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Pretreatment is just as important to DTG printing as screens are to screen printing. If your garment is not pretreated correctly, your prints will not be as good as they could be. Depending on the particular pretreat you're using and the garment you're pretreating, you can usually look to fall in the range of 20 to 30 grams of pretreat for dark garments. Specific pretreatment will have specific recommendations so make sure to check with the manufacturer. I find landing in the 22-25 grams realm for both Dupont and Firebird pretreat works really well.
When do you know you have too much? The shirt will feel very stiff, even like a sheet of plastic. You'll also see the pretreatment has crystalized and stained the garment a darker shade or even a yellowish tint.
What about when you put too little on a garment? Look for the fibers! Pretreat does mainly two things. The first is that it provides a layer of treated material for white DTG ink to grab onto and build up so additional CMYK can be printed on top. The second is that it holds down the fibers. If you have too little pretreatment you will see a lot of fibers sticking through the print and they will probably look like white hairs coming through the CMYK printed areas of the design. For black shirts specifically, the white ink will look a slight blue. You'll also notice the ink will be sinking into the garment as it dries instead of staying on top.
Heavier materials like sweatshirts and hoodies? The rule of thumb here is the heavier the material, the more pretreat you need. Unfortunately, this is something that needs to be experimented with in your shop. To start, you can usually put 50% more than you do with regular shirts and based on that first test, go from there.
What about Polyblends and light shirts prone to staining/dye migration? To help fight this, you can change your pretreat and final curing process. For instance, when using Dupont pretreatment, you will cure it at 340 for 40-45 seconds. With lighter shirts, you can instead heat press it for 20 seconds, release the pressure and then press for another 20 seconds. For the final curing process, either putting the garment down a conveyor dryer or hovering longer on the heat press and pressing for a shorter amount of time are both ways to help with dye migration and polyblends.
Do you have to pretreat white garments? It's not required to pretreat white garments, but it will help the design stand out much more and last longer through washes. You will want to use a specific pretreatment marked to be used for white and light garments when not printing white ink.
Pretreatment is something that you will want to experiment with and make sure to note your results. At first glance it can seem daunting, but just like when dialing in your exposure times for screens, you'll dial in pretreat and it will become second nature.
When do you know you have too much? The shirt will feel very stiff, even like a sheet of plastic. You'll also see the pretreatment has crystalized and stained the garment a darker shade or even a yellowish tint.
What about when you put too little on a garment? Look for the fibers! Pretreat does mainly two things. The first is that it provides a layer of treated material for white DTG ink to grab onto and build up so additional CMYK can be printed on top. The second is that it holds down the fibers. If you have too little pretreatment you will see a lot of fibers sticking through the print and they will probably look like white hairs coming through the CMYK printed areas of the design. For black shirts specifically, the white ink will look a slight blue. You'll also notice the ink will be sinking into the garment as it dries instead of staying on top.
Heavier materials like sweatshirts and hoodies? The rule of thumb here is the heavier the material, the more pretreat you need. Unfortunately, this is something that needs to be experimented with in your shop. To start, you can usually put 50% more than you do with regular shirts and based on that first test, go from there.
What about Polyblends and light shirts prone to staining/dye migration? To help fight this, you can change your pretreat and final curing process. For instance, when using Dupont pretreatment, you will cure it at 340 for 40-45 seconds. With lighter shirts, you can instead heat press it for 20 seconds, release the pressure and then press for another 20 seconds. For the final curing process, either putting the garment down a conveyor dryer or hovering longer on the heat press and pressing for a shorter amount of time are both ways to help with dye migration and polyblends.
Do you have to pretreat white garments? It's not required to pretreat white garments, but it will help the design stand out much more and last longer through washes. You will want to use a specific pretreatment marked to be used for white and light garments when not printing white ink.
Pretreatment is something that you will want to experiment with and make sure to note your results. At first glance it can seem daunting, but just like when dialing in your exposure times for screens, you'll dial in pretreat and it will become second nature.
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