What is the color rendering index?

The color rendering ability of a light source to an object is called color rendering, which is compared with the color of the object appearance under the same color temperature reference or a reference light source (incandescent lamp or picture light). The spectral content emitted by the light determines the light color of the light source, but the same light color can be formed by many, a few or even only two monochromatic light waves, and the color rendering of each color is also very different. Light sources with the same light color will have different spectral compositions, and a light source with a wider spectrum composition is more likely to provide better color rendering quality. When there is little or no reflection of the main wave in the light source spectrum under the reference light source, the color will produce a significant color shift. The greater the degree of color difference, the worse the color rendering of the light source is. The color rendering index coefficient (Kaufman) is still the universal method for defining the color rendering evaluation of the current light source.

Color rendering Two types of faithful coloration can correctly represent the original color of a substance. A light source with a high color rendering index (Ra) is required. The value is close to 100, and the color rendering is the best.
The effect coloration should clearly emphasize the specific color, and the life that expresses the beauty can use the additive method to enhance the color rendering effect. The use of a low color temperature light source can make the red more vivid; with a medium color temperature light source, the blue has a cool feeling; using a high color temperature light source, so that the object has a cold feeling.

The relationship between color rendering index and color rendering When there is little or no reflection of the main wave in the light source spectrum under the reference light source, the color will produce a clear color shift. The greater the degree of color difference, the poorer the color rendering property of the light source is. The Kau fman coefficient is still the universal method for defining the color rendering of light sources.

The color rendering index of an incandescent lamp is defined as 100, which is considered an ideal reference light source. This system uses 8 kinds of medium-colored standard color samples to test, compare the degree of deviation (Deviation) under the test light source and the same color temperature reference, to measure the color rendering index of the light source, and take the average deviation value. Ra20-100, with 100 as the highest, the greater the average color difference, the lower the Ra value. Light sources below 20 are generally not suitable for general use.

Index (Ra) Grade Color Rendering General Application 90-100 1A Excellent Locations Where Color Exact Contrast Is Needed 80-89 1B Places Where Color Requires Correct Determination 60-79 2 Places Where Normal Color Rendering Is Needed 40-59 3 Pairs Color Rendering The requirements of sexuality are lower, and the color difference is smaller. 20-39 4 The location of poor color rendering has no specific requirements The theoretical color rendering index of incandescent lamp is 100, but there are many kinds of incandescent lamps in real life, and the application is also different. So its Ra value is not exactly the same. Can only be said to be close to 100, is the best color rendering lamps. The Ra value of a specific fixture can be seen in the table below.
Light source color rendering index Ra
Incandescent lamp 97
Daylight fluorescent 80-94
White fluorescent lamp 75-85
Warm white fluorescent 80-90
Tungsten halogen lamp 95-99
High pressure mercury lamp 22-51
High pressure sodium lamp 20-30
Metal halide lamps 60-65
Sodium Indium Indium Lamp 60-65
Xenon lamp above 85