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Chapter 27. Color. Selective Reflection. Atoms absorb light at or near their natural frequencies. Atoms reradiate light at other frequencies. Leaves must absorb everything that is not green. Petals must absorb everything not red. Different Illumination.
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Chapter 27 Color
Selective Reflection • Atoms absorb light at or near their natural frequencies. • Atoms reradiate light at other frequencies Leaves must absorb everything that is not green Petals must absorb everything not red.
Different Illumination • What color are the petals of the rose under blue light? • Black • What color are the leaves under green light? • Green
Selective Transmission • Color of a transparent object is the color of the light it transmits. • Blue glass appears blue because it absorbs all other colors.
Simplified Radiation Curve Real spectral colors Simplified Wavelength
CYAN MAGENTA YELLOW Color Addition These mixtures are the subtractive primary colors
Memorize these! Yellow Magenta Cyan White Play mixing the colors yourself
Traditional Color Wheel Colors equally spaced are said to be primary : Red-Yellow-Blue (RYB) or sometimes Violet-Orange-Green (VOG). neither RYB nor VOG is equidistant on a perceptually uniform color wheel RYB cannot mix all colors and we will not consider it further
Complimentary Colors B + G G + R B + R
XX YellowFilter Blue Filter XX XX Color Subtraction White Light Black
Cyan Light XX Yellow Dress Green Dress Color Subtraction
Magenta Light XX Yellow Dress Red Dress Color Subtraction