A tunable white or single-CCT part number is only half the story: what the luminaire actually delivers depends on the spectral power distribution behind the rated numbers. This simulator composes a phosphor-converted white-LED spectrum in the browser and shows, in real time, how the SPD, the CIE 1931 chromaticity point and the colour rendering indices respond to correlated colour temperature, colour rendering tier and drive current.
How to use it
Correlated colour temperature sets the target point on the Planckian locus; the phosphor/blue ratio is solved so the composed spectrum lands on it. Drive current broadens every emission band the way a rising junction temperature does, which is why high-current settings show a softer blue peak. Colour rendering tier changes the phosphor blend: a deeper cyan gap with a thinner red tail models a standard blend, while the premium tier fills the 483 nm notch the way a dual-phosphor blend does.
Reading the result
Duv is the signed distance from the Planckian locus in CIE 1960 — the tint that remains after the colour temperature is matched. Ra is the mean of R1–R8; R9 (saturated red) is excluded from Ra but is the usual bottleneck for warm white, and R12 (saturated blue) is where the cyan gap shows up first. Watch R12 fall as the tier drops: that is the notch doing its work.
Related reading
- Tunable White SPD — the two-spectrum problem behind tunable white
- Optical Reports — the parent library
- Horticulture PPFD Mapping — the plant-side counterpart