White ink keeps bleeding on 100% poly — how do you stop dye migration?

Question

Printing whites on red/royal performance polys and getting pink/blue ghosting a day later? That's dye migration, and it's one of the most frustrating problems in the shop. Here's what actually helps.

What's happening: polyester dye sublimates (turns to gas) under heat and migrates up into your ink film. The dryer and even a flash can trigger it, and it often shows up hours after the print looks fine.

What works, roughly in order of impact:

Use a low-bleed / poly white or a dye-blocking underbase. These are specifically formulated to resist migration. This is the single biggest lever — a standard white on hot poly will lose.
Cure low and slow, not hot and fast. Lower dryer temps (as low as the ink's cure spec allows) reduce how much dye gasses off. Blasting heat makes it worse.
Print a blocker/barrier gray or a heavier underbase between the fabric and your colors.
Test the actual garment. Migration varies by dye lot and color — reds and royals are the usual offenders. Print a sample, then let it sit 24 hours before you judge it.

Don't judge a poly print the minute it comes off the dryer. Migration is a slow ghost — give it a day.

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Kontraktr Team · Accepted Answer

All correct. The one habit that saves the most reprints: treat every new poly as guilty until proven innocent. Print a small test, set it aside overnight, and check it the next morning before you commit the run.

Also worth knowing — sublimated (all-over dye) polyester and cheap fashion polys are the worst offenders, and the migration risk rises with cure temperature. So a low-bleed white plus the lowest cure temp your ink allows is the combo that wins. If a customer insists on a bright color on a hot poly with no low-bleed ink, that's a conversation to have before you quote it, not after.