Color Rendering Index
A color rendering index (CRI) is a quantitative measure of the ability of a light source to reveal the colors of various objects faithfully in comparison with an ideal or natural light source. Light sources with a high CRI are desirable in color-critical applications such as neonatal care and art restoration.
What does CRI mean in lighting?
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 Selecting LED Lighting?
CRI received an average usefulness score of 3.5, compared to 3.2 for CCT, 3.1 for lamp type, and 1.9 for the brand name.
It is probably favored because of the stark difference between high CRI and low CRI lights.
LEDs with high CRI ratings will render colors accurately, which helps textures, fine details, and colors to stand out. This has a flattering effect on people, making their hair lustrous and skin look rich and healthy.
High CRI LEDs are valuable in both the home and workplace. In grocery stores, for example, fruit and vegetables will look juicier and more appetizing when displayed under high CRI lights.
In hospitals, whereas accurate color rendering is critical, and allows doctors to do their jobs safely.
Conversely, LEDs with low CRI ratings will make things appear drab and dull. Colors will not be portrayed accurately, which causes people to look unappealing and their skin to look lifeless.
It’s fair to assume that most people don’t want to look unpleasant, so high CRI LEDs are typically preferred over low CRI LEDs.
What Is The Good Number of CRI?
As a general rule of thumb, you should aim for a minimum CRI of 80. Though the closer to 100, the better. CRI is measured on a numeric scale of 1 to 100, so a score of 100 indicates that light is displaying colors exactly how they would appear in natural daylight.
CRI scores in the 90s are exceptional. They show colors almost as accurately as daylight, and any slight discrepancies will not be noticeable to the human eye. A CRI of 90 or higher is recommended for hospitals, museums, print studios, and retail shops.
Scores of 80 are also acceptable and may be useful in places that require softer or more ambient lighting. As CRI drops below 70, color inaccuracies will become more evident to the human eye.
Low CRI bulbs aren’t entirely invaluable, however. They may be beneficial when a gloomy effect is desirable, such as on movie sets or at horror attractions.
In some situations, minimum CRIs are mandated by law. In California, for instance, Title 24 states that LED lights in residential buildings must have a minimum CRI of 90, and in particular, a minimum R9 value of 50.
