Color rendering index: a key factor to consider when choosing your lighting
Picking the right lighting for every room and every application comes down to three factors: light quantity, light color and the color rendering index. While light quantity (lumens and lux) has a direct influence on people's well-being and performance, light color (Kelvin) contributes to creating a certain atmosphere and affects our state of mind. The color rendering index (CRI) is a measure of how accurately objects and surfaces are illuminated by the light source.
The Color Rendering Index (CRI) ranges from 0 to 100. At 0, all colors look the same, while lighting with a CRI of 100 shows true colors, just like sunlight. In other words, the higher the CRI, the better the light source reveals true colors:
We’ve all been there before: you’re trying on a new outfit or a brand-new pair of shoes and before you make the final call, you ask the shop assistant whether you can go outside for a second to ‘see what the color looks like in real life’. It may seem like an odd request, but it actually makes more sense than you may think. After all, sunlight renders colors perfectly, which is why the lighting industry has agreed to give sunlight a color rendering index of 100.
The sun is a unique light source because it contains all colors. That is why we are able to see every single color outside. Unfortunately, creating the same experience using LED lighting is simply impossible, as it requires adding lots of colors to the light spectrum. Everything from red to green and from blue to white, as well as every combination and blend you can imagine. The most difficult light color to reproduce is red, and yet red has a big influence on CRI values!
The first LED lighting introduced to the market had a CRI of 70-80. This lighting would make people look drab and tired, regardless of the light color. Since then, however, the technology has evolved. And while a CRI of 100 may not be possible, more and more LED fixtures now have a CRI well into the 90s. High-CRI lighting is becoming more and more popular in the workplace and at home, so you can be sure that the fabric or wallpaper you picked out in the shop will look just as good at home.
The CIE 13.3-1995 standard describes how to calculate CRI values exactly. Basically, the procedure comes down to comparing eight reference colors under a certain light source with the same colors under daylight. Next, you calculate the distance between each reference color and the ‘true color’. The closer the match, the better and higher the CRI of the light source.
The CRI scale is divided in steps of ten and values are accompanied by a "greater than" (>) sign by default. The unit of the CRI value is Ra. Tronix Lighting recommends using light sources with a CRI of at least >80 Ra.
The optimal CRI value varies from one application to the next. A printing company, for instance, will demand more accurate color rendering than a consumer looking to buy outdoor lighting. In shops, showrooms and galleries, playing with CRI values can also be an interesting option. Choosing a light source that renders a lot of white, for example, will highlight all white materials, objects and surfaces in the room, making them seen even more fresh and bright. An LED chip with lots of warm colors, on the other hand, emphasises earthy tones, while slightly more blue would accentuate the water in a pool.
To get the lighting conditions just right in every room and for every application, it is important to match the CRI, light color and light quantity, as all three factors influence each other. It is also worth noting that LED lighting with a higher CRI will always be less energy efficient.
On top of CRI values, the Black Body Radiation (BBR) or Black Body Locus (BBL) also affects how we experience colors. Both terms come from the world of physics and refer to a surface that absorbs all radiant energy that reaches it. These surfaces appear black because they absorb light instead of reflecting it.
For 100% true color rendering, both the CRI value and the BBR/BBL value have to be in the right spectrum. The lighting specialists at Tronix Lighting are true experts in the matter. What’s more, Tronix Lighting has an extensive range of LED lighting solutions with excellent and true-to-life CRI values and high energy efficiency. From LED panels to LED downlights, LED high bays and LED line lights.
Want to learn more about our solutions? Visit our showroom in Uden or contact our lighting specialists by sending an email to sales@tronixlighting.com
- Value 100-90: excellent, true-to-life color rendering
- Value 90-80: good, color rendering is relatively accurate.
- Value 60-80: moderate, the colors shown may not be true.
- Value <60: poor, the colors shown are not true to life.
Most accurate color rendering
We’ve all been there before: you’re trying on a new outfit or a brand-new pair of shoes and before you make the final call, you ask the shop assistant whether you can go outside for a second to ‘see what the color looks like in real life’. It may seem like an odd request, but it actually makes more sense than you may think. After all, sunlight renders colors perfectly, which is why the lighting industry has agreed to give sunlight a color rendering index of 100.
The sun is a unique light source because it contains all colors. That is why we are able to see every single color outside. Unfortunately, creating the same experience using LED lighting is simply impossible, as it requires adding lots of colors to the light spectrum. Everything from red to green and from blue to white, as well as every combination and blend you can imagine. The most difficult light color to reproduce is red, and yet red has a big influence on CRI values!
Increasingly higher CRI values
The first LED lighting introduced to the market had a CRI of 70-80. This lighting would make people look drab and tired, regardless of the light color. Since then, however, the technology has evolved. And while a CRI of 100 may not be possible, more and more LED fixtures now have a CRI well into the 90s. High-CRI lighting is becoming more and more popular in the workplace and at home, so you can be sure that the fabric or wallpaper you picked out in the shop will look just as good at home.
Minimum >80 Ra
The CIE 13.3-1995 standard describes how to calculate CRI values exactly. Basically, the procedure comes down to comparing eight reference colors under a certain light source with the same colors under daylight. Next, you calculate the distance between each reference color and the ‘true color’. The closer the match, the better and higher the CRI of the light source.
The CRI scale is divided in steps of ten and values are accompanied by a "greater than" (>) sign by default. The unit of the CRI value is Ra. Tronix Lighting recommends using light sources with a CRI of at least >80 Ra.
Playing with CRI values
The optimal CRI value varies from one application to the next. A printing company, for instance, will demand more accurate color rendering than a consumer looking to buy outdoor lighting. In shops, showrooms and galleries, playing with CRI values can also be an interesting option. Choosing a light source that renders a lot of white, for example, will highlight all white materials, objects and surfaces in the room, making them seen even more fresh and bright. An LED chip with lots of warm colors, on the other hand, emphasises earthy tones, while slightly more blue would accentuate the water in a pool.
A complicated spider’s web
To get the lighting conditions just right in every room and for every application, it is important to match the CRI, light color and light quantity, as all three factors influence each other. It is also worth noting that LED lighting with a higher CRI will always be less energy efficient.
Black Body Locus
On top of CRI values, the Black Body Radiation (BBR) or Black Body Locus (BBL) also affects how we experience colors. Both terms come from the world of physics and refer to a surface that absorbs all radiant energy that reaches it. These surfaces appear black because they absorb light instead of reflecting it.
For 100% true color rendering, both the CRI value and the BBR/BBL value have to be in the right spectrum. The lighting specialists at Tronix Lighting are true experts in the matter. What’s more, Tronix Lighting has an extensive range of LED lighting solutions with excellent and true-to-life CRI values and high energy efficiency. From LED panels to LED downlights, LED high bays and LED line lights.
Want to learn more about our solutions? Visit our showroom in Uden or contact our lighting specialists by sending an email to sales@tronixlighting.com
Overview
