Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site pyuxt.UUCP Path: utzoo!watmath!clyde!burl!ulysses!gamma!pyuxww!pyuxt!marcus From: marcus@pyuxt.UUCP (M. G. Hand) Newsgroups: net.physics Subject: Re: colors Message-ID: <161@pyuxt.UUCP> Date: Mon, 6-Aug-84 22:54:16 EDT Article-I.D.: pyuxt.161 Posted: Mon Aug 6 22:54:16 1984 Date-Received: Wed, 8-Aug-84 19:26:55 EDT References: <354@ism780.UUCP>, <3798@brl-tgr.ARPA> Organization: Bell Communications Research, Piscataway N.J. Lines: 20 > There is a pure green spectral line, so it is not a mixture. > By the way, mixing blue and yellow light is more likely to > give white, light blue, or light yellow than green for most > people. No, no, no! The hue green can be produced by a single specral emission, by a narrow band spectrum, a broad band spectrum or by a mixture of wavelengths which don't include the green spectral line. The eye and brain are not sophisticated enough to determine the components of the hue in isolation, although the purer the light the more intense it appears (Not "bright", intense - this is a saturation effect because it is not watered down by other specral emissions.) The addition of the two coloured light sources blue and green probably will produce a whitish hue because most light sources which people have access to have fairly broad band spectral outputs; ie, its yellow because of the absence of the blue end of the spectrum rather than any strong yellow spectral content. Any book on colour photographic printing will give lots of good info. Marcus Hand (pyuxt!marcus)