Colors appear differently under different light sources, and the Color Rendering Index (CRI) measures a lamp’s ability to render colors most naturally. It measures the degree of color shift objects undergo when illuminated by a reference source of comparable color temperature. If you’ve ever held up a pair of pants in a store window to see whether they were black or navy blue, then you’ve noticed the difference in the color rendering of the store’s light bulbs and natural sunlight.

CRI is measured on a scale of 0 to 100, with daylight being 100. Generally, the higher the CRI, the better the colors appear. The color rendering property of lamps is extremely important in many applications, especially retail stores, museums, galleries, etc.