Glossary → Dye migration
Dye migration.
heat reactivating a garment's own dye so it bleeds into the print
Heat from curing or pressing reactivates the polyester dye in the garment, which then bleeds up into the ink on top, most visibly turning a white print pink. It is also called sublimation bleed, and it belongs to the blank as much as to the ink: polyester and poly blends do it, cotton does not. It can appear hours or days after the piece leaves the line, which is how it gets past in-line QC and into a customer's hands.