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From: throopw@xyzzy.UUCP (Wayne A. Throop)
Newsgroups: sci.misc
Subject: Re: Color
Message-ID: <435@xyzzy.UUCP>
Date: Tue, 8-Dec-87 13:30:23 EST
Article-I.D.: xyzzy.435
Posted: Tue Dec  8 13:30:23 1987
Date-Received: Sun, 13-Dec-87 12:45:00 EST
References: <8VicPfy00Xo3QHM08t@andrew.cmu.edu>
Organization: Data General, RTP NC.
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> jk3k+@andrew.cmu.edu (Joseph G. Keane)
> Some more information about color perception:  When you add two colors of 
> light, you get something that looks in-between but less pure.

Simply not true, as Joseph's own example of "purple" shows.  Adding red and
violet doesn't give a yellowish-green as you might expect, but purple.
Again, the above claim is simply not true in general.

> So if i show 
> you a mixture of yellow and blue light, it will indeed look green.  Then if 
> show you monochromatic green light, it will look more green.

I take it you haven't actually tried this.  If you mix yellow and blue
*light*, you normally get something very like white.  (This depends
strongly on the exact spectrums (spectra? whatever) and intensity of
"yellow" and "blue" used of course.)

Now, granted, yellow and blue *pigments*, when mixed, normally yield a
green *pigment*, but that's a horse of a... well, it's a different
kettle of fish, anyhow.

--
"Trust me.  I know what I'm doing."
                                        --- Sledge Hammer
-- 
Wayne Throop      !mcnc!rti!xyzzy!throopw