A strip advertised as CRI 95+, R9>90, full spectrum still doesn't tell you what light it actually produces. Every meaningful color and biological metric — CRI and R9, TM-30 Rf/Rg, CCT and Duv, melanopic EDI and DER — is computed from one thing: the spectral power distribution. If the SPD isn't published, every claim on the datasheet is an assertion you can't verify.
Yuji Lux publishes measured spectral reports
Yuji Lux product pages carry measured spectral reports and photometric reports for the strips in the range — including the dynamic families where spectrum changes with the setting: SunWave™ (daylight-oriented tunable white), Tunable White, and Dim-to-FlameWarm™ (3000K→1800K). Spectral engineering is the company's core capability — from phosphor formulation to finished strip — so publishing the resulting spectra is the natural way to let specifiers verify the claims.
What you can do with a published SPD
Verify color metrics. Recompute CRI, R9 and TM-30 instead of trusting a single marketing number — our CRI Comparison Tool shows why two sources with identical Ra can render reds completely differently, computed live from real SPDs.
Compute melanopic quantities. Melanopic EDI and DER (CIE S 026) come straight from the spectrum — essential for circadian specifications and WELL v2 work. The measurement chain is explained in our melanopic EDI explainer, and our own office field measurements show why the spectrum, not the lux number, decides the biological result.
Explore before you specify. The Spectrum Designer lets you mix LED die and phosphor spectra and watch CCT, Duv and CRI R1–R14 update live — the same spectral logic behind the products.
What to ask any vendor for
| Item | Good practice |
|---|---|
| SPD data | Measured curve per CCT variant (not one generic graph), ideally at 5 nm or finer |
| Measurement conditions | Drive current, temperature, integrating-sphere test conditions stated |
| Derived metrics | CRI with R9 (not Ra alone), TM-30 Rf/Rg, CCT and Duv per variant |
| Consistency | Binning tolerance (SDCM) — a beautiful SPD means little if batches vary |
Frequently Asked Questions
Why isn't CRI enough without the spectrum?
CRI (Ra) averages eight pastel color samples and hides the deep-red R9 region and spectral gaps. Two strips with the same Ra can have visibly different rendering and very different melanopic content — differences the SPD shows immediately.
Does Yuji Lux publish spectral data for its LED strips?
Yes. Product pages include measured spectral reports alongside photometric reports and specification sheets, including for the tunable and dim-to-warm families where the spectrum changes with the setting.
What can I calculate from an SPD?
CCT and Duv, CRI including R1–R14, TM-30 Rf/Rg, and the CIE S 026 melanopic quantities (melanopic EDI and DER) — every specification-relevant number for both visual and circadian design.
Can Yuji Lux engineer a custom spectrum?
Yes — custom spectral engineering from target metrics (melanopic DER, CRI/R9, CCT/Duv) through phosphor-level design to production is a core capability. The delivered spectrum ships with its measured data.