CRI stands for Color Rendering Index, which is a quantitative measure of a light sources ability to reproduce the colors of objects faithfully in comparison with an ideal or natural light source. In general terms, CRI is a measure of a light sources ability to show object colors "realistically" or "naturally" compared to a familiar reference source, either incandescent light or sunlight. CRI is calculated from the differences in the chromaticities of eight CIE standard color samples when illuminated by a light source and by a reference illuminant of the same correlated color temperature (CCT), commonly measured in kelvins, indicating the light color produced by a radiating black body at a certain temperature. The smaller the average difference in chromaticities, the higher the CRI. A CRI of 100 represents the maximum possible value. Lower CRI values indicate that some colors appear unnatural.
CRI is important in LED lighting because it measures the ability of a light source to reveal colors of objects in contrast to a natural light source, such as the sun filtering in through your windows. When it comes to choosing the right light bulbs for your home, CRI for lighting plays a role. Colors should be crisp and everything should look sharp so that your décor, paint colors, furniture (and reflections) look their best. Good color rendering is key for photography, retail store displays, grocery store lighting, art shows, and galleries, just to name a few. For most indoor and commercial lighting applications, 80 CRI is the general baseline for acceptable color rendering. A CRI of 90 or higher is recommended for applications where color accuracy is critical, such as art galleries, museums, retail outlets, hospitality, and medical buildings.
