color色彩讲解 （英文版）.pptVIP

Color Physics of color Electromagnetic radiation (James Clerk Maxwell, Heinrich Hertz. ) Wavelength / frequency intensity visible light spectrum 380-750nm Visible light spectrum Color perception Newtons law ： light was identified as the source of the color sensation. In 1810, Goethe published his comprehensive Theory of Colors. In 1801 Thomas Young proposed his trichromatic theory, based on the observation that any color could be matched with a combination of three lights. This theory was later refined by James Clerk Maxwell and Hermann von Helmholtz（1856）. Ewald Hering developed the opponent process theory of color, noting that color blindness and afterimages typically come in opponent pairs (red-green, blue-yellow, and black-white). 1957 by Hurvich and Jameson, who showed that retinal processing corresponds to the trichromatic theory, while processing at the level of the lateral geniculate nucleus corresponds to the opponent theory. In 1931, Commission Internationale dEclairage (CIE) developed a mathematical color model, which mapped out the space of observable colors and assigned a set of three numbers to each. Color in the brain Nonstandard color perception Color deficiency/Color blindness Tetrachromacy(not trichromatic) some species of spiders most marsupials, birds, reptiles many species of fish Synesthesia, grapheme–color synesthesia music–color synesthesia Afterimage Afterimage Color constancy It’s all in your head So, color is psychological Most people have the same cones, but there are some people who don’t – the sky might not look blue to them (although they will call it “blue” nonetheless) But many people (mostly men) are colorblind, missing 1,2 or 3 cones (can buy cheaper TVs) Primary colors (R,G,B) related to cones, not physics Describing Color Brightness: overall intensity Hue: dominant wavelength Saturation: how much other stuff mixed in with hue Hue + Saturation = Chromaticity Almost like: sum, mean, and std. deviation… Additive and S