When purchasing a light fixture, you’ll often find its CRI (Color Rendering Index) to help guide your decision. But if you’re not well-versed in lighting terminology, a CRI of 64 can be confusing.
Rated between 1 and 100, the CRI of a light source measures its ability to reproduce the colors of an object in comparison to a natural light source. The higher the CRI rating, the more accurately it is supposed to reproduce the colors it illuminates.
However, the measurement gets complicated when you consider the natural light source is a black body radiator at 2700k and it’s only based on eight specified pastel or unsaturated colors. Because of this, a light source can receive a high CRI even if it poorly reproduces bright or saturated colors. Incandescent bulbs receive a CRI of 100, yet they are far from ideal color rendering. And, vice versa, a light source can receive a poor CRI even if it works well with bright colors. For example, LEDs can accurately illuminate bright or saturated colors, but not always unsaturated colors. A low CRI for LED lighting can be misleading.
As an answer to the criticism surrounding CRI for LED color rendering, the Color Quality Scale (CQS) is an alternative method that may eventually replace CRI. Instead of only eight unsaturated or pastel colors, the CQS evaluates 15 colors that more accurately span the range of object colors. In addition, it considers factors including chromatic discrimination and human preference.
Until we adopt CQS as the standard, an ideal light source for color rendering should have a color temperature similar to daylight accompanied by a high CRI value. If you’re basing your lighting decision on a product’s CRI, consider the application of the fixture or contact an Access Fixtures lighting specialist.