Beyond CRI: why modern lighting quality demands TM‑30—and the critical role of R9
In architectural lighting, color accuracy is no longer a luxury—it is a design imperative. As LED technology rapidly evolves, so too must the metrics we use to evaluate light quality. For decades, the Color Rendering Index (CRI) served as the industry’s go‑to standard. But today’s LED‑driven environments require a more sophisticated, more reliable approach.
This article explores the latest insights on CRI, how it compares with the TM‑30 color rendition method, and why the R9 value has become indispensable in high‑end architectural, hospitality, retail, and art‑driven spaces.
1. The limitations of traditional CRI in modern LED lighting
CRI (Ra) measures how well a light source reproduces colors compared with a reference source, using only eight pastel color samples. Designed decades ago for incandescent and discharge lamps, CRI often fails to capture the behavior of modern LED spectra.
Recent analyses in 2025–2026 highlight several key issues:
- LEDs with the same CRI rating can render colors very differently because CRI ignores saturated hues like deep red.
- High‑CRI LEDs (95+) are increasingly required for premium architectural and hospitality applications, yet CRI alone does not guarantee color quality.
- The global demand for superior color fidelity—in art galleries, retail, and residential environments—is fueling the shift beyond CRI.
CRI remains useful as an introductory metric, but it is no longer sufficient for specifying truly high‑performance lighting systems.
2. Why R9 is critical for high‑quality architectural lighting
If CRI is the headline number, R9 is the story behind it. R9 represents the accuracy of deep, saturated red, one of the most challenging colors for LEDs to reproduce.
Why R9 matters
Industry research shows that even light sources with high CRI values can perform poorly in red reproduction—a critical flaw in many environments.
A high R9 value is essential for:
- Skin tones in hospitality, offices, healthcare, and beauty environments.
- Food presentation in restaurants and retail. [hi-hyperlite.com]
- Brand and textile accuracy in fashion and luxury retail.
- Artwork and pigment fidelity in museums and galleries.
What counts as a good R9?
- R9 > 50 = good
- R9 > 80 = excellent
- R9 > 90 = exceptional, but difficult to achieve with modern LED spectra due to red‑region sensitivity.
Put simply: if accurate reds matter—and they almost always do—R9 must be part of every lighting specification.
3. TM‑30: the new global benchmark for color rendering
Today’s lighting professionals increasingly rely on TM‑30, the advanced color rendition method developed by the Illuminating Engineering Society (IES). It was created specifically to address the limitations of CRI.
TM‑30 provides:
- Rf (Fidelity Index) – a robust equivalent to CRI, but calculated from 99 color samples instead of 8.
- Rg (Gamut Index) – a measure of color saturation (values >100 indicate increased saturation, <100 reduced).
- Hue‑specific analysis – pinpointing exactly how a light source shifts color across 16 hue bins.
The U.S. Department of Energy emphasizes that TM‑30‑24 is now the most accurate and comprehensive standard for evaluating LED color rendition.
Furthermore, new industry documents like ANSI/IES LP‑30 (2026) guide designers in applying TM‑30 effectively throughout the entire lighting design process.
4. CRI vs. TM‑30: what designers need to know
Color Accuracy
- CRI evaluates 8 pastel samples.
- TM‑30 evaluates 99 color samples, giving designers a far more reliable view of real‑world color performance.
Red Performance
- CRI ignores deep reds unless the extended scale is used (R9–R15).
- TM‑30 inherently integrates red fidelity across multiple hue bins.
Saturation & Hue
- CRI provides no information on saturation.
- TM‑30’s Rg index and hue-shift graphics show exactly how colors are altered by a light source.
Suitability for LEDs
- CRI was never designed for LED spectral patterns.
- TM‑30 was built specifically for modern solid‑state lighting.
In high‑end architectural environments—where materials, finishes, colors, and natural elements must appear exactly as intended—TM‑30 gives designers the precision they need.
5. How R9 and TM‑30 complement each other
While TM‑30 provides the most holistic understanding of color rendition, R9 remains a critical “quick check” for red fidelity, especially in environments where reds define visual quality:
- Retail (textiles, brands, packaging)
- Hospitality (fabrics, décor, food)
- Workplace (skin tones, natural appearance)
- Art and museum lighting (pigments, warm hues)
TM‑30 describes red performance across multiple hue bins, but R9 offers a simple, singular indicator of whether a luminaire can render one of the most visually sensitive colors.
For specifiers, the best practice is clear:
Specify TM‑30 (Rf + Rg) together with minimum R9 performance targets.
6. What this means for kreon projects
At kreon, we believe lighting should express “purity of light, proportion, and geometry.” Achieving that purity means ensuring colors are rendered with the fidelity intended by the architect or interior designer.
By integrating TM‑30 metrics and paying close attention to R9 in our product development and project guidance, we help ensure:
- Materials appear natural and authentic.
- Textures reveal their true character.
- Spaces feel warm, human, and sophisticated.
- Art, objects, and food are presented with full vibrancy.
In a world moving beyond CRI, precise color rendition is not a feature—it's a foundation.
Conclusion
Lighting quality today requires more than a single number.
- CRI remains a starting point.
- R9 is essential for authentic red reproduction.
- TM‑30 is the new gold standard for evaluating and specifying color rendering.
For designers working with premium materials, curated interiors, and human‑centric environments, embracing TM‑30 and R9 ensures that spaces look—and feel—exactly as envisioned.
If you’d like a kreon lighting expert to help evaluate your project’s color‑rendering requirements or specify fixtures with high TM‑30 and R9 performance, we’re here to help.