A color rendering index (CRI) quantifies a light source’s ability to faithfully reveal the colors of objects compared to a natural light source, such as sunlight. A specialized tool, often implemented as software, determines this value by comparing the spectral distribution of the light source against a reference illuminant. For example, a light source with a CRI of 90 renders colors more accurately than a light source with a CRI of 70.
Accurate color rendering is crucial in various applications, from art galleries and retail spaces where color fidelity influences purchasing decisions to medical settings where accurate color perception is essential for diagnosis. Historically, evaluating light sources relied on subjective visual assessments. The development of a standardized, quantifiable metric provided a more objective method for comparison and specification, ultimately leading to improved lighting design and quality.