Sometimes, if a screen printed custom t-shirt has not been properly cured, the shirt will begin to “bleed” after washing it, causing the printed design to fade. So that wonderful white design on your rad red shirt might end up a dull imperfect pink after putting it through the wash. This is a phenomenon known as “dye migration.”
Dye Migration it’s likely to occur when applying plastisol ink to a synthetic garment like polyester. What’s happening is the shirt’s dye is mixing with the print’s ink as a result of the heat treatment process. The issue stems from the fact that the temperature at which polyester releases its dye happens to occur before the ink can fully cure. The heat causes the dye to sublimate, converting it into a gas, which then seeps into the ink. This will eventually cause the ink to “bleed,” dulling the color of the ink.
In order to avoid this disaster, we use certain “low-bleed” inks that contain ingredients that block the dye from mixing with the ink, as well as lowering the required temperature to cure. Since screen printing often needs an underbase, we can also use a special underbase that can shield the plastisol ink from the shirt’s dye.
Dark or bright colored garments like red, blue, and black are most susceptible to dye migration, but there is an easy way out if the ink is darker than the material it’s printed on. If, say, a black design is printed on a white t-shirt, dye migration may still occur in this case, but, since the ink is so dark, the light-colored dye seeping into the dark ink won’t be noticeable!
To avoid the possibility of dye migration altogether, you can either print on 100% cotton shirts or choose to use Heat Transfer Vinyl to apply your design to a polyester garment.