Exploring Light by Alexander Efron (review)

Books 297 LasersandLight. ReadingsfromScient$c American, with introductions by Arthur L. Schawlow. W. H. Freeman, San Francisco, 1968.376 pp., paperback, illus. $5.95. Reviewed by: Grace Marmor Spruch* Someyears ago sculptorHarold Tovishexpressed his enchantment with holograms: ‘The idea of sending an entire exhibition of sculpture in an envelope!’ Tovish had the advantage of proximity to the Massachusetts Institute of Technology and knewtherewasa lotinthe new scienceof holography for artists. Butwhat doesonewhoisfarfrom M.I.T. do? One thing is to read selected articles from Lasers and Light. Selected is used advisedly. Scient$c American isan excellentsourcefor the latestfindings in the different sciences. There is a catch, though, and that catch is embodied in the magazine’s title. One must be somewhat scientificto understand the articles. Most are not written for intelligentlaymen; they are written for medical men, engineers or scientistsin one field to learn about another. Lasers and Light-it should be Light and Lasers, for less than half the material deals with lasers-is no exception, even though the authors include two Nobel laureates and the master of making difficult physics comprehensible, Victor Weisskopf. Half a dozen articlesdo not require scientificbackground, however, and these alone artists might find worth the price of the book. One is an article on holography titled ‘Photography by Laser’ by Emmett N. k i t h and Juris Upatnieks. It explainsthe process that producesan image truly three-dimensional-to see a serial number underneath an object, one bends to look underneath the image. No wonder Tovish’s enthusiasm. Another is ‘The Control of the Luminous Environment’ by architect James Marston Fitch, which deals with problems of lighting. Glasses are available these days that filter, polarize, refract or focuslight in special ways, as, for example, one that is darkened by ultraviolet light, reversibly, so that it always transmits a fixed amount of sunlight no matter how much that sunlight changes. Not bad formuseumsandgalleries.Aplastic,usedonlighting iktures, eliminatesglareon lit surfaces. A prismatic glassdeliversdaylightto any part of a room, suchas onapainting,or puts the ‘fingerof God‘on an object the way baroque architects did. An articleon fiberopticsdescribeseffectsthat can be achieved with ‘light pipes’ that transport light around comers or funnel broad, weak beams into narrow, bright ones and vice versa. Articles by a psychologist and a physicianengineertreat perception. How do we tell distance and size? What falls on the retina and what is transmitted to the brain? What is a hallucination? Ulric Neisser, in ‘The Processes of Vision’, points out that the same word, image, is used for both the *Department of Physics, Rutgers University, 101Warren St., Newark.N . J .07102,U.S.A. pattern thrown on the retina by an object and the mental experience of ‘seeing’. Neisser includes an account of Descartes experimentally observing what falls on the retina. Descartes set an ox’s eye into a window shutter as if the ox were peering out, scraped the back of the eye to make it transparent, looked through it, and saw a small inverted image of the scene outside. As to what psychologists are up to today, Neisser illustrates how the brain makes a larger story from the limitedinput to the retina. When viewingan arrowshaped weathervane, it is difficult to tell whether a short arrow is at right anglesto the line of sight or a longer one is slanting toward or away from the observer. When the arrow turns in the wind we immediately know its shape, though the image on the retina at any instant is the same as the twodimensional image of the stationary arrow. E. LlewellynThomasdescribesexperimentswhere a subject wears apparatus that enables the experimenter to record exactly where he is looking. In a filmed knife fight the faces of the combatants commanded attention; the knives got only an occasional glance. In one experiment, the visual behaviorof anartist anda nonartistwascomparedas theyexaminedpaintings. Conclusion:manypainters are successful in directing the movements of our eyes. The artist appeared more sensitive to this, particularly with non-figurative subjects. The eyes of both were drawnto discontinuities,includingthe edgesof the picture. Otherexperimentsshowedthat in viewing a picture large areas never get a glance, even when we think we inspect the entire surface. Theremainingarticlesarenot a total waste. When Weisskopf tells us-in...