COLOR AND COLOR SPACES Douglas

“Color space” refers to a specific system of coordinates that allows us to describe a particular color of light. In this article we discuss the concept of the color of light and the concept of a “color model”—which if precisely specified is today most often described as a “color space”. We then describe in some detail a number of specific color spaces used in a wide range of fields. TABLE OF CONTENTS BACKGROUND .................................................................................... 2 Color ............................................................................................... 2 “Color model” and “color space”......................................................... 3 Luminance and related metrics ............................................................ 3 COLOR SPACE FAMILIES ...................................................................... 3 Luminance-chromaticity color spaces................................................... 3 The luminance-hue-saturation space ................................................. 3 The CIE xyY color space and the CIE chromaticity diagram.................. 4 Tristimulus spaces............................................................................. 5 Luminance-chrominance spaces .......................................................... 5 Chromaticity vs. chrominance............................................................. 6 GAMMA.............................................................................................. 7 COLOR SPACES FOR COMPUTER GRAPHICS.......................................... 8 The RGB space ................................................................................. 8 The HSV (HSB) space ...................................................................... 10 The HSL space................................................................................ 12 COLOR SPACES FOR TELEVISION IMAGES........................................... 12 Introduction .................................................................................... 12 The YUV color space ....................................................................... 13 The YIQ color space ........................................................................ 14 The YPbPr space ............................................................................. 15 The YCbCr space ............................................................................ 16 COLOR SPACES RELATED TO COLOR PRINTING ................................... 17 Three-color printing ......................................................................... 18