Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!mordor!sri-spam!ames!ncar!oddjob!gargoyle!att-ih!ihnp4!inuxc!iuvax!bsu-cs!cfchiesa From: cfchiesa@bsu-cs.UUCP (Christopher Chiesa) Newsgroups: comp.graphics Subject: Re: Naive Question About Primary Colors Message-ID: <2474@bsu-cs.UUCP> Date: 27 Mar 88 04:53:21 GMT References: <7871@oberon.USC.EDU> <7779@apple.Apple.Com> Distribution: na Organization: CS Dept, Ball St U, Muncie, Indiana Lines: 30 I read with interest the original not-so-naive question on choice of primary colors; wasn't going to post a response but after reading the preceding respon- ses reaching this node so far, I thought I'd add two cents' worth of hopefully helpful "layman's terms" information... RED, GREEN, BLUE are "ADDITIVE" primaries: they are used in situations where light is being emitted; i.e. where "if you were to do NOTHING, you'd have BLACK." Examples: three separate beams of light (one each R,G,B) superimposed on a white screen; color television. Conversely, MAGENTA, YELLOW, CYAN are "SUBTRACTIVE" primaries: they are used in situations where one light is being filtered to obtain a desired resultant color, or where a NEGATIVE color image will be produced. Examples: color film (transparencies; negative-image printing); color filters; four-color halftone printing process. I realize that this still doesn't explain the use of RED, YELLOW, BLUE as primaries, although I seem to recall from childhood (when I asked Dad, a professional-level photographer and Kodak researcher) that these are SUBTRAC- TIVE primaries... I usually see MAGENTA, YELLOW, and CYAN in commercial color PRINTED materials, but usually RED, YELLOW, and BLUE when dealing with PAINTING and other non-photographic art. Do any of you "I work with this every day" types have any clarification? I'd be interested in hearing about it. UUCP: !{iuvax,pur-ee,uunet}!bsu-cs!cfchiesa cfchiesa@bsu-cs.UUCP -- UUCP: !{iuvax,pur-ee,uunet}!bsu-cs!cfchiesa cfchiesa@bsu-cs.UUCP