How to Make Durable DTG Prints That Look Great and Last Longer

DIRECT-TO-GARMENT PRINTING helped change the apparel decorating industry from the technology’s inception by allowing fast, multicolored garment printing in an on-demand scenario vs. traditional methods of decorating such as transfers or screen printing. This is because there is reduced setup and teardown when compared to traditional decorating methods. The softer hand and higher detail prints are incredible for certain designs that otherwise would be hard to achieve.

One of the biggest things that many decorators overlook is how to ensure that prints look great in the hands of the end consumer, even after they have washed and worn the shirt many times. The typical problem with DTG was wash durability. The prints may look great prior to any washing or wearing, but after a wash or two the print may look worn, cracked, and not as “good” as it did when it was first produced. There’s a lot as to WHY this happens. So, let’s look at a few of these issues such as why it happens and what can be done to help achieve a better, more durable print for your customers.

Several variables will affect the final prints and how they interact and build upon each other. The garment itself, the base upon which it is printed (i.e. the pretreatment itself), the inks, and final curing of the inks all contribute to the durability and quality of the final print. Are these the only factors? No, but we are going to look at how these basics interact with each other to determine what we get in the final product. And the interaction between these variables is greater than you think.

Note the gaps in the white ink film. This is an open area of the weave of the shirt and we can’t print on “thin air”.

The Artist’s Canvas: The Garment

One issue for successful DTG printing is the garment itself. My standard joke is that all DTG printers do the same exact thing; they drop ink on the surface of the shirt. The technology and how it is jetted can vary, but the end result is the same. We get a finished print. On dark shirts we print white and then the colored inks. However, the canvas on which it is jetted directly can affect the finished quality and durability of the print.

Our shirts play a big factor in how prints look. I always say that I can make any DTG printer look good. Think of your desktop printer at home. If you print a photograph on regular run-of-the-mill copy paper and then print that same photo on photo glossy paper, which one will look better? The answer is obvious. It all comes down to the paper that you printed on. Coarser shirts that are of a lower thread count, with more fibers, and looser weave structures will not print as well as a higher thread count garments with a tighter, smoother print surface. It’s the same as the copy paper vs. photo paper, just in fabric form. A shirt that has a looser weave means that there is less substance for the ink droplets being printed to adhere to, i.e. you cannot print on thin air. This is why when you sometimes remove the shirt after printing, you can see the design on the platen of the printer.

This “shirt quality” parameter has a variety of different variables that will play into the long-term durability of the print based on cotton quality (carded, combed, ring-spun, etc…), thread density, and more. A thicker thread with a vertical difference in weave structure of the threads can create “hills and valleys.” These must be filled in to create a smooth, consistent ink film when printed vs. a tighter, thinner thread that will require less ink.

The Primer

Pretreatment also is an often overlooked and undervalued component in the entire DTG process but is one of the more important factors in achieving great prints. Outside of varying qualities of the pretreatments that do contribute to how well a print will last, there are several things to consider.

For instance, how the pretreatment is applied and how it interacts with the shirt is a big component in this process. How much pressure is used to apply the pretreatment (is it surface applied or forced into the shirt fibers?); the type of nozzles used to spray the pretreatment (which varies deposit amounts, droplet size as well as consistency across the spray width); and the actual droplet sizes of the “sprayed” fluid. In addition, other factors all play into how well the pretreatment will help contribute to achieving your goals.

How these above-mentioned factors for the pretreatment interact with the garment is another different issue. Some shirts readily will absorb the pretreatment, while others will cause the pretreatment to “sit” on the fibers of the shirt. This often is due to the manufacturing process of the shirt and the chemicals used in that manufacturing process. This can affect how much pretreatment is used to achieve good results.

It’s like a balancing beam and a gymnast — striking the best shirt for the best price for the best end product. I have sprayed the exact same amount of pretreatment onto two different shirts of the same exact thread count and thread quality (let’s say 20g total of pretreatment) and one shirt looked like nothing was sprayed on it while the other shirt looked like it was soaking wet. This was because the pretreatment beaded up on the fibers and did not readily penetrate the fibers of the garment as easily as the first shirt.

