Xref: utzoo sci.electronics:3923 rec.audio:8470
Path: utzoo!utgpu!water!watmath!clyde!att!pacbell!ames!ll-xn!adelie!munsell!atexrd!rdp
From: rdp@atexrd.UUCP (Dick Pierce)
Newsgroups: sci.electronics,rec.audio
Subject: Re: Looking for Blue LEDs
Keywords: blue blue blue, not yellow or red or green
Message-ID: <72@grace.atexrd.UUCP>
Date: 27 Sep 88 13:30:57 GMT
References: <1138@nmtsun.nmt.edu> <862@ritcv.UUCP> <255@rna.UUCP> <4422@lynx.UUCP> <871@ritcv.UUCP>
Reply-To: rdp@grace.UUCP (Dick Pierce)
Organization: EPPS (A Kodak Co.),Bedford,MA
Lines: 25

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?
>

There are two types of primary colors: additive and subtractive. Those systems
(such as TV screens) that create color by adding primaries together use the
additive primaries red green and blue. Mixing any two of these together 
gives you magenta (red+blue), yellow (red+green) and cyan (green+blue), all
three mixed together in egaul intensities gives white (or grey). Systems that
produce color by subtraction (such as full-color printing or color slides) use
the primary colors of magneta, yellow and cyan (sound familiar, eh?). By 
subtracting two of these primaries from white light, you get red
(-(magneta+yellow), green (-(cyan+yellow) and blue (-(cyan+magenta).

What this has to do with rec.audio is beyond me, but, what the hell.


-- 
Dick Pierce                                    EPPS, Inc.
(617) 276-7317                                 32 Wiggins Ave.
{kodak,ll-xn,sun,genrad}!atexrd!dpierce        Bedford, MA. 01730
--