Color Rendering Index plays a very important role in lighting applications. How to better restore the color of the object illuminated by the light, depending on the CRI value. If you are a lighting designer and you are designing a store, hotel, home, office, or art gallery, then it is very important for you to understand CRI.
This blog covers everything you need to know about CRI, such as what CRI is, the impact of CRI on product price, and how to choose the right CRI led lights for different applications.
1. What is CRI?
The Color Rendering Index (CRI) is a standard for quantifying the color reproduction ability of luminaires, with a CRI value ranging from 0 to 100. The higher the CRI, the closer the color of the luminaires is to natural light, and the stronger the color reproduction ability. This means that the color of the object itself can be more accurately reproduced.
2. How to measure CRI?
The CRI standard was first proposed in 1965, and was revised twice in 1965 and 1995. CRI test is divided into CRI (Ra) and CRI (Re), and its calculation formula is based on the average color rendering of the light source to the standard color sample. The difference between CRI (Ra) and CRI (Re) is that the number of slabs at the time of testing is different, CRI (Ra) is 8 slabs, while CRI (Re) is 15 slabs.
However, you can determine the CRI value in the following simple way.
The method of calculating CRI, using the integrating sphere test can get the accurate CRI value, the test time is about 1 minute, you can quickly get the CRI value.
Compare the CRI method, you can compare the color of the object illuminated by the light in sunlight, the closer the color, the higher the CRI value.
3. The importance of CRI
High CRI led light plays an important role in many fields and scenarios, mainly in the following aspects:
3.1. Accurate color rendering
High CRI led lighting reduce color distortion, making the color of the object look more natural and realistic. It is especially suitable for places with high color reproduction requirements, such as museums, galleries, hospital operating rooms and high-end retail stores. In these venues, accurate color presentation is essential for the preservation of cultural relics, the display of artworks, medical operations, and the display of merchandise.
3.2. Improve visual comfort
In interior lighting, high-CRI luminaires can provide a more comfortable visual environment. People work or live for a long time in such an environment, and their eyes are not easy to feel tired, which helps to improve work efficiency and quality of life.
4. Similar indicators of CRI
In addition to paying attention to CRI when you measure the color quality, there are other indicators that can help you determine, the following is to introduce you what is Rf and what is Rg.
In order to better measure the reduction ability of color, the Illuminating Engineering Society of North America officially released a new evaluation method for the color rendering ability of light In 2015, in order to better measure the color reproduction ability, the North American Lighting Engineering Society officially released IES, which is a new light source color rendering ability evaluation method IES-TM-30
Compared with CRI test method, IES test method is more difficult. Not only the color samples are directly increased from 8 to 99, but also the light source color is evaluated by Rf (fidelity) and Rg (saturation) dual indicators.
Rf (Fidelity) represents the degree to which 99 standard colors are similar under exposure to a test light source compared to a reference light source. Rg (saturation) represents the change in saturation of 99 standard colors in the test light source compared to the reference light source. (100 means identical; 0 means big difference).
5. Limitations of CRI
While a high CRI plays an important role in many areas, it’s important to note that CRI is not the only metric, for several reasons.
5.1. Limited scope of application
The CRI calculation is based on eight standard color samples, so it does not fully reflect the color rendering ability of the light source for all colors.
5.2. Affected by color temperature
Effective evaluation of CRI depends on the color temperature of the light source. The color point of the light source should be close to the blackbody radiation trajectory. This means that at certain color temperatures, the CRI may not accurately reflect the color rendering performance of the light source.
5.3. Lack of saturation information
CRI mainly reflects the color rendering of the light source for a small segment of medium saturation color, while the color rendering of high saturation color cannot be accurately evaluated.
6. The effect of high CRI
Although high CRI lighting products can bring you a lot of important roles, but when choosing high CRI products, you should also consider the following aspects.
6.1. The effect of luminous flux
Luminous Flux is a physical quantity that describes the total amount of light emitted by a light source. In most cases, the higher the CRI value, the lower the luminous flux value. For example, CRI90 is 10%-20% lower than CRI80 luminous flux.
