The color qualities of a lamp are characterized by two different aspects, color temperature, and color rendering. color rendering is the ability of a lamp to give a good color representation of the object it is illuminating. color rendering is measured in a scale from zero to 100 are a color rendering index. The ability of lot to reveal colors c r, and the symbol are a excellent color rendering is numbered at 100 are a good color rendering Is 80 to 90 are a hand moderate color rendering is 60 to 80 Ra. Below this would be classified as low quality, CRI color rendering index. This scale represents how close the color rendition of the light source is against true white lat or true light natural daylight.

Some lamps have better color rendering than others, and should be selected for the color critical applications. A surface or object under a high pressure sodium vapor lamp commonly used for street lighting or carpark lighting has a measure of 20 Ra, which will appear more yellow than they would under natural daylight but a surface or object under 100 Land, which has a measure of 100 ra would in theory appear as if it were under natural daylight. Generally, lamps with a color rendering index si ri below ad should not be used in interiors where people were or stay for long periods of time.