CRI
CRI and colour rendering: why CRI 90+ belongs in a premium interior
CRI (Ra) describes how faithfully a light source renders colours compared to a reference. For demanding interiors, consider CRI 90+ and check R9 separately; this is design advice, not a universal standard requirement.
CRI, usually reported as Ra, compares test-colour rendering with a defined reference of similar CCT. It describes average fidelity, rather than overall lighting quality or a universal interior requirement.
Ra is the average of the eight special colour rendering indices R1–R8. Two LEDs with the same CRI 90 can therefore look quite different in practice — the average hides weak samples. The biggest mismatch appears in saturated colours: wood, leather, red wine, skin.
R9 describes saturated-red rendering and is excluded from Ra. Check Ra and R9 for the selected source; neither follows from price or a premium label.
TM-30 provides several measures and graphics, including fidelity Rf and average gamut change Rg. It is more than two indices and does not set universal quality thresholds. In 2025 CIE recommended adopting CIE Rf and reporting Ra and Rf together during the transition.
CRI is independent of CCT. A 2700 K LED can be CRI 95 or CRI 80 — two separate specs. Always read the datasheet, not the marketing label.
Practical applications
Residential
Higher colour fidelity can be a design target for the materials and use. Compare specific sources using Ra, R9 and available Rf/TM-30 data, and assess samples. Ra 90 or 95 alone does not guarantee relief, a warm impression or colours identical to another setting.
Retail & Showroom
Higher colour fidelity can be a design target for the materials and use. Compare specific sources using Ra, R9 and available Rf/TM-30 data, and assess samples. Ra 90 or 95 alone does not guarantee relief, a warm impression or colours identical to another setting.
Hospitality
Higher colour fidelity can be a design target for the materials and use. Compare specific sources using Ra, R9 and available Rf/TM-30 data, and assess samples. Ra 90 or 95 alone does not guarantee relief, a warm impression or colours identical to another setting.
Galleries & studios
For artwork and colour-critical tasks, set criteria for the actual task and materials. Higher Ra or Rf may be a design target; Ra ≥ 95 is not a universal requirement for every gallery or photographic studio.
Offices
Check EN 12464-1 for the specific visual task. Consider CRI ≥ 90 for reception areas and meeting rooms as design advice.
Advantages
- More faithful colour rendition of materials and skin
- Higher Ra alone does not guarantee identical appearance under daylight and electric light
- Assess saturated colours using additional data and samples
- Check photographic and video suitability with the actual camera as well
Limitations
- Higher CRI usually means slightly lower efficacy (lm/W)
- Same CRI does not mean the same look — also check R9 and TM-30
- CRI says nothing about flicker, glare or circadian effect
Recommendations
- Residential and Hospitality: design recommendation Ra 90, recommended 95, R9 ≥ 50
- Retail, Showroom, Fine dining, gallery: Ra ≥ 95 and R9 ≥ 80
- Always require datasheets with R9 and TM-30 values
- Do not mix luminaires with very different CRI in the same room
- Check LED strip CRI as strictly as spotlights — that is where quality usually drops
Common mistakes
- Cheap CRI 80 LED strip above the dining table
- Mixing luminaires with different CRI in the same room
- Trusting marketing claims of 'high CRI' without a number
- Ignoring R9
- Checking CRI but not flicker or CCT consistency
In summary
Ra is one measure of colour fidelity, not an overall lighting-quality score. Values of 90 or 95 can be task-specific design targets. Request R9 and available Rf/TM-30 data, and assess material samples.
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Sources
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