Another factor is the amount of pretreatment that is applied will affect your print. You need to find the “Goldilocks Zone” for application amounts. Again, this will vary based on the quality of the pretreatment and the quality of the shirt. My general rule of thumb is that a lower-quality shirt generally will require more pretreatment than a higher-quality shirt. A lower thread count shirt will require more pretreatment than a higher thread count piece. A lighter-weight shirt needs less pretreatment than a heavier shirt. Darker shirts need more pretreatment because we are not trying to hide the darker color, i.e. black shirt vs. light grey shirt.

And again, you can spray your shirt, but you can’t bridge all the “empty spaces” of a loosely weaved shirt. This then directly affects the ink film and how much ink needs to be deposited to get a good smooth print.

Using more pretreatment on the shirts before printing generally will help fill in and cover the fibers better, leading to less pinholes in the white ink. But the more pretreatment you use, the heavier the feel of the pretreatment on the shirt. This reduces the quality of the feel of the final product, which introduces issues with discoloration interaction with the shirt, dyes, and residual chemicals left on the shirt from the manufacturing process and potentially the durability of the ink during washing. Again, there’s a balancing act going on here to ensure good prints based on these two variables — the shirt and pretreatment.

There nearly are five threads in the black shirt for every four threads in the blue shirt. Higher thread counts typically will have a tighter knit weave (black vs. royal). And small gaps in the weave itself (black vs. royal). Thicker threads will make a heavier shirt, with more highs/lows in a cross section of the fabrics.

Bringing Forth Life

Now, add the ink onto the growing list of variables. Ink is the thing that everyone sees, bringing life to our imaginations on the garments our customers wear and that we print. Achieving a balance of garment and pretreatment will factor into how much ink is needed to be applied to achieve a smooth, solid white as well as get a durable print. This is where everything starts coming together.

DTG inks have been improving significantly over the years. It generally is not an ink’s fault for “failing,” but a compilation of issues that contributes to a finished print not being durable. In aviation it is not typically one issue that causes a plane to crash. It is a combination of multiple issues that stack up. In DTG printing, this creates the inevitability of a “crash” that could have been avoided had the individual issues been dealt with appropriately as they appeared.

So, let’s talk about ink film thickness. We want as smooth, pinhole free ink film as possible for several reasons. One is, it looks better. Another is that a smooth ink surface provides less “access” points for dirt, detergents, etc., to get into the structure of the ink film and destroy the physical structure of the ink. A simplistic view is to think of potholes in the road during the winter. Water, salt, and ice get into a structural defect of the pavement or concrete. It then freezes and expands, often leading to a bigger pothole or breaking up of the pavement.

Water and detergent can do the same thing with ink films, causing expansion/contractions issues leading to premature decay of the ink film. There’s a lot more science behind how the molecular structure of ink, water, and detergents cause the swelling of ink structures, etc. than can be explained here in one article. But suffice it to say we want to achieve as smooth and consistent ink film as possible, cured correctly, to give the best, most durable print, using the minimum amount of ink necessary.

Related to the ink film thickness, we can look at this very simplistically. The most common stress on the ink film will be stretching, or tensional factors. Putting on and taking off a shirt often makes the print stressed as the shirt stretches. The stretch characteristic of the inks varies somewhat between different ink sets, but many inks have good stretchability and that attribute is improving as the inks sets evolve.

But this stretchability also is dependent upon the ink film thickness. Think of it this way: A single layer of tissue will stretch and tear much easier than several layers of tissue. A thin layer of ink will stretch to a breaking point typically sooner than a thicker ink film. You also can think of it like a single hair that, when stretched, will break more easily than multiple, thicker intertwined threads of hair.

This ink, applied onto the pretreatment that was applied onto the structure of the garment, now are all interdependent upon each other. A higher thread count shirt with a smoother printing surface may require less pretreatment (to a point, as we must have enough pretreatment to interact with the ink) and will require less ink that a thicker shirt. With more pretreatment, you possibly need more ink to fill in the weave gaps (hills and valleys). These variables interplay with each other, each one affecting the others in combination to result in the final prints.

