CRI 97+

Overview

"CRI 97+" is not a standalone device or a manufacturer, but a specification for light sources: it indicates that a luminaire achieves a Color Rendering Index (CRI) of at least 97. The CRI describes how faithfully a light renders the colors of an illuminated object compared to a reference light source. The scale ranges from 0 to 100; the maximum value of 100 represents rendering that matches the reference (e.g., daylight).

In film and TV lighting, a CRI of approximately 95 and above is considered a professional minimum requirement. The "97+" designation therefore marks the upper, color-critical class and is used as a selling point for high-quality LED fixtures (e.g., series like Yuji CRI-MAX or devices like the Godox RS60Bi with CRI 97/TLCI 98).

How the Value is Determined

The standard CRI (referred to as Ra) is the arithmetic mean of the values for eight defined reference color samples (R1 to R8). These eight samples are rather pastel and do not cover highly saturated colors. Therefore, supplementary samples R9 to R15 are reported separately.

• Ra (R1-R8): Average value, usually stated as the "CRI" number.
• R9 (saturated red): Particularly important for film, as a low R9 value can make skin tones appear dull and lifeless. A high Ra value does not guarantee a high R9 value.

The CRI was defined by the CIE (International Commission on Illumination); the standardized method was adopted in 1974.

Limitations of the Metric

The CRI evaluates color rendering based on human perception, not on the spectral sensitivity of camera sensors. A luminaire can have a high CRI and still appear problematic on camera, for example, because spectral peaks (typical for some LED and fluorescent sources) are not captured by the CRI. Furthermore, the eight standard samples are not considered representative below approximately 5000 K. For these reasons, many cinematographers use supplementary metrics.

• TLCI (Television Lighting Consistency Index) models the response of a camera sensor rather than the eye.
• SSI (Spectral Similarity Index) and TM-30 evaluate the spectrum more directly or with more color samples.

Use on Set

The "CRI 97+" designation serves as a quick selection and comparison criterion when purchasing lighting and when mixing different fixtures. For color-critical applications (skin tones, costumes, set design, product shots), the highest possible CRI is preferred. Important in practice: Read the "97+" number solely as the Ra average and also pay attention to R9 as well as TLCI/SSI, as these better represent color accuracy for camera.