What is CRI?
CRI (Coloring Rendering Index) is the color rendering index. This value says something about how colors are displayed by the light source compared to a reference source such as daylight.
Color accuracy and color temperature
White light is formed by light that has all the colors of the rainbow. Our eyes do not immediately notice if some colors are missing from the spectrum.
But if there is not a certain color in the light, we cannot see that color properly on a certain object.
That is why color fastness in lighting is as important as color temperature. If the light from a lamp is indicated as a 4000K lamp, but there is no red in the light at all, then red objects will also appear barely red, but very pale red. It is therefore extremely important for color recognition that all colors of the rainbow can be found proportionally in the color of the light.
The measure for color recognition is the CRI or Color Rendering Index. A value of 0 indicates that only one very specific color is present and 100 indicates that the color recognition corresponds to that of daylight.
This CRI is measured by measuring 8 matte colors and taking the average.
A CRI of 80 is considered good quality for commercial use and at home. For use in museums or in professions where colors are very important (painters, tailors, etc.), a CRI of 90 or more is required.