You’ve probably seen it before: The white ink on your red jersey starts to get a pink tinge. Or the camo print on a shirt bleeds through the white lettering. The culprit? Dye migration – when color from a polyester or polyester-blend garment bleeds into ink, changing its color. It’s a tricky issue for apparel decorators, particularly because, experts say, the migration might not show up for days, weeks or even months after a job is printed, packed and shipped.

From left, Mark Bailey of SanMar, Rick Roth of Mirror Image, Rob Coleman of Nazdar and Bruce Basen of SAATI Print discuss dye migration during a Shop Talk at Impressions Expo Atlantic City.

“Dye migration is kind of like the hidden killer,” said Rob Coleman, vice president at ink supplier Nazdar SourceOne. “It’s like cholesterol.”

Coleman was speaking at Impressions Expo in Atlantic City last week, during a Shop Talk session from the Ink Kitchen, hosted by Rick Roth, an award-winning screen printer and president of Pawtucket, RI-based Mirror Image Inc. Mark Bailey, senior manager of decorator and digital solutions at Top 40 supplier SanMar (asi/84863), and Bruce Basen, technical sales representative for screen printing supply maker SAATI Print, also shared their expertise during the session. Consider their tips to help prevent the issue.

1. Use low-temperature inks and dye blockers.

Using inks that cure at low temperatures and have bleed-resistant properties can help prevent dye migration. You may also have to use a dye blocker as a base to create a barrier between the shirt and your ink. For instance, if you’re printing white lettering on top of a digital camo shirt, you should use a black bleed blocker as an under base, then flash cure it, then print the white and other colors of the design, Basen said. That will help keep the white ink from getting a gray tinge.

Just beware of assuming you’ll find a one-size-fits-all ink solution to dye migration, Roth said. “That’s wishful thinking,” he added.

Dye migration isn’t only a screen-printing problem. It can happen with any decorating technique that requires heat to cure, including heat transfers and dye sublimation. If you’re decorating a dark-colored polyester garment with a heat transfer, consider using a transfer with a charcoal backing to inhibit color bleeding.

2. Work with higher-quality products.

Bailey of SanMar suggested promotional products distributors and apparel decorators encourage their clients to choose a better product, that has bleed-resistant qualities, to help minimize dye migration. Polyester garments colored with cationic dye (like SanMar’s PosiCharge products) tend to have better color fastness and are less prone to bleeding.

“Finding a better fabric that’s cationic will cost more, but in the end it costs less” because decorators will have a shorter setup time and run into fewer issues, Bailey said. “You get what you pay for.”

Another option is to use silicone inks, rather than plastisol, since silicone doesn’t contain the plasticizer that’s the “root cause” of dye migration on polyester, Coleman said. This highly elastic ink also has a low cure temperature, but they’re more expensive than plastisol ink. But it has no “matt-down properties” so it’s not a good fit for rough or high-nap fabrics. “It works great on smooth polyester,” Coleman said.

Roth recommends silicone ink for decorating a high-end garment, like a $250 jacket, for example.

3. Test, test and test some more.

It’s almost always a good idea to do a dye migration test on a polyester or blend fabric before you start a print run, particularly if it’s a brand, color or style you haven’t worked with in the past. There are even times where styles from the same supplier will react differently to decoration, if they’ve been dyed in a different facility, so Roth and the other experts recommend doing a dye migration test if, for example, a tee you’ve worked with in the past has a new country of origin on the tag.

“If you’re printing thousands of garments, it’s crazy not to do the test,” Roth said.

To do a dye migration test, place your dark polyester fabric on a warmed-up heat press, add a few drops of plasticizer (such as a non-curable reducer), then layer a 100% white cotton scrap on top. Set the press for 320 degrees for 30 to 35 seconds, then look at the white fabric. The more stained the white fabric, the more of an issue dye migration will be. “If you see just a little bit of color, you’re probably OK,” Roth said.

Bailey also recommended consulting the spec sheet for every garment style you’re working with to determine the optimal conditions for decorating.

The other area to test is your dryers – using test strips, probes and a pyrometer – to make sure there are no hot spots along the belt. “The temperature on your dryer is not the temperature,” Roth said. “There’s no real substitute for doing a lot of testing.”

4. Don’t cut corners on curing.

Even though too much heat is the culprit behind dye migration, that doesn’t mean you can skip the all-important curing process. Low-temperature inks are no exception. “You always need to cure the ink through and through,” Basen said.

Bailey compared curing a T-shirt to cooking a slab of meat: “A lot of decorators think they can run the dryer hotter and faster [to save time]. It’s like steak. You have to have constant curing. Longer and lower is better if you can.”

And don’t pack shirts into boxes right after they leave the dryer. Shake them out before stacking to release heat; a stack of garments that’s too hot can also trigger dye migration.

5. Educate your customer.

When possible, try to steer your customers toward garments and colors that are less prone to dye migration. Or change up the design to accommodate the chosen garment – consider using a pink dye from the start on a red shirt, rather than trying to print white, for example. Clients don’t know what they don’t know, so it’s up to the decorator or distributor to share their own expertise on the topic.

“A lot of things are solved by customer service and art, instead of finding a technical solution,” Roth said.