Why should I pretreat my garments for direct-to-garment printing?
The ink used for digital garment printing is very thin in comparison to the plastisol inks used by screen printers. When a dark garment is printed, a pass of white will be printed first to create an under-base for the color pass. If no pretreatment is applied to the garment, the printed white ink would have the same effect as milk being poured onto it.
The application of pretreatment has three purposes for the white ink. The first is to stop the white ink from just being absorbed into the garment. The second purpose is when the ink and pretreatment touch one another, a reaction occurs and causes the white ink to gel up. The gel up of the white ink preps it for printing on with color without bleeding or mixing with other colors. Once the print is completed, it is cured with a heat press. During this process, the pretreatment’s final job is to help create a strong bond between the ink and garment for good washability.