ABSTRACT
Colorimetry, the measurement of color, attempts to quantify the perception of color. Ultraviolet radiation is important to colorimetry because it can cause fluorescence. Infrared radiation is the basis of "heat lamps" but is not important in colorimetry. Spectroradiometers measure the spectral power distribution of light sources. Basic colorimetry provides the rather simple concept of dealing with the measurement of single independent colors. Most of industrial color control is adequately described using basic colorimetry. Advanced colorimetry attempts to use physical measurements to describe the perceived color of a material when viewed in a complex scene. Materials that contain metallic and/or pearlescent pigments are goniochromatic, that is, they change color with the illuminating and viewing geometry. Goniospectrophotometers are needed to measure these materials. Spectral radiometers and radiometric colorimeters were designed to measure lamps, light sources, and displays. These instruments are similar to spectrophotometers and colorimeters but do not need an illuminator, because the sample being measured emits light.
