Small knowledge of LED lamps – CRI

What is Color Rendering Index (CRI)?
The color rendering index of the light source refers to the parameter of the ability of the light source to restore the color of the object. It is mainly used to define the color difference of the LED light source. The score of this index is 0-100.

To put it simply: color rendering is an important aspect of evaluating lighting quality, and color rendering index is an important method to evaluate the color rendering of light sources, and is an important parameter to measure the color characteristics of artificial light sources. The better the color, the stronger the ability to restore the color of the object.

The International Commission on Illumination (CIE) defines color rendering as: the effect of a light source on the color appearance of an object compared with a standard reference light source.

General color rendering index: the larger the Ra, the better the color rendering performance; otherwise, the worse the color rendering performance. The color rendering index of sunlight is defined as 100.

Although "color rendering index" does not represent all of a lamp. But "high CRI" can largely determine the effect of lighting - high color reproduction.

As shown in the figure below: the light source with index index (Ra)>90 is stronger than the light source with index index (Ra)<80 to present the natural primary color of the object, and it is more comfortable visually.

The International Commission on Illumination (CIE) sets the color rendering index of sunlight as 100, and stipulates 15 test colors, and uses R1-R15 to represent the display indexes of these 15 colors. When comparing a light source to a specified reference light source, an index value of 100 is best.

Generally speaking, Ra refers to the average value of the light source for the eight natural color reproduction levels of R1-R8, and R9-R15 is not counted. But from a professional point of view to evaluate the CRI of the light source, you should consider the parameters of R9 (for red reduction) and R15 (for Asian skin color performance).


Since the LED lamp is produced by the blue chip to excite the yellow phosphor to produce white light, it is extremely lacking in the red band, resulting in the LED lamp having no red display capability. When we choose LED lamps, we should not only look at the color rendering index Ra, but also the values of R9 and R15. It is recommended that Ra>90 (R9>50, R15>90) be displayed for general lighting indicators.

The difference in color rendering index:

90-100 Places that require precise color contrast, such as museum lights;

80-89 Places where correct judgment of color is required;

60-79 Places requiring medium color rendering;

40-59 places with low requirements for color rendering and small color difference;

20-39 Places without specific requirements for color rendering.


In home lighting design, to create a healthy and good atmosphere, it is particularly important to choose the right light source and lamps. In order to make the light show people's complexion better in life, and the color of food and fruit is realistic, when choosing lamps, it is necessary to choose the higher the display index, the better, that is, the RA value (R9, R15) must be high.

The national standard stipulates that the minimum color rendering index RA of indoor lighting fixtures is 80. However, Luo Hualu, the lighting designer of Mizhi Space, pointed out that from the principle of healthy use of light, we require the RA to be greater than 90 when designing lighting and matching products. The best light is natural light, and its color rendering index is defined as 100. At present, the best lamps and lanterns in the world can only be infinitely close to 100.

The dangers of low color rendering index
The "Hygienic Standards for Lighting and Lighting in Classrooms of Primary and Secondary Schools" pointed out that the color rendering index of classroom lighting sources should not be less than 80. The color rendering index of classroom lighting that is too low affects the students' recognition of the color of the object by the eyes, so that the object cannot show its true color. If this situation continues, it will lead to the decline and decline of color discrimination ability, resulting in color blindness and weak color of students and other serious vision problems and eye diseases.

Optometry has repeatedly confirmed one thing, natural light can prevent myopia. From the perspective of protecting eyesight, it is the right choice to choose high-resolution lamps, especially desk lamps for children. Items such as children's books and toys are colorful. If you choose a desk lamp with a low CRI, the color reflected back to the children's eyes will lose saturation, resulting in color distortion, easy to cause visual fatigue, and may lead to myopia.

Therefore, choosing lamps with high CRI is often good for light perception and vision.

Summary: Why choose High Significant Index?

1. High color reproduction: high color saturation.

2. Prevent myopia.

3. To meet the needs of users.

Solve the pain points of users: things are not real under the light, and protect children's eyesight.