Photometric tool
LED Spectrum Simulator

Adjust correlated colour temperature, colour rendering tier and drive current to see how the spectral power distribution, chromaticity point and colour rendering indices respond — computed from the CIE 1931 colour-matching functions in your browser.

Controls

4000 K
2700 K (warm) → 7600 K (cool)
350 mA
Higher current broadens each emission band (junction temperature)
StandardRa 65–86
HighRa 72–91
PremiumRa 78–93
Phosphor blend — red share and cyan-gap depth. Range shown is across the full CCT slider.

Result — live

CCT
4000 K
Duv
0.000
CRI (Ra)
85
R9
70
x, y
0.380, 0.380
Efficacy proxy
—

Spectral power distribution — 380–780 nm

Simulated SPD Black-body reference Cyan gap

CIE 1931 chromaticity

Planckian locus Your setting

Colour rendering indices — R1–R15

Ra is the mean of R1–R8. R9 (saturated red) is excluded from Ra but is the usual bottleneck for warm-white LEDs. R12 (saturated blue) is where the cyan gap shows up.
Method. The simulator composes a white-LED spectrum from a blue pump around 452 nm plus a broad phosphor band with an optional red-phosphor contribution, and applies the cyan-gap notch near 483 nm that is characteristic of phosphor-converted white LEDs. The phosphor/blue ratio is solved so the resulting spectrum hits the requested CCT. Colour matching uses the CIE 1931 2° standard observer; CCT and Duv are obtained against the Planckian locus, and CRI follows CIE 13.3 (reference illuminant: Planckian below 5000 K, CIE daylight at or above, with von Kries chromatic adaptation and CIE 1964 W*U*V* colour differences). Values are indicative design figures for comparison, not type-test measurements.
QUEENDOM CIE-based simulation. Modelled with CIE 1931 2° colour-matching functions and CIE 13.3 colour-rendering indices — simulated model output, not type-test measurements. Figures are for design comparison; request a type test for guaranteed values.