värvieraldusindeks

Värvieraldusindeks, often abbreviated as CRI, is a measure used to describe the ability of a light source to reveal the colors of various objects being illuminated by it. It quantifies how accurately the perceived color of an object under a specific light source compares to its perceived color under a reference illuminant, typically natural daylight or a blackbody radiator of similar color temperature.

A CRI value is given on a scale of 0 to 100, where 100 represents the ideal rendering of colors, meaning the colors appear as they would under natural light. A lower CRI value indicates that the light source is less effective at reproducing colors accurately, and objects may appear duller, washed out, or with a color cast. For instance, a light source with a CRI of 80 would generally be considered good for most general lighting applications, while a CRI of 90 or above would be preferred for situations where color accuracy is critical, such as in art galleries, retail displays, or medical examinations.

The CRI is calculated by comparing the spectral power distribution of the light source with that of a reference illuminant across a set of eight standard color samples. The greater the difference in how these samples appear under the two light sources, the lower the CRI. While CRI is a widely used metric, it has limitations, particularly in how it samples colors and its applicability to certain types of light sources or specific color renditions. Alternative color rendering metrics have been developed to address these shortcomings.