The difference between CRI and TCLI

TCLI was developed by former BBC engineer Alan Roberts to measure the color rendering index of a light like CRI. Similar to CRI, it measures how true the color of the light is compared to the reference sample. However, TLCI is "observed" using a television camera, so this color rendering index is meaningful for a television camera. The spectral response curve used by TLCI is an average of many cameras, called a "standard camera" (indicators such as CRI use a standard observer that is the average of the human eye).

While both TLCI and CRI are indicators used to assess light quality, they have different uses and are optimized for different scenarios. CRI (Color Rendering Index) is designed for human vision and is used to evaluate the accuracy of a light source in reproducing color compared to a natural light reference. It uses eight standard color samples that don't necessarily fit the specific needs of film or broadcast. The TLCI (Television Lighting Consistency Index), on the other hand, is tailored specifically to the needs of television and film production, taking into account how the camera "sees" light. Its 24-color sample set includes skin tones and other hues that are critical to screen accuracy, making it more suitable for cinematic applications. While a high CRI score may indicate good overall color rendering by the human eye, it does not guarantee that the camera can accurately capture these colors, which is where TLCI's strength lies.

All in all, with TLCI, the staff can use real and consistent data to do the editing work in the movie/TV color without having to work with guesswork, saving time and hassle. It's a valuable tool for the companies that buy cameras and movie lights, but it's also important for the manufacturing companies that make those lights.