CEE 5244 Lecture Notes - Lecture 29: Photopic Vision, Cyan, Chlorophyll
5 Apr 2016
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Immediate bouncing of incident light (zero delay: very occasionally we see light that has been absorbed, then re-emitted at a different wavelength. Called fluorescence, phosphorescence, luminescence: colors, light is characterized by frequency, or more commonly, by wavelength, visible light spans from 400 nm to 700 nm. Or 0. 4 m to 0. 7 (cid:1)(cid:2)(cid:3)(cid:4)0. 0004 mm to 0. 0007 mm, etc: white light, white light is the combination of all wavelengths, with equal representation. Red hot poker has much more red than blue light. Experiment: red, green, and blue light bulbs make white. Why? because absence of green is magenta. Absence of red is cyan, etc: subtractive colors, but most things we see are not light sources, reflection takes away some of the incident light. Thus the term subtractive: if incident light is white, yellow is absence of blue, what"s responsible for selective absorption, carotene. Makes carrots orange, tomatoes red, daffodils yellow, leaves turn. Must absorb blue light: long, organic molecular chain.
