DTG Direct to Garment Pretreatment for T-Shirt Printing

Direct to Garment (DTG) combined with pretreatment of t-shirts, in my opinion, changed the custom apparel printing industry for the better due to its compact setup and easy processes to follow. This combination works well if you appreciate a good design on your t-shirts. They would see a design with bright and lively colors, especially on dark colored ones.

What is the best DTG pretreatment for t-shirt printing? The DTG Pretreatment Non-Staining FBX-100 is the best DTG pretreat brand for t-shirt printing. It is non-staining on both dark and light colored garments which will save you a lot of headaches when pretreating.

Other benefits of this pretreatment solution brand, when compared to other brands, include: 1) saves you money because you need less of this (50% approximately), 2) easier to use for there is no shaking involved as there are no developed chunks of solids, 3) maximum white ink since it produces 33% brighter colors, 4) advanced washability, and 5) longer shelf life which is about one and a half years.

Now that we know the best pretreatment solution to use, let me discuss in detail the pretreatment process itself. This way I can explain why it revolutionized the t-shirt printing industry for the better.

What Is Pretreatment?

Pretreatment (also called pretreat for short) means using a liquid solution that is used by DTG printers. This allows the printing of white ink on dark garments and washability on colored t-shirts, especially black ones.

It also allows an underbase white ink layer to be printed under the actual design to make the colors that lay on top of that to be more vibrant. The white ink printed stays on top of the t-shirt and does not get soaked into it.

It prevents the ink changing color from white to gray and not give a smooth surface to be further printed on.

This effectively allows the design on the t-shirt to remain bright and focused, not muted and blurred. I compare this to the scenario of a primer being applied to drywall which prevents the spread of paint beneath it.

What Are the Types Of Pretreatments Used?

There are two types of pretreatment methods being used on t-shirts – light and dark.

Each has its own purpose, applicability, and requirements.

Light Pretreatments

Light pretreatment is used on any white or light-colored garments. This will result in dark colors of the design being noticeably richer in appearance.

Other benefits include a more detailed quality of design, no color bleeding, and increased resistance to fading and discoloration.

Do note that there is really no need to pretreat a white t-shirt though there is a big difference in terms of better print quality obtained for pretreated ones.

Dark Pretreatments

Dark pretreatment, on the other hand, lays the groundwork where the white ink can be printed on. It prevents this ink from staying wet and allows the color ink space to work on and not be mixed together.

The heat press activates the pretreatment solution allowing the print to mesh with the garment fibers.

Choosing whether to have a light or dark pretreatment is dependent on the color of the ink that will be utilized.

If there is a white ink present as part of the design color scheme, then you need to use dark pretreatment regardless of garment color.

Light pretreatment is not to be used with white ink and dark pretreatment on a white shirt. There is a good chance that a yellowing effect will be seen once the garment is past the heat press. Issues with wash quality will also come up later.

How Do Pretreatments On T-Shirts Work?

Pretreatment basically “flashes” the white ink to such a state that causes it to change its inherent properties.

Pretreatment changes the white ink from a liquid to a semi-liquid state which allows a smooth, printable surface to be produced. Further applied colored inks will not get mixed with this white ink underbase.

This pretreatment solution fills in the space between the weaved t-shirt fibers. It blocks the ink from soaking in these spaces thus effectively rendering the same to stay on top of the t-shirt surface.

Additional ink added will appear with greater detail when contrasted to the white backdrop.

Types Of T-Shirts That Can Be Pretreated

There are new developments on the types of garment that can be pretreated for use with a DTG printer.

Whereas before, only cotton and natural fibers can be used with digital inks and pretreatments, the same can be done with polyester up to the 100% variety. There is a pretreatment solution specially developed for this type of garment.

You may also consider the clothing and apparel companies selling pretreated shirts. This type of t-shirts allows you to work around the labor, equipment, and supplies requirements of pretreatment and go straight to the DTG printing process itself.

Pretreatment Process Do’s And Don’ts

You should apply pretreatment for all areas where the ink will be placed. Also, alternate stacking process where the wet sides are touching each other should be done for the t-shirts as you are pretreating them.

Use safety gloves, respirator, and clothes that will cover your arms for you are dealing with chemical solutions here.

It is important to use the t-shirts within 30-60 days from application of pretreatment to obtain the best results. If the t-shirts are to be stored for quite some time, dry them completely to avoid mildew.

How Is Pretreatment Applied?

Pretreatment can be applied in 2 ways – by hand spraying or through a pretreat machine.

Hand Spraying Method

This method involves the use of a sprayer. This basically involves spraying the solution on the garment evenly in a smooth back and forth motion.

The hand sprayer used for this task can be as simple as ones used in gardening spraying tasks. Or, they could be as complex manual sprayers in the market, such as the Wagner Flexio 2000 HVLP Sprayer, that is handheld, runs on AC/DC power, and has variable nozzle settings.

The amount of pretreatment needed depends on the color, t-shirt weave, and the design that is to be printed.

Remember to dilute your solution with distilled water prior to usage. Ideally, there should be a 2:1 ratio amount of pretreatment solution and distilled water.

Don’t use tap, well, or filtered water for they may have mineral contents that will affect the pretreatment solution.

There should be enough pretreatment solution sprayed on the garment or there will be an effect on how the garment looks and washes.

If there is too much pretreatment applied, dark areas may appear on the garments. And if it is too little, the prints will look dull and blurry.

For a 14” x 16” print, I usually use the following amount of pretreatment solution:

100% cotton – 13 to 15 grams
50/50 blends – 16 to 18 grams
100% poly – 18 to 20 grams

As I have mentioned earlier, by using the recommended brand, I realized a 50% reduction with the recommended volume of pretreatment solution.

