abbreviation acrylic paint additive color bird black blue brown cmyk color model crt cathode ray tube color space color television color theory color triangle color wheel cone cell cyan dichromacy digital object identifier gamut green grey hue isaac newton key plate magenta marsupial opponent process optical density paint painting phosphor primary colors psychophysics purple rgb color model rgb color space ryb color model red srgb secondary color sensation spectrum subtractive color television tertiary color tetrachromacy trichromacy ultraviolet visual perception wavelength white yellow zinc oxide