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From: hjortsho@cg-atla.UUCP (Erik Hjortshoj)
Newsgroups: sci.electronics,rec.audio
Subject: Re: Looking for Blue LEDs
Keywords: blue blue blue, not yellow or red or green
Message-ID: <5872@cg-atla.UUCP>
Date: 23 Sep 88 13:20:00 GMT
References: <1138@nmtsun.nmt.edu> <862@ritcv.UUCP> <255@rna.UUCP> <4422@lynx.UUCP> <871@ritcv.UUCP>
Reply-To: hjortsho@cg-atla.UUCP (Erik Hjortshoj)
Organization: Compugraphic Corp. Wilmington, MA
Lines: 24

In article <871@ritcv.UUCP> cep4478@ritcv.UUCP (Christopher E. Piggott) writes:
>
>
>Question: why are R.G.B. monitors Red, GREEN, blue, when GREEN is not one of
>the primary colors (being a combination of blue and yellow)?  Why shouldn't
>it be red, YELLOW, blue?

You are confusing the primary PIGMENT colors with primary LIGHT colors.
Pigment's primaries are, indeed, red, blue and yeller.  If you mix them all
together you get black.

Light's primaries are red(it's not actualy red but I forget what), green and 
blue.  If you mix them all together you get white.

>Projection televisions work the same way ... is it possible to emit green,
>and blue 180 degrees out of phase with the blue component of the green, to
>cancel out the blue and the green and make yellow?  If not, how do you make
>yellow?

I don't remember, but it IS a mix of the primaries. (red-green maybe) 
A lot of intro physiscs books have diagrams of the mixes of both
pigments and light.  An encyclopedia would have it as well.

Erik H.