This issue may be due to dye migration. This happens most frequently on red T-shirts, with the white ink gradually going pink over 1-2 weeks post printing.

Dye migration usually occurs with lower-quality T-shirts, especially those made with subpar dyes; in this case, the dyes may be described as migratory, bleeding or fugitive. An alternative cause is when coloured T-shirts from a previous season are dumped in the black dye vat during production, so what you’ve bought as a black T-shirt was quite different in an earlier life. Dye migration is often exacerbated with synthetic fibres but can also affect cotton T-shirts, particularly those with dyes in the yellow, orange, red, magenta or purple part of the spectrum. Dye migration can also be exacerbated by too much heat during curing.

Even then, the migration issue can often take weeks to manifest and most print shops and indeed print jobs do not have/allow the luxury of test printing 2-3 weeks before the required delivery date.

Dye migration typically occurs if dyes have not been properly fixed or are of lower quality, making them more prone to bleeding.

If you find that a batch of T-shirts is prone to bleeding, we recommend returning them and cancelling the job.

Some printers absolutely refuse to use supplied T-shirts. Other printers may accept supplied T-shirts but, in the event of dye migration problems occurring, will only supply a free reprint but stipulate that they will not replace nor cover the cost of replacing the faulty T-shirts.

However, if you DO decide to proceed with printing supplied T-shirts that have demonstrated dye migration problems, then you’ll need to use a bleed blocker to prevent or slow down the migration of the fugitive dye. Typically, these blockers contain activated carbon (charcoal) with a high absorption capacity. Due to their carbon content, they are usually grey, which can be less than ideal for design purposes and will require at least one additional screen and, for multicoloured designs, a second screen for a white underbase over the grey bleed blocker. This will significantly increase the overall cost of the job and will often end up costing more than if a good quality, migration or bleed resistant dye had been used in the first place. Cheap shirt, expensive print job.

We believe that it is worth having this conversation with your customer rather than them getting all the benefit of the lower price of the T-shirt and you wearing the higher cost and greater risk of printing. In a reciprocal relationship, risk, cost and benefits should be shared more equally.

In summary, the dye migration that you may encounter is due to the fabric, not the ink. We advise testing T-shirts before starting a production run, as noted on our tubs (noting the 2-3 week caveat noted above), and consider returning the rogue shirts to the supplier for other shirts that are guaranteed not to have migrating dye issues.