - G
Y = 1 - B
K = .59R + .30G + .11B = Luminance