PSC 131 Lecture Notes - Lecture 9: Sodium-Vapor Lamp, Electromagnetic Spectrum, Additive Color
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I. lecture 9 color (may 3, 2017) Demo: low pressure sodium lamp: color is totally mental! a. Low pressure sodium lamp emits only one wavelength of light. Everything looks like the sepia filter! a. b. We turned off all other light and only allowed the yellow light to come through c. only yellow items appeared yellow because the light reflected into our eye is yellow d. all other objects were some shade of gray. C. color and light: color signals help us classify and identify objects, color facilitates perceptual organization of elements into objects a. Color vision may provide an evolutionary advantage in foraging for food. Visible light wavelengths between 400-700 nanometers b. c. ultraviolet below 200 nanometers (sunburns us) Infrared spectrum in range of 1,000-100,000 nanometers (felt as heat) Actually, there are no colors out there in the world. Color is not a physical property but a psychophysical property. b.
