Värviedastusindeks

Värviedastusindeks, often abbreviated as CRI or Ra, is a quantitative measure of a light source's ability to reveal the colors of various objects faithfully compared to an ideal or natural light source. It is a system developed by the International Commission on Illumination (CIE). The index is a value between 0 and 100, where a CRI of 100 indicates that the light source renders colors perfectly.

Lower CRI values suggest that the light source may distort the colors of objects, making them appear different from how they would look under natural daylight. For instance, a light source with a low CRI might make red objects look duller or shift blues towards green. The CRI is determined by comparing the spectral power distribution of the light source to that of a reference source, typically a blackbody radiator that matches the correlated color temperature of the source being tested.

The CRI is calculated using a series of standardized color samples. The accuracy of color rendition is assessed by comparing how these samples appear under the test light source versus the reference source. While a high CRI is generally desirable for applications where accurate color perception is important, such as in retail, art galleries, and photography studios, it's not the only factor to consider when choosing lighting. Other factors like energy efficiency and color temperature also play significant roles.