A physicist's view of light, the most pervasive form of energy in our universe, and a force that has shaped human life and consciousness from the very beginning. From the outset, Perkowitz (Physics/Emory Univ.) shows not only an ability to express his subject clearly, but a fine awareness of light's appeal to our esthetic senses. After a quick glance at the many instances of light in his life—from the huge lasers with which he works to the emotional impact of colored light in such films as The Wizard of Oz—the author turns to the complex physiological process of perceiving light and color. The range of vibrations in visible light is comparatively narrow, less than a tenth of what a modest stereo system can produce in terms of sound vibrations. Our nervous system makes up for that apparent narrowness with a series of ingenious adaptations: The cone cells in the retina respond only to motion, whereas the rods embody all our awareness of color. They feed their data to the visual cortex, which contains ten times the number of neurons as the auditory system. Interpreting and explaining what we see has occupied science since the earliest days, when it was widely believed that the eye itself generated a beam of light that made vision possible. At the same time, artists were pursuing their own investigations of light, from Caravaggio's dramatically darkened scenes to Renoir's electrically lit interiors to van Gogh's rapt evocations of natural light and color. A fascinating chapter looks at how various chemicals alter the composition of light to produce the colors we see, both in the natural world and in painting. Invisible light—infrared, ultraviolet, X-ray—plays a role in the story, as well. Perkowitz knows when to connect a scientific summary with a mundane example and shows a fine appreciation for the link between the physicist's and the artist's views of light. Smoothly written, comprehensive, and thoroughly enjoyable.
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