What is Color Rendering Index

Some thing about Color Rendering Index

 

CRI-WAHLL Lighting 

 

In our life, we often encounter a scene: an apple under different light source present different color. A person’s skin show differences with real color under different indoor lighting. Hotel and restaurant use slant red light to create a warm environment. Office and factory purpose slant blue light etc. These examples are closely related to light color rendering.

Long time ago, humans have begun comparing color. They were usually put objects together to observe under the natural light (sunlight). Although incandescent light, torch, candle, and other light sources can be used for lighting, but people are used to compare color under natural light (sunlight).

Objects under the sun, will show its true color. But when the object under a florescent lamp, HID light, LED lights, the irradiation of color will have different degrees distortion. We name light source peformance real color rendering level as color rendering index.Simple as CRI. When CRI is calculated, it can be rated on a scale from 0 – 100. And it’s unite is Ra, The best performance is 100. We call close to natural light (sunlight)’s hue, the light source has a good color rendering index(high).

According to different application field, CIE divide color rendering index into five general categories:

1A, Ra> 90 Art gallerie, museum and printing industry.
2B, Ra=80-90 Family, restaurant, advanced textile technology, and similar industry.
2, Ra=60-80 Offices, schools, outdoor street lighting.
3, Ra=40-60 heavy industry factory, outdoor road lighting.
4, Ra=20-40 outdoor road lighting and some requirement low place.

Color Rendering Index