WHAT IS GOOD CRI?
The color rendering index (CRI) is measured as a number between 0 and 100. At zero (0), all colors look the same. A CRI of 100 shows the true colors of the object. Incandescent and halogen light sources have a CRI of 100.
Typically, light sources with a CRI of 80 to 90 are regarded as good and those with a CRI of 90+ are excellent! The general rule is: The higher the CRI, the better the color rendering capacity.
CRI is independent of color temperature. These are two different things. For example, a 5000K (daylight color temperature) fluorescent light source could have a CRI of 75, but another 5000K fluorescent light source can have a CRI of 90.
This chart is a good depiction of differing CRIs, with each image having the same warm color temperature (2700K):
WHY IS CRI IMPORTANT?
When designing any space, color, texture, and finishes play a critical role in the process. Equally important is lighting. With high-CRI lighting, colors pop, textures stand out, and finishes have depth and luster. Think of lighting as the fourth element of good design, which turns colors and textures into a vibrant palette of finishes and materials.
What is CRI? Color rendering index (CRI) is a measure of how accurately a light source displays colors. CRI is measured on a scale from 1 to 100, with 100 representing daylight. CRI was devised by the International Commission on Illumination (CIE) to evaluate how effectively light sources represent color across 8 colors, from R1 to R8.
CRI is determined by comparing the appearance of a colored object under an artificial light source to its appearance under an incandescent light at 100 CRI. The higher the CRI, the better the artificial light source is at rendering colors accurately. The lower the CRI value, the more unnatural colors appear when illuminated by the light source.
Equally important to finishes and hues are how people look in the space. High CRI values, particularly in R13 and R9 values, produce natural skin tones with more depth. A CRI value of 80+ will effectively portray colors and finishes. When the most accurate color rendering is essential, 90+ CRI values are recommended.
COLOR RENDERING TOOL:CRI
The most familiar calculator is CRI (Color Rendering Index), which has been utilized to measure color rendering properties of light sources for over 50 years. CRI has been widely adopted in the lighting industry for its ease of use as it only calculates a single metric―Fidelity (Ra). Sunlight has a CRI of 100, the highest mark on the 0-100 scale. CRI is calculated using an average of 8 specific R-values representing 8 different colors within the light spectrum. The R-values measure the concentrations of 14 colors within a light source’s emitted spectrum and the ability to render individual colors. High R9, R13 and R14 values are particularly important for illuminating skin tones, decorative art and retail merchandise properly. Our products are engineered specifically to deliver high R9, R13 and R14 values to assure your installations deliver superior color rendering.
THE NEXT GENERATION OF COLOR RENDERING
IES TM-30-15 is a new color rendering system that remedies flaws/limitations of CRI, providing complementary and more detailed information that benefits both specifiers and manufacturers. The much wider range of colors is a more accurate reflection of the real world – allowing you to show detailed colors for skin tones, wood grains, decorative art, furnishings, merchandising and more.
While CRI isn’t going anywhere soon, it’s important to familiarize yourself with the new TM-30 metrics as they will become more common in years to come.
A combination of TM-30’s Fidelity (Rf), Gamut (Rg) and Color Vector Graphic will help further clarify beyond the typical CRI metric how a test source compares to a reference source.