How to Better Understand and Choose the Color Rendering of Your Lighting?

27 février 2025

Initiated by the International Commission on Illumination (CIE) in 1948, the study of color rendering has continued to evolve. Originally, this research was conducted to characterize fluorescent lighting and discharge lamps used in public spaces. The CRI (or Color Rendering Index, also called Ra) measures how well a light source can display colors accurately. This index assesses how well a lamp allows us to distinguish all colors. The CRI ranges from 0 to 100. The lower the index, the less distinct the colors. On the other hand, the higher the CRI, the better the color rendering. As a reference, daylight has a CRI of 100.

Below, a table explaining color rendering. We can see that as CRI decreases, color nuances become less visible.

Most compact fluorescent and LED bulbs have a CRI around 80. But how can we understand CRI ratings?

For compact fluorescent lamps: The CRI is often indicated by a three-digit code that combines CRI and color temperature. In this code, only the first digit relates to CRI. For instance, compact fluorescent lamps with excellent color rendering have codes like 930, 940, or 950.
For LED lamps: Most LED bulbs available in stores have a CRI between 75 and 85, providing satisfactory and pleasant light quality. However, in the architectural and technical lighting market, CRI can go as high as 98. Indeed, a CRI above 90 offers excellent light quality and color rendering.

To illustrate, look at the difference between these two light spectrums. With a CRI of 85, you’ll see numerous color nuances that are unfortunately much less visible with a fixture at CRI 50.

How to Adapt Your Fixture’s CRI to Your Interior Spaces?

In general, a CRI between 80 and 90 provides good color rendering. Therefore, choose fixtures with this CRI for common spaces like your living room, dining room, or bedroom. Lighting with a CRI from 70 to 80 is ideal for hallways or entryways. Finally, lamps with a CRI between 60 and 70 are suited to garages, basements, or attics. Choosing a light fixture with a CRI appropriate for its function is essential.
In public places such as offices, shopping centers, hotels, restaurants, or kitchens, a CRI of at least 90 is recommended. These spaces require excellent color rendering to perform various tasks in optimal conditions.

Comment mieux comprendre et bien choisir le rendu de couleurs de vos luminaires ?

As previously mentioned, color rendering quality should be high in public spaces! Certain tasks require precision, and a high CRI is essential for offices as well as hair salons or beauty studios. Choose fixtures with a CRI above 90.

Similarly, to cook under ideal conditions, choose lighting based on its CRI. In the kitchen, to achieve good color rendering, select a fixture with a CRI of at least 80. Anything below 80 may not provide sufficient color quality!

In the living areas of your home, such as the living room, dining room, or bedroom, it’s important to have good color rendering. For dining, displaying your décor (photos, paintings, etc.), or other needs, your fixture’s CRI should be between 80 and 90. Below 80, color rendering will be insufficient, and color nuances will not be as visible.

Opinions vary greatly between warm and cool colors in bathrooms! However, do not confuse the color temperature of your fixtures with their color rendering index. For bathrooms and quality color rendering, as with other living spaces, we recommend a CRI between 80 and 90. Don’t confuse warmth with color!

A Few Final Important Points:

When labeled “Standard,” a fixture’s CRI is typically low.
An LED lamp with CRI=80 may provide more pleasant light than a compact fluorescent bulb with the same CRI.
Do not confuse CRI with color temperature (measured in kelvins)! Although related, they are different concepts. A lamp labeled “daylight” may not necessarily render all colors well.
A low CRI does not mean all colors are poorly rendered. Some colors may appear undefined (such as certain blue tones), while others are well-defined.
Two lamps with the same CRI do not necessarily have the same color rendering weaknesses.
CRI does not improve by using two mediocre lamps instead of one.