CRI, or Color Rendering Index, helps compare how a light source renders object colors. It is useful when visitors need to judge fabric, cosmetics, printed samples or finishes. It is one selection measure, not a guarantee of correct brand colors or a more valuable-looking product.
What the number means
The usual general CRI, Ra, averages the results for eight standardized color samples compared with a reference light source of the same correlated color temperature. Its upper value is 100; negative values are possible. CRI 90 is an index score, not 90% accuracy against daylight. The reference is not always natural daylight, and a score of 100 does not guarantee perfect rendering of every product.
CRI 90+ can be a useful screening criterion for color-sensitive displays. CRI 80 may serve other tasks. Neither is a universal exhibition minimum. Two lamps with the same Ra can still render a particular material differently; do not infer an exact Pantone match, print sharpness or buyer response from the number.
Look beyond the average
R9 evaluates a saturated red sample and is not included in the eight-sample Ra average. Ask for it when red products or related shades matter. If available, TM-30 data adds color-fidelity information (Rf), gamut information (Rg) and more detailed color-shift graphics. These measures describe different aspects; they are not interchangeable CRI scores.
CCT in kelvin describes the warm or cool appearance of white light. It does not indicate CRI or brightness. Compare candidate lamps at the intended CCT and a similar light level on the product. There is no single best neutral-white range for every booth.
Ask for the right evidence
Request a colorimetric or spectral test report identifying the exact fixture, light setting and test conditions. Confirm the reported Ra and relevant additional values. A report for one switchable-CCT setting does not establish every setting's result. An LM-79 report can provide relevant optical and electrical measurements; check what the actual report includes. An IES light-distribution file alone does not establish CRI. LM-80 concerns maintenance of LED source output characteristics, rather than proof of a finished fixture's CRI. Safety markings such as UL or ETL, or a CE mark, do not by themselves establish a CRI value.
Test the display you will use
Compare real fabrics, printed brand-color samples and finishes under the proposed lamps, then in the expected hall light. Check reflections, shadows and glare as well as color. If photography is part of the task, test the actual camera and settings too; visual CRI is not a camera-color guarantee.
Record the chosen model, CCT, measured values and approved sample. Compare model-specific data in our arm-light range, alongside output, distribution and mounting. High CRI does not ensure enough light or even coverage.