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What is color rendering index (CRI) and how do we choose it?

When buying lighting products, we take into account their appearance, functionality, and core parameters. One essential parameter to consider is the color rendering index (CRI), which measures how accurately a light source displays the true colors of an object. In this guide, you will learn about what CRI is and, more importantly, how to choose the appropriate CRI for your lighting fixtures.

What is Color Rendering Index (CRI)?

Color Rendering Index (CRI), also known as Ra, is an indicator developed by the International Commission on Illumination (CIE) that represents the color rendering effect of a lighting object. Generally, we refer to objects with high CRI as having good color rendering. The higher the CRI, the better the color rendering effect, and the more accurately the colors of the object being captured are reproduced. This is what we usually refer to as good color rendering. When selecting lighting fixtures, CRI is a crucial factor to consider.

The color rendering index (CRI) differs between natural light and artificial light sources. The general CRI for natural light is 100, while incandescent and halogen lamps have a CRI of around 97. The CRI for tri-phosphor fluorescent lamps generally falls between 80 and 90, and for LED lights, it is even lower, between 70 and 90.

However, if you truly care about color rendering, it is important to consider not only the general CRI (Ra) but also two other indicators: fidelity index (Rf) and color saturation (Rg).

Rf ranges from 0 to 100, with 100 being the highest value, indicating no color difference from natural light and the most realistic color rendering. On the other hand, Rf at 0 indicates the maximum color difference from natural light and the most distorted color rendering.

Why is Color Rendering Index (CRI) so important?

There are multiple reasons why it is essential to take the color rendering index (CRI) into consideration when buying lighting fixtures. While aspects such as color temperature and wattage are important, the CRI is just as significant. In cases where two fixtures have identical color temperature and wattage, differences in CRI can significantly impact the appearance, tone, and overall atmosphere of illuminated objects. Therefore, it’s vital to consider CRI to achieve accurate and natural-looking colors and to create the desired ambiance.

How to choose the appropriate CRI for your lighting project?

When choosing LED lights, two principles should be considered for color rendering: the principle of accurate color rendering and the principle of artistic effect color rendering.

Generally speaking, Ra>90 indicates excellent color rendering performance, almost equivalent to natural light. Such fixtures are suitable for places that require extremely high color discrimination, such as printing, dyeing, and inspection. Ra80-90 indicates very good color rendering performance and is suitable for illuminating colored TV broadcasts, display exhibits, and other similar applications. Ra 65-80 indicates good color rendering performance and is generally used for indoor lighting. Ra50-65 indicates moderate color rendering performance and is typically used for outdoor lighting. Ra<50 indicates poor color rendering performance, and such fixtures are only suitable for places with low color requirements, such as parking lots and warehouses.

CRI
category
RaEffectsApplication places
1A90-100ExcellentArt galleries museums
1B80-89GoodPrinting, painting, fiber and precision work factories; residential houses, hotels, restaurants
260-79OrdinaryFactory for general operations such as electromechanical assembly, surface treatment, control room, etC.; office and study are also allowed
340-59Not goodHeavy industry factories such as machining, heat treatment, casting, etc.. outdoor streets
420-39badWarehouse lighting, build a metal warehouse, outdoor street lighting

Color rendering index standards for sports lighting

To achieve better viewing and broadcasting effects, the quality of sports lighting not only depends on illuminance, but also on color temperature and color rendering. Meeting the illuminance standard only allows us to “see clearly”, while meeting the color temperature and color rendering standard allows us to “see well”.

For television broadcasting, the color rendering index (CRI) of the general light source should not be less than 65. In addition, according to the requirements of the International Football Federation, the light source color temperature (Tc) should be greater than 5000K and the CRI should be greater than or equal to 80. This means that in the lighting design of sports venues, the light source color temperature should be higher than 5000K, and the CRI should be at least Ra>65.

Buy High CRI LED Lights from ENCORE Lighting!

ENCORE is one of the LED lighting manufacturers  that has helped many designers, artists, and contractors build their lighting projects from scratch.We offer lighting products with high color rendering index, high power, and high quality, as well as professional lighting design and optical solutions.

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