When you hear us talk about Pretreatment, it is a liquid solution we use for our digital print process and it preserves the printing and washability of white ink within your artwork.
The concept is simple. Just as drywall is primed with primer before painting, this primer allows the colored paint to stay on top of the drywall and not soak in. If the paint soaks into the drywall, the color selected will be muted and off color (bleed).
The same is true with pretreating any shirt for digital printing. The pretreatment acts just like the primer in the drywall example. It allows the white ink printed through the DTG printer to adhere to and sit on top of the shirt. If the white ink soaked into the shirt, it wouldn’t be white – more of a grey, and not give a smooth surface for the CMYK inks to print on, resulting in a really bad looking, unsellable shirt.
Pretreatment also reacts with the white ink. This reaction is similar to when a screen printer uses a “flash” unit to semi-cure the plastisol ink so the next colors printed on top don’t smear or mix together (a result of printing wet-on-wet). The pretreatment “flashes” the white ink causing it to change properties and become more or less a semi-solid surface so when you print CMYK on top of the white ink, it doesn’t mix and look muddy.
If you need more information, have additional questions or just can't find the answer to your question here, please submit a support ticket and one of our account managers will be happy to help.