BetterPhoto Q&A
Category: Traditional Film Photography

BetterPhoto Member		Photography what are the two color theries that use RGB and CMY as their primary colors? To love this question, log in above April 23, 2007

Alan N. Marcus		Hi Kevin, The additive primaries Red – Green – Blue: Applied superimposed or adjacent. Applicable to light sources such as spot lights –TV – Computer Monitors – i.e. devices that display images via shining light onto a screen or stemming from a screen. R + B + G = White (presence of light all three colors) R + B = Magenta a subtractive primary or white minus green R+ G = Yellow a subtractive primary or white minus blue B + G = Cyan a subtractive primary or white minus red -R – B – G = Black (absence of light) The subtractive primaries Cyan – Magenta – Yellow: Used when ink or dye or pigment are applied to white paper or canvas. Must be applied adjacent as unique points of color. Cannot be applied superimposed because any two superimposed yields black. If applied adjacent: M + Y + C = Black M + Y = Red M + C = Blue C + Y = Green - C – M – Y = White Alan Marcus ammarcus@earthlink.net To love this comment, log in above April 23, 2007

Alan N. Marcus		I made an error: Cannot be applied superimposed because any two superimposed yields black. This is wrong. It should read because any three superimposed yields black. The subtractive primaries are use both in negative color film and positive slide film. Three layers of dye are used. The top layer is cyan – the middle layer is magenta – the bottom layer is yellow. Dye in any two layers causes an overlap. Thus: Magenta + Yellow = Red Cyan + yellow = Green Cyan + magenta = Blue Cyan + magenta + yellow = Black Sorry of the error! Alan Marcus ammarcus@earthlink.net To love this comment, log in above April 23, 2007

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