The Color Rendering Index (CRI) is a measure that evaluates how accurately a light source displays colors compared to natural light. It is expressed on a scale from 0 to 100, with higher values indicating better color accuracy. A light source with a CRI of 100 perfectly replicates colors as they would appear in daylight, while lower values may distort colors. CRI is important in various settings, such as art studios, retail spaces, and photography, where true color representation is crucial. Different types of lighting, like LEDs or fluorescent bulbs, can have varying CRI ratings, affecting how colors are perceived in those environments.