CRI means the ability of the light source to visualize the object,which is compared with the color of the object under the same color temperature or appearance color of object under light source (incandescent or painted light). The spectrum emitted by light determines the color of the light source. But light color can be composed of many small or even two monochromatic light waves,and the color rendering to different object is various. The same color of the light source will have different spectral composition, light sources are more likely to provide better color quality when spectral compositions has a wider range. The color rendering index coefficient (Kaufman) is still a general method for the current definition of light color rendering.


Color is divided into two kinds:
Faithful color: the correct expression of the original color of the object need to use light source color rendering index (Ra) high, the value close to 100, it is the best color.
Effect of color: to highlight the specific color, the good performance of life can be shown by enhancing the color effect. Using a low color temperature light source can make the red more vivid, and when we use medium color temperature light source, the blue has a cool feeling; using high color temperature light source makes the object has a cold feeling.
The relationship between color rendering index and color rendering
When the main wave which is reflected by original light source are rare, the color will appear a clear color shift. The greater the degree of color, the worse the light source of the color. The color index coefficient (Kau fman) is still a general method for defining the color rendering of light sources.