The perfect film thickness is paramount and will be dependent on the ink set characteristics itself, the pretreatment, and amount of pretreatment applied to the shirt. Also take into consideration the structure, weave, thread count, and chemical residues in the shirt from the apparel manufacturing process.

Typically, a thicker ink layer will result in a more durable, stretch-enduring print than a thinner ink film that later may crack when stretched sooner than a thicker ink layer stretched the same amount. But, too thick of an ink film can be detrimental to causing ink curing time differences, which can be exacerbated in an on-demand print line where every shirt is different. One shirt may have a minimum white ink film while another will have a larger area with a thicker ink film, thus taking longer to cure.

The slightly heavier deposit of pretreatment and heavier white ink layer covered the fibers much better resulting in a smoother white ink film.

Baking the Cake

The curing process may seem to be apparent and easy, but it plays a huge role in how the inks interact in the long run when the end customer washes and wears the shirt. A properly cured ink film will result in a good, long-lasting print. How the customer washes and wears the shirt also will affect this outcome.

Many factors contribute to the decline of a finished print. How it is washed will contribute to the degradation of the ink film. Hot water can be more detrimental to the inks by softening the polymers up more than cold water will. Just being in the water will cause the ink film also to swell (think of the freezing of water in the winter in potholes). Detergent and the agitation of being in a washing machine with jeans and coarser fabrics will rub and cause wear-and-tear on the ink film. This is why it is often recommended to turn your shirts inside out during washing to keep the ink film from undue interaction with other apparel.

Then, throw in how the garment is dried and that it also will affect the lifespan of the garment and print. Ideally, hang drying will help extend that garment’s life exponentially. But blow torch drying at the surface temperature of the sun in a dryer that also has heavy jeans and other apparel in it will cause a further drying out of the ink and pretreatment polymers as well as wear-and-tear on the ink film. How well your print endures during this portion of the Wear-to-Wash-to-Dry cycle will depend on each of the variables during the “construction” of the finished print. Typically, a thicker ink film (to a point) will wear better than a super thin ink film.

Note the higher differentiation of the height of the peak of the thread to the valley of the weave (black tee vs. royal tee).

Take the Recipe and Bake the Cake

Once we understand how all these factors are inter-related, we can fine-tune our recipe to produce the best possible product for ourselves and our customers. Is it easy? No. Does it take some testing and patience? Yes.

This is one reason why DTF has seen success but also why it has benefits and its own set of shortcomings. The ink film on DTF is often thin because it’s printed on a smooth surface similar to ‘photocopy paper.’

This uses less ink, and the continuity of this ink film generally leaves no surface breaks or structures to allow in detergents and foreign objects. These can degrade the ink film integrity during washing and drying.

Now you add the DTF powder to the structural layer of the DTF print. This is like the pretreatment in DTG. However, this is more of a glue that is the interface between the ink film and the shirt fibers. It can more easily bridge the “weave, hills, and valleys” of the garment, but also at a price. What makes DTG softer and more detailed is harder to achieve with DTF, while DTF can be more durable in used in a wider variety of substrates.

This continuous surface structure also leaves the DTF print to have more of a feel and have less breathability on large solid areas of a shirt that can make it uncomfortable to wear. There are trade-offs between the two methods of decorating, but the basic concepts still apply to both, though the variables change slightly.

When we look at how we can achieve the best, most durable prints for our customers, it is simply more than printing ink onto a garment. It really is like baking a cake. Anyone can bake, but it doesn’t mean that you’re a master chef or the food will taste good. The ingredients can change and how the cake is baked all play a role. Understanding the ins and outs of how all these factors interrelate is key to your shop being successful in the apparel decorating market.

And know what tool in your tool chest to decorate the job at hand is essential. There is no “One Method Fits All” decorating method. Whether it is DTG, DTF, screen printing, or other decorating process, the most important thing for you is to make money. Create a great product at a fair price and become a profitable master decorator.

Remember, there are many tools available to achieve the same end image, but the best way to “bake the cake” is to manage the ingredients of the best and most desirable process so you can make the best prints available for your customer. That will help you maintain your reputation and keep customers coming back.