LED CRI - Learning Objectives
What is CRI?
The term CRI stands for Color Rendering Index and is calibrated against how colors appear against natural daylight. The challenge is that these
Since LED light sources do not mimic daylight, there is a need to have some metrics for comparison to familiar light sources of sunlight, incandescent and halogen. Lighting Facts is a good start, for more details consider the Kelvin, CRI, and TM-30 metrics.
R9 Color Rendering Test Colors
Color Rendering Index (CRI) indicates the ability of a light source to render color accurately. The problem is that the original 8 muddy colors, and the addition of 4 additonal colors are not enough to judge a light source's ability to accurately render all colors.
Sunlight and Halogen Incandescent lighting score 100 serving as the basis for color comparisons for values of CRI.
Regulations in California (Title 24) require 90 CRI or higher in Residential applications. Commercial projects often use light sources with 80 CRI or as low as 70.
As LED light source technology advances, the CRI is improving; however, it is important to learn about the color rendering and limitations of a particular light source before specifying or purchasing, since most light sources cannot be returned, because the wholesaler or retailer cannot tell how many hours the lamp (light source) has been used.
TM-30 Color Type Key:
A-Nature B-Skin C-Textiles D-Paints E-Plastics F-Printed Materials G-Color Systems
Lighting Facts - Comparing the numbers
DOE - Department of Energy