In many ways, the pre-treating step is the most important step of Direct-to-Garment (DTG) printing. Pre-treat is a solution comprised of a mix of distilled water and what is essentially glue. It is applied to a garment and then heat cured to remove the moisture. The pre-treat provides a solid, printable surface for the DTG printer to lay ink on. Properly pre-treating a garment will ensure a quality print that will be durable and have excellent washability. With that in mind, let us examine the pre-treating process.
An automatic pre-treat spraying machine or by hand are the two ways in which a garment may be pretreated for DTG printing. Since pre-treat must be laid evenly over the garment, an automatic spraying machine will obviously produce the most consistent results. However, with practice, spraying by hand will work just fine if an automatic sprayer is out of your price range.
The amount of pre-treat needed to ensure a high quality print is dependent on the weight and color of the garment being printed. For lighter garments, you will use less pre-treat. On the other hand, you will need more pre-treat for darker garments. This is because darker colors are more likely to show through the ink in a design, so more pretreat will ensure that the design is opaque enough to cover the shirt’s color. There are also different types of pre-treat that will allow you to print colors on white garments, and onto polyester garments or blends. It is very important to know which type of pre-treat is needed, and how much, for each type of garment and color to ensure the highest quality finished product.
Once the pre-treat has been sprayed onto the garment, the garment must be cured using a heat press. A pre-treated garment is cured by being pressed with 60-80 pounds of pressure for around 35 seconds at 355 degrees. The temperature of the press is crucial, but is determined based on the type of pre-treat being used. This step is vital for the durability of the print, as any remaining moisture can interfere with the ink’s ability to adhere to the garment.
As with any part of the printing process, there are several common hiccups associated with the pre-treating process. One is staining, which is typically caused by impure water used in the manufacturing process of the garment itself. Garments are manufactured all over the world and the water used in dying the product is not always the same quality. Another common issue is scorching the garment, which will leave a burn mark from the heat press. Certain garments are not able to handle the time, temperature, and pressure necessary to create a proper, printable surface. Speaking of pressure, it is also possible for the heat press to leave a permanent box on the garment. It is important to do a lot of test printing onto different brands and types of garments to see what works best. Some brands simply pretreat and print better than others due to where the garments were manufactured. With a little research, and practice, most of these issues can be avoided.
Without a solid printable surface, a DTG printer is useless. It is the pre-treating step that will turn a garment into a printable product, and ultimately a sellable one. The key to a beautiful, durable print is to fully understand the pre-treating process and to perfect it. Once you have that in order, the printer will do the rest of the work.
