Color effect of light sources on peridot based on CIE1976 L*a*b* color system and round RGB diagram system.

Previous research indicated that the peridot's color is dominated by the selective absorption of visible light caused by ferrous ion, the hue angle of which is in an inverse ratio of the concentration of Fe2+. This article focuses on the color effect of peridot under different standard light sources based on the CIE1976 L*a*b* color space system and round RGB diagram system and tries to find the best one for its grading and display. Based on the results of a series of experiments, including electron microprobe analysis, spectrophotometer, UV‐Vis spectrum, standard illumination box, and Munsell neutral color chips, it was suggested that the spectral power distribution and color temperature of a standard light source significantly influence the color of peridot in terms of lightness and chroma, particularly in the hue of peridot. As for color grading and displaying of peridot, standard light source A fails to fit in, and the color of peridot under a fluorescent light source has a higher chroma but a lower hue angle than that under daylight light source. The best choice for grading and displaying peridot is the standard light source D65. It is better to distinguish the hue of peridot when it is calculated by the round RGB diagram system. [ABSTRACT FROM AUTHOR]