Binning

No two LED chips come off the production line identical. Even on the same wafer, there's natural variation in color temperature, brightness, and forward voltage. Binning is the quality control process of measuring each chip and sorting it into groups (bins) with similar characteristics.

Tighter bins mean smaller variation — a 3-step SDCM (Standard Deviation of Color Matching) bin is practically indistinguishable to the human eye, while a 7-step bin can show noticeable color differences between two "identical" bulbs. Premium LED brands bin tightly; budget brands use wider bins to reduce waste.

This is why buying three "2700K" bulbs from a no-name brand might give you one that looks warm, one that looks neutral, and one with a greenish tint. They're all technically within spec — just from different bins. When consistency matters (like a row of recessed lights or matching pendants over a kitchen island), buy the same brand, same model, same batch.