Low pressure sodium lamps emit all visible energy at 589 and 589.6 nanometers, which means that they can render only materials that reflect light at 589-589.6 nanometers. All other colors appear gray. The color characteristics of light have a significant effect on the appearance of people. HID and some fluorescent sources that emphasize the yellow or blue range produce a sallow or pale appearance. The color of light can also affect subjective impressions of brightness.
Experiments indicate maximum and minimum desirable illumination levels for each color temperature.
It suggests that warmer light is desirable for low brightness levels. With the warm-toned kerosene source, the level would seem too high and the space too bright. With simulated daylight, on the other hand, the same lighting level would seem dark and dingy. Choosing a lamp color is not simple, but it is critical to the success of an installation. Common sense suggests the importance of the relationship between the color of light and the colors of fabrics, walls, and other elements in the decorative scheme.