Intensive investigation is necessary to discern the metamerism in the tagmata of such organisms. Also the printing industry is affected by metamerism. The process is repeated until original and reproduction present an acceptable degree of metamerism. The quality of a simulator can be assessed with the CIE Metamerism Index. They are [[Metamerism (color)|metamers]] of that color. Such light sources may appear to be the same color; this effect is denominated "metamerism". Because of metamerism, it is possible to have quite different spectra that appear white. One color that arises from two different spectral power distributions is called a metamerism. However, metamerism in smaller items such as textile fibers, is more difficult to be solved. Furthermore, because of the differences in colorants, spectral matches are infrequent and metamerism often occurs. In each such class the members are called "[[Metamerism (color)|metamers]]" of the color in question. Metamerism describes the effect of different light spectrum distributions on the perception of color. In colorimetry, metamerism is a perceived matching of colors with different (nonmatching) spectral power distributions.