Color rendering index (CRI) is the characteristic of a light source to reveal the color of an object when compared with a reference standard light source. In simple terms, it represents the extent to which the light source reproduces a given color. The better the color rendering of a light, the more realistic the colors of the illuminated objects are.

As stipulated by the International Commission on Illumination, the color rendering index ranges from 1 to 100, and the sun’s color rendering index is set to 100, which is to say, the original color of an object is the color it appears in sunlight. The color rendering index of the light sources that we commonly used is generally above 80. Some of the high-quality luminaires can reach 90 or even 95, close to the color rendering of sunlight. Fig. 1.4.1 displays the color performance of an interior space under two color rendering light sources Ra80 and Ra95. Luminaires with high color rendering index can add charm to your home.