It's complicated, but red, yellow, and blue are a "good enough" set of primary colors that they were used for a long time. CMYK is superior, but neither of them can reproduce every color that the human eye can see. Neither can RGB light, for that matter.
http://en.wikipedia.org/wiki/RYB_color_model -Christopher On Mon, Mar 19, 2012 at 3:02 PM, Russell Jones <russell.jo...@gmail.com>wrote: > I'm pretty sure that's not the whole story as pigments are subtractive > whilst light is additive. One can't take red, green and blue paint and make > any colour. IIRC. > > Russell > > > On 19 March 2012 16:10, Ian Mallett <geometr...@gmail.com> wrote: > >> On Mon, Mar 19, 2012 at 9:49 AM, Russell Jones >> <russell.jo...@gmail.com>wrote: >> >>> Great news :) I liked IYOCGwP and have mentioned it here before now. >>> >>> BTW, on page 34 of the new book you write "(Red, blue, and yellow are >>> the primary colors for paints and pigments, but the computer monitor uses >>> light, not paint.)" >>> >>> The primary colours for pigment and paint are cyan, yellow and magenta, >>> no? >>> >>> Russell >>> >> There is a "color space" that defines all possible colors. "Primary >> colors" are the colors we choose as basis vectors. Both red-blue-yellow >> and cyan-magenta-yellow are valid basis vectors; the former more often used >> in painting, the latter more often used in printing. >> Ian >> > >
