Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!pyramid!voder!apple!grady
From: grady@Apple.COM (Grady Ward)
Newsgroups: comp.graphics
Subject: Re: Naive Question About Primary Colors
Message-ID: <7779@apple.Apple.Com>
Date: 25 Mar 88 17:27:31 GMT
References: <7871@oberon.USC.EDU>
Reply-To: grady@apple.UUCP (Grady Ward)
Distribution: na
Organization: Apple Computer Inc, Cupertino, CA
Lines: 14
Keywords: Yellow versus Green


  The question is not so naive.  While frequency of light is a continuum, the
eye believe there are primary colors because of its own physiology, not because
colors exist external to it.  Any set of three colors can be "primary" for non-
color blind humans, beacuse, like a TV set, we have three sensing rod varieties.

The colors red, blue, green are only one example of primaries (ones which
require the least addition of white to make all the rest of the colors).  Paint pigments combine in a subtractive way, though, and red blue yellow are usually
chosen by people using pigments (paints) rather than light becasue they, too,
require the least addition of white to make all the rest of the non-primary
colors.

A succinct primer on color physiology is to be found in Feynmann's work in beginning physics (1962).
Grady Ward