CrI

CRI, or Color Rendering Index, is a quantitative measure used to evaluate a light source’s ability to accurately reproduce the colors of illuminated objects in comparison to a natural or ideal light source, such as daylight. It is expressed on a scale from 0 to 100, with higher values indicating better color rendering capabilities. A CRI of 100 corresponds to the color rendering of natural daylight, providing the most accurate color reproduction.

Developed by the International Commission on Illumination (CIE) in the 1960s, CRI is primarily used in lighting design and quality assessments, especially in environments where color discrimination is critical, such as in art galleries, retail stores, medical facilities, and cinematography. The measurement involves evaluating the appearance of eight standard color samples under the light source compared to reference lighting conditions.

While CRI effectively compares the color rendering performance of different light sources, it has limitations. For example, it may not accurately predict color rendering for highly saturated colors or in specific application contexts. Furthermore, modern lighting technologies, such as LED lighting, often emphasize correlated color temperature (CCT) and high color rendering indices to improve visual comfort and color fidelity.

Despite its limitations, CRI remains a widely adopted standard in the lighting industry, serving as an important reference for understanding how a light source will influence the appearance of colors within a space. Recent developments and alternative metrics, like TM-30-18, aim to provide more comprehensive color rendering evaluations beyond the traditional CRI scale.