6.2. Price effect
High CRI LED light sources usually require the use of higher quality materials and technologies to achieve. The cost of these materials and technologies tends to be higher, so it will lead to an increase in the overall cost of luminaires.
For example, the price of CRI95 LED light source will be 10-20% higher than the price of CRI80 LED light source. Of course, if the price is calculated into the cost of the entire luminaire, it is expected to increase by 2%-5%, which depends on the cost of other materials of the luminaire.
7. How to choose the right CRI for different applications
Different applications have different CRI requirements. Here is how to choose the right CRI for different applications
7.1. Retail lighting
In order to display the best appearance of goods and enhance the shopping experience of customers, retail stores must use CRI90 or above lighting. High CRI can more accurately present the color of the product, enhance the appeal of the product and increase your sales.
7.2. Commercial lighting
Office, shopping malls, supermarkets and other commercial lighting, usually require 80 CRI or above lighting. Such CRI values can provide enough color accuracy to meet the needs of daily work and shopping.
7.3. Residential lighting
Lighting for residential use must have luminaires of 80 CRI or above. Make sure the decorations and furniture you see are true colors. However, some high-end residential buildings may choose CRI90 or above luminaires for lighting to improve the quality and atmosphere of the living environment.
7.4. Museums and Galleries:
In order to accurately restore the original color of the artwork, museums and art galleries will choose CRI95 or above luminaires for lighting. These luminaires are able to provide a lighting effect closer to natural light, helping the audience to better appreciate and understand the artwork.
7.5. Photography and Film:
In the studio and film production site, luminaires with high CRI value are also essential, and luminaires with CRI95 or above are usually selected for lighting. They can ensure that the color of the picture is accurate and natural to meet the needs of post-production and audience viewing.
7.6. Medical place
Hospitals, clinics and other medical environments have higher requirements for CRI values of light sources. Usually, these venues will choose CRI95 or higher luminaires to ensure that doctors can accurately observe the patient’s skin color and condition, reducing the possibility of misdiagnosis.
7.7. Outdoor lighting
Outdoor lighting requires high brightness while considering energy saving, so generally choose CRI70 or CRI80 luminaires. Because the products with high CRI will reduce the luminous efficiency of the luminaires.
8. The future of color rendering
With the continuous development of lighting technology and the improvement of people’s requirements for lighting quality, the development trend of CRI also shows the following significant characteristics.
8.1. High CRI trend
In more and more application scenarios, such as commercial lighting, home lighting, museum lighting, etc., high CRI light sources are favored because they can more truly restore the color of the object. In the future, with the advancement of technology and the reduction of costs, high CRI light sources will be more popular and become the mainstream products in the market.
8.2. Full consistent spectrum
With the development of LED chips, phosphors and packaging technology, the development of high CRI products that are closest to natural light, we call it Full consistent spectrum, can let you feel the effect of indoor as in outdoor sunlight. For example, 98 CRI typical, R1-R15 >90, high Rf and Rg values
8.3. Human-Centric Lighting
Humanistic lighting focuses on the regulation of human biological rhythms, such as sleep-wake cycle and temperature regulation. At the same time, it also pays attention to emotional and mental health regulation, such as by creating a comfortable and harmonious lighting environment, which helps to relieve stress and improve mood.
8.4. CRI and intelligence:
With the development of intelligent lighting technology, CRI is combined with intelligent control. Users can adjust the CRI value of the light source according to their preferences to provide a more comfortable and personalized lighting experience.
9. Conclusion
It is necessary for you to understand the importance of CRI, the advantages and disadvantages of high CRI and how to choose CRI values for different applications in order to make the most correct lighting choice.
I hope this blog of SUNME Lighting can give you a comprehensive understanding of CRI, SUNME lighting has been committed to providing high-quality CRI luminaires, need more information, please leave your contact, we will reply you as soon as possible.
