What a CRI label leaves unanswered
A quotation stating “CRI 90” may be using Ra as shorthand. Ask whether the value is a minimum, a typical value or a claim for only one configuration. Keep the CCT and product reference with the data. Do not apply one variant’s report to an entire strip family.
| Question | Why Ra alone does not answer it |
|---|---|
| How is saturated red rendered? | R9 is outside the eight-sample Ra average |
| Will this timber finish look right? | The actual spectrum and material affect the result |
| Does the 4000K version equal the 3000K version? | The quoted data must identify the configuration |
| Will the source look greenish? | White-point tint is a different property |
Use the metric for the material
For a wardrobe, include red fabrics, navy and black garments, skin-tone accessories and the actual wood finish in a visual review. For a merchandise display, include difficult product colours rather than only white packaging. This does not measure R9; it identifies whether the proposed appearance meets the project brief.
Where colour presentation is important, request a more complete colour-rendering report if available, with the method named. Additional metrics should answer a defined question, not be presented as an unexplained collection of acronyms.
Write a checkable request
Specify the minimum Ra or R9 required by the project, the exact configuration, and the supporting document needed. If the value is unavailable, leave it unresolved rather than estimating it from a neighbouring model. A report should identify the tested sample and conditions.
Does CRI 95 guarantee perfect colour? No average metric is a promise that every object colour appears unchanged.
Can a 2700K light have good rendering? Yes; warm appearance and rendering are separate properties. Judge the relevant configuration.
