I'm confused about pre-treatment sprays. What's the rule for when to (and when not to) use it?
This question has gotten more complicated to answer in the past two years, as different types of pre-treatment have been introduced. But the basic answer is still the same: white or light, 100 percent cotton shirts canbe printed without pre-treatment; any shirt printed with white ink—whether as a color or as an under base for printing darks—needs to be pre-treated.
Pre-treatment’s function is to keep the ink bound to the top of the shirt. In the case of white, this provides a bright under base layer. Without the pre-treat, white ink will sink into the shirt, rather than stay on top. Without a bright under base layer, the color layer will be muddy and the shirt will be unsellable.
Use light polyester pre-treatment on 50/50 poly/cotton blends and 100 percent polyester. Generally, polyester pre-treatment only needs a light coat. Use polyester pre-treatment only on white and light colored goods.
For an in-depth look at pre-treating for D2 printing, click here.