Adjust the pretreatment solution amount if the print area is different.

I always do my pretreatment application in a well-ventilated area away from the printer and I use a fold-up table for this task.

Hand Spraying Application Method

I start by pre-pressing the shirt under the heat press to get out any moisture and to flatten out the surface for the pretreat to lay on.

The clothing must first be on a flat, waist-high surface facing up front. It should be flat and even on the same surface.

You should start by sprinkling nicely from left to right at the top of the t-shirt. Shift downwards from the top right and then to the left. Finally, move up to the original location.

Remember that areas to be printed upon should be the only ones where pretreatment is to be applied.

Apply the solution adequately and even making sure that there is a wet sheen on treatment areas.

You have essentially sprayed a box. Afterward, you should spray in a series of strokes vertical wise until you completely sprayed the contents of the entire box.

Use a squeegee or a roller to help spread the treatment evenly after spraying. This also flattened the fabric fibers that may have risen during the pretreatment process.

Automatic Pretreat Machine

The easier and faster method is through the use of an automatic pretreat machine. This is an enclosed device where the t-shirt is loaded into and pretreating is done by the machine at the press of a button.

You will get the same exact amount of spray and at the same spot each time. Advances such as a laser guide system (available in Cobra Pretreat Machine) and saved settings for each garment type are also available with some of these pretreat machines.

In using a pretreat machine, you have to adjust for the width of the spray pattern and amount of solution dispensed.

Also, consider that the machine needs to be cleaned and maintained each time after use to prolong its life cycle and ensure consistent performance.

Aside from its obvious advantages of being a faster method and facilitates an even treatment of the t-shirt, the amount of pretreatment solution can also be controlled.

One downside of using a pretreat machine is that it is costly for starters since you have to buy this piece of equipment. But when production is higher this may be helpful and a time saver.

There are reports received of inconsistent spraying coming from certain brands of pretreat machines even after it has been checked.

Owners, who have switched to manual sprayers, found out that they can lessen the amount of pretreatment solution needed and still get the same results. This is when compared to the amount that they are using with the pretreat machine.

Due to the fact that you don’t have to switch from a full chest print, to a half chest, or a left chest. Each requires different coverages and the time it takes to switch which format you are pretreating for.

With manual spraying you can do it on the fly, adjusting your spray length and width.

Pretreatment Drying Process

After the pretreatment solution has been applied, it is now time to dry the t-shirt. There are again 2 methods that can be utilized for this purpose.

The first method is to just hang the t-shirt somewhere to be air dried. This process will take longer but it enables extra moisture to be taken away. You can use the heat press for a couple of seconds just to make sure it is completely dry.

The second method is through using a heat press. Which is the method I recommend of course.

I will set the temperature at 330F for about 45 seconds at medium pressure and in a hover position. This position entails not fully closing the heat press leaving about an inch gap to allow steam to escape.

Other printers prefer a closed heat press method. For cotton t-shirts, the temperature is set at 380F for 15 seconds. Polyesters are set at 270F for 10 seconds.

Do not use a teflon sheet or silicone treated parchment paper when using a heat press with pretreat. Also, do not load a t-shirt on a DTG platen that is wet or has moisture on it.

You can also consider using a blow dryer or a heat tunnel when drying your pretreated garment. However, never use the tumble dryer for there may be lint remnants that will get stuck with the pretreated t-shirt.

Pre-printing Preparation

You need to pre-press the t-shirt before printing on it to make sure that there is no moisture leftover. A heat press can be used but you need to put a cover sheet on top of the t-shirt to protect it.

This preparation also flattens any fibers that may be present.

Always thread onto the platen when applying the heat press. This is to prevent moisture from blowing to the other side of the t-shirt.

DTG Printing Of Pretreated T-Shirt

After drying the t-shirt properly, it is now time to print using the DTG printer.

This process is similar to printing a t-shirt that has no underbase.

The white ink gets printed first on the pretreated t-shirt. Pretreatment allows it to sit on top of the garment.

The colors follow next and they lay on top for dark garments or any garment that needs white ink.

You may feel the ink and pretreatment when the t-shirt is worn for there is an extra layer of ink added.

Causes Of Pretreatment Stains On T-Shirts

Stains, burns, and discolorations that are noticed after the garment has come out of the heat press may be caused by too much pretreat, heat and pressure.

You should never set the temperature of the heat press above 330F degrees.

The other possible reason for these stains is that too much application of the pretreatment solution was done especially when the hand spraying method is utilized.

And another possible cause is when the heat press is left with the residue of the pretreatment solution. This will then be applied to the next t-shirt treated.

How To Get Rid Of Pretreatment Stains On T-Shirts

You should use water first when rinsing the affected garment then sponge with white vinegar and then rinse again.

Repeat the process this time using liquid detergent and then with white vinegar again. Try to get rid of as much stain as possible.

If it takes too much time to remove these pretreatment stains, just set the affected garments aside and mark them as spoiled items in your books.

Using the recommended brand mentioned earlier in this post would render these stains a non-issue.

Advantages Of Pretreated T-Shirts

Using pretreatment with a DTG printer allows a printing shop to cater to low volume but a high-quality section of the apparel market. People with a desire to have t-shirts that are custom-made, release limitedly, and possess standout design would gladly serve as the ready market.

It is theoretically possible that apparel printing shops can choose to specialize in this niche and still make money.

Disadvantages Of Pretreated T-Shirts

Pretreatment is a costly and space consuming process.

As a business owner, you have to account for the costs of spraying booths or an automatic pretreat machine, safety equipment, labor hours and space to work with.

Another relative disadvantage is the productivity level if you choose to undertake pretreating with your DTG printer. It will take the time of your staff to go over the process of sorting, applying the treatment, and drying the garments.