Colour Rendering Index

Colour rendering index (CRI) is a quantitative measure of how accurately an artificial light source displays colours. CRI is determined by comparing the appearance of a coloured object under an artificial light source to its appearance under incandescent light. The higher the CRI, the better the artificial light source is at rendering colours accurately. High (above 80) CRI is generally preferred in the home. (ENERGY STAR).

Though CRI and Colour temperature are related, they do not address the same properties with respect to the colour performance of a lamp. CRI is concerned with how effectively the light from a lamp renders colours in various objects and materials. Colour temperature is an indication of the colour appearance of the light source and the light emitted from it. When comparing the CRI specification for two different lamps, both must have the same colour temperature in order for the comparison to be meaningful.