All you need to know about CRI (Color Rendering Index)
What is CRI?
CRI or Color Rendering Index is a measurement of how well an artificial light source is able to reproduce colors. The index measures how colors look under various types of lights and compares it with colors in daylight to assign it a value on a scale of 1 to 100, with a value closer to 100 being better.
Sunlight is used as the standard for measuring color rendering as colors are visible in their truest form in natural light. So a light with a CRI of 100 should be able to display colors as well as it would appear in sunlight, while a light with a CRI of 80 will reproduce the colors around 80% close to how it actually looks.
The general CRI ratings are measured using 8 standard colors with low color saturation. A light source with a high CRI will be able to accurately represent each of these colors, and therefore all other colors. An update to the colors used for measurement added 7 more colors of various intensities to this list, creating a measurement chart of 15 colors. General CRI is however the index still used most often, and an extended CRI is used only in relevant applications.
What is the use of CRI?
The Color Rendering Index is very useful in a lot of industries where accurate color replication matters. In museums and galleries, for example, lights with high CRI values will allow the colors to be clearly visible. A high CRI also allows fashion retailers to ensure that the colors on the apparel are correctly seen, reducing the chances of confusion. This is also applicable for cosmetics, where an exact match of color is required, and a change in how the product appears in daylight will influence customer decisions. The extended CRI ratings are also beneficial to the cosmetics industry. A light with a high CRI and better reproduction of R13 and R15 values (which represent skin tones), will allow variations in skin tones and shades to be seen clearly here. High CRI rated lamps also help grocery stores and supermarkets to keep their produce looking fresh and crisp, while lights with a good R9 (deep red) rendering allow the color of meat to stand out. Hospitals, clinics and others in the healthcare institutions also make use of high CRI lighting to ensure accuracy in diagnosis, as a poor color rendering can affect the skin tone and color of the person, and may lead to a misdiagnosis.
Is a high CRI rating always required?
A high CRI light is not required in every industry or space. In a parking space or a warehouse, how the color is seen will not make a big impact. Similarly, some types of office spaces can work well with mid rated light sources, while in some others, a lamp with a rating of 90 would be recommended. Residential lighting in the Philippines typically uses high CRI lights in areas where a person would get dressed, allowing them to see the colors on their clothes and makeup accurately. Along with vanities, closets and bathrooms, kitchens can also make use of high rated lights to allow the color of the food to be seen clearly.
While a high CRI is not needed in many spaces, it is vital that the light used is still rated above 80 for indoor applications to avoid confusion and ensure safety. This is why architectural and interior lighting designers in Philippines prefer to use lights with a rating of 90 or above for most task oriented areas as it offers the best color rendering.