Vision and Color

Revision date: 03-01-2005 Newton, Young, Maxwell, and Schrodinger were all central figures in the history of color science [20]. This chapter brings up to date a previous version written by the color scientist Edwin Land, who was himself renowned as an inventor and founder of the Polaroid Corporation, but who maintained an active interest in the psychology of human color vision throughout his career. Land developed a series of intriguing and controversial demonstrations of color perception [25]. In a typical example, grayscale images of a scene were photographed through either a red or a green filter. The two positive black and white slides were then recombined on a projection screen, with one projected through a red filter and the other with no filter. Though this restricted the stimulus to only “red” and “white” illumination, the resulting display took on a wide range of varying hues – and importantly – tended to reproduce the colors of the original scene. Newton’s experiments with prisms led him to conclude that “the rays are not colored” and thus that color is a property of the observer [35]; and many demonstrations like Land’s have shown moreover that the sensation of color does not correlate in a simple way with the spectrum of light at each point in the scene, for it also depends fundamentally on the surrounding context. This chapter places such demonstrations within the context of general principles that are thought to have shaped the design of the visual system, and illustrates these with specific examples of the processes mediating color vision. For detailed reviews covering a wide range of topics in vision, The Visual Neurosciences edited by Chalupa and Werner [6] is highly recommended. Recent comprehensive discussions of color vision can also be found in Mausfeld and Heyer [31], and Gegenfurtner and Sharpe [10]. For basic data on color and its specification and measurement, Color Science by Wyzescki and Stiles [49] remains an invaluable resource, while more recent data are available through the Color and Vision database at www.crvl.org. Finally, the Viperlib Library at www.viperlib.org has become a central site for demonstrations and illustrations related to vision science.