Värintoistoindeksi

Värintoistoindeksi, or Color Rendering Index (CRI), is a measurement of how accurately a light source reveals the true colors of objects. It is a quantitative measure of the ability of a light source to reproduce the colors of various objects faithfully compared with an ideal or natural light source.

The CRI scale ranges from 0 to 100. A CRI of 100 indicates that the light source renders colors perfectly, as they would appear under natural sunlight. As the CRI value decreases, the light source's ability to accurately reproduce colors diminishes. For instance, a light source with a CRI of 80 will show colors that are reasonably accurate, while a CRI of 50 suggests a significant deviation in color perception.

The CRI is determined by comparing the spectral power distribution of the light source in question to that of a reference illuminant. The reference illuminant is typically a blackbody radiator (like sunlight) whose correlated color temperature matches that of the test light source. The color differences between objects illuminated by the test source and the reference source are then averaged to produce the CRI value.

Different applications have varying CRI requirements. For general indoor lighting, a CRI of 80 or higher is often recommended. In applications where accurate color reproduction is critical, such as art galleries, museums, and some retail environments, a CRI of 90 or above is preferred. Low CRI light sources can distort colors, making them appear washed out, unnatural, or even completely different from their true appearance.