About: Dye lot

A dye lot is a record taken during the dyeing of yarn to identify yarn that received its coloration in the same vat at the same time. Yarn manufacturers assign each lot a unique identification number and stamp it on the label before shipping. Slight differences in temperature, dyeing time, and other factors can result in different shades of the same color between different dye lots of otherwise identical production. Although the component elements of a dye lot number are of interest only for internal business recordkeeping, retail yarn consumers have an interest in ensuring that they purchase a given color of yarn from identical dye lots.