Abstract
Color is important in two quite separate fields – vision science and illuminating engineering. Because of specialization, few color vision researchers fully appreciate the concept of color rendering in illumination, a topic that is becoming critical as LED's transform the field of electric illumination. Human color perception informs us about the spectral reflectance characteristics of a surface, often providing useful information about its constituent materials. (For example, is that banana ripe?) Our perception of surface color is remarkably stable over a wide range of lighting conditions, from person to person, and throughout life, thanks to ongoing unconscious calibration processes. This stability was evolutionarily advantageous, developing to work well with natural lighting conditions. However, with other kinds of light sources, an object's appearance can differ from its color under natural lighting. This can happen when a source, though white, nevertheless has invisible narrow features in its spectral power distribution that interact with also-invisible details in a surface's spectral radiance factor, yielding a noticeable shift of color appearance. This error is avoidable through careful light source design, but there is a debate about whether this is needed. Some say that few people care about accurate color vision, while others argue that perceptual distortion can be psychologically disturbing and therefore lighting designers should avoid it when possible. To help resolve this debate, there is a need for additional human factors research to yield findings that can inform the development of improved standards for color rendering in illumination.