LED production varies from chip to chip, so manufacturers measure every package and sort it into bins by chromaticity, flux and forward voltage. Luminaire makers buy specific bins or blend them to hit a target color within a stated MacAdam ellipse. Tight bins mean better matching between fixtures, higher cost and sometimes long lead times; field mismatches often trace back to a change of bin between production runs.
Replacement fixtures came from a different binning run and they're visibly pinker, get the original bin code from the factory.
Order spare luminaires with the original job so they come from the same binning run; ordering one later almost guarantees a visible mismatch.
Also heard as
- LED binning
Related terms
MacAdam ellipse
A small oval around a target color on a chromaticity chart, inside which color shifts go unnoticed by most viewers.
SDCM
Standard Deviation of Color Matching: the step size used to state how closely light sources match in color.
Chromaticity
Where a light's color sits on a color map once brightness is set aside, given as coordinates such as x, y or u', v'.
LED
Light-Emitting Diode: a semiconductor light source, made white for lighting by coating a blue chip with phosphor.