Dye lot

A dye lot is every yard of fabric or every finished garment dyed together in one vat run under one formula. Even a Pantone-matched, tightly documented recipe shifts lot to lot because fiber moisture content, water mineral levels, and how full the machine was loaded all change how much dye the fiber actually takes up. Mills running controlled QC can hold a lot's shade within a fraction of a Delta-E unit of the target; blanks pulled from general warehouse stock skip that tightest tier and drift more.

Order 500 Sport Grey tees for a school fundraiser today and reorder 200 more in three months, and the second batch can read visibly lighter, darker, or with a different heather grain — not a defect, just a new dye lot. That's why cartons and poly-bagged cases carry lot numbers on the label: so a buyer chasing a color match can ask specifically for stock from the original run.

For any print job with a hard color-match requirement — a full-front design across 2,000 units for one event — buy all the blanks in a single purchase from one lot rather than splitting the order across dates. When a true reorder is unavoidable, ask the supplier for the lot number on hand and request the closest available match instead of just reordering by color name.

A color name reads like a guarantee, but it isn't one. Two shirts labeled Black from different manufacturers, or even the same manufacturer six months apart, aren't guaranteed identical, and the difference often only shows up once the pieces sit side by side under the same light.