When using DTG printing as a decoration method, there are many additional steps that are not necessarily required for traditional decoration methods (such as screen printing). For example, many people are not aware that we must spray a liquid “pretreatment” chemical on all dark garments before they can be printed using the DTG process; this additional step is required to ensure that the white ink that is printed onto the garment does not “soak in”.
During the curing process, the pretreatment can discolor slightly, and can sometimes leave a slightly off-white residue that may be interpreted as a stain of some sort. This is entirely normal and should disappear with the first wash of the garment. When pretreatment is applied to certain light garments, the curing process will sometimes cause a light “yellowish” box to appear around the design – again, this is most often caused by normal discoloration of the pretreatment fluid on the garment, which should come off in the first wash. Aside from the possible discoloration of the pretreatment fluid itself, you may also notice a “box” around the printed design – this box is can sometimes be caused by the pressure from the heat press (used for curing the inks) forcing the fibers down into the garment.
Since we are applying high heat and heavy pressure for an extended period of time, this box will sometimes be noticeable until the garment goes through the first wash cycle. Additionally, thicker items such as fleece, and items that contain polyester will usually have a harder time masking the difference between the area that has been heat pressed and the area that has not; once again, the first wash should take it back to normal.