When doing direct-to-garment (DTG) printing on dark garments an essential step is pre-treating. A “dark garment” basically means any shirt that is not white. This roughly equates to anytime you have to use white ink. By pre-treating your shirt, the DTG print will have vibrant colors, bold whites and the design will last longer on the t-shirt. The ability for a print to stay on a shirt is also referred to as wash fastness.
Conversely, if a dark garment is not pre-treated the print will look faded, worn out and will quickly start flaking away in the wash. This is due to DTG being water-based. The pre-treat allows the DTG ink to sit up on the garment instead of being absorbed, which is the tendency of all water-based inks. When there are “issues” with the final print not coming out as desired, the root of the problem is almost always a pre-treat issue.
Since pre-treating is vital to DTG, it is important to apply the right amount. The following are considerations when determining how much solution to apply:
- A good starting point is 1.4 – 1.6 grams per linear inch (based on a width of 16 inches). For example, if you are applying pre-treat to a 16” wide x 20” long area, the amount of applied pre-treat will be 28 – 32 grams for an average weight garment.
- Heavier garments require more pre-treat solution and lighter garments require less. The weight of the garment itself and its construction is, perhaps, the most important variable to consider.
- It is preferable to use a high quality, ring-spun garment, with a tight-knit weave.
Many DTG printers do not know the how much pre-treat they are applying. Luckily, there is an easy way to measure how much pre-treat you should apply to a t shirt. It helps to use a pre-treat sprayer like the Zoom-AE for consistency, but there are also other methods.
This video shows you how to apply the right amount of pretreat to help perfect your DTG print. It demonstrates the necessary steps of:
- Setting up your gram scale and zeroing out the weight.
- Spraying your garment and re-weighing it.
- How to save money while testing.