By Melissa Donovan
Part 1 of 2
Print service providers (PSPs) considering adding direct to garment (DTG) printing need to understand it isn’t as simple as throwing a shirt on a platen and hitting print. Certain considerations should be taken into account, like whether to use pretreatment and how to apply it.
The type of material printed to or the color of the garment dictate either pretreatment is required. It can be applied manually or with a device. Automated application via a machine is preferred due to the level of consistency from both a repeatability aspect as well as maintaining the same amount of pretreatment across the entire garment.
Pretreat Importance
Pretreatment is arguably one of the most important parts of DTG printing. During the pretreatment process, a garment is immersed or spray with a solution prior to printing. Using it ensures a vivid print that stands up to multiple washes.
Brian Walker, founder/CEO, i-Group Technologies, defines pretreatment as one of the foundations of DTG. “Incorrect pretreatment causes 80 percent of the issues in DTG printing. This is why it is so important to correctly apply the pretreatment and in the right amounts. Failure to do so will result in bad prints, poor wash durability, and make DTG printing a major headache.”
“Pretreatment is the first step or starting line to having success with DTG printing. If you start out not fully understanding the process then you are not setting yourself up for success,” agrees Brad Berger, product manager digital textiles, ink and supplies, Nazdar SourceOne.
Similarly, Luke Ryerkerk, CEO, Polyprint USA, categorizes pretreat as one of the four pillars for DTG—shirt, printer, artwork, and pretreat. He also says pretreat and curing are the top two educational and support needs for new users of DTG.
“Pretreating is vital to quality DTG shirts. It is the base from which all your DTG success builds from. A properly pretreated shirt is an essential factor that ensures your final DTG print will have bright, vibrant colors and superior washfastness,” concurs Taylor Landesman, VP, Lawson Screen & Digital Products.
Choosing the correct combination of ink and pretreatment is essential to achieving a quality finished product. According to Eric Beyeler, marketing manager, Artistri Digital Inks, DuPont, the pretreatment and ink combined impact both the color density of the printed fabric and the durability—crock and wash fastness.
As DTG printer technology advanced, the pretreatment process did as well. “The printers evolved to become robust, production-oriented equipment, so the performance demand on pretreatment increased. Consistency, range of garment styles/colors, throughput, and ease of application are key factors,” notes Shawn Liu, director of digital technologies, FIREBIRD Ink and CheaterTee.
Issues in pretreatment chemistry were once prevalent. “There were challenges with the discoloration of the garment, adding a stiff hand feel, and it came with an unpleasant odor. While some customers would accept a garment knowing that they must wash before use, this made DTG garments unsuitable for retail environments. Advances in chemistry have addressed these issues,” shares Tim Check, senior product manager, professional imaging, Epson.
“In recent years, advancements in pretreat chemicals resulted in brighter, more solid whites, and reduced chances of staining. Also, some products have made it easier to pretreat by reducing the sensitivity to applying too much or too little,” explains Paul Crocker, VP of marketing, DTG Connection.
There is constant research and development, according to Corey Mathis, digital technical services supervisor, Nazdar SourceOne, and different types of pretreatments are being tested and developed every day. Noting that a simple change in dilution ratio effects color and washability.
Why Pretreat?
There are a few reasons why a garment should incorporate pretreatment prior to it undergoing printing.
Printing a garment with white ink is one scenario. “The pretreatment is the bonding agent between the white ink and the garment. The white ink bonds with the garment better to give the base needed to print CMYK on top. Instead of soaking into the garment it actually allows the ink to sit on top, giving the print vibrancy and washability,” advises Berger.
“You cannot print a dark shirt using white ink without pretreating the garment. Light garments do not technically need to be pretreated to get a good print, however, more print shops choose to use a light garment pretreat, which results in brighter, more vibrant prints as well as improved washfastness,” adds Crocker.
While Walker is also adamant that printing white ink onto any garment means you have to pretreat, he admits that pretreating when just printing CMYK to white or light shirts can help improve image quality, brightness, clarity, and wash durability.
“When printing without white ink, it’s not critical to use a light garment pretreat, but if you do, the colors will be more vibrant, the blacks richer, everything sharper in print, and the colors more accurate due to the inks not bleeding. Even though it’s not critical, it is definitely beneficial,” agrees Jerid Hill, DTG product manager, ColDesi.
Polyester garments are another reason to use a pretreatment. “Results will vary from garment to garment, but recently some pretreatments have proven to be able to print on a dark polyester garment using white ink. There remain limitations and more work needs to be done to simplify this process,” says Crocker.
There is a specific pretreat for 100 percent dark polyester, according to Ryerkerk, but while it works most are not retail-ready, but this is something currently being improved.
How to Pretreat
A few different methods are used to pretreat a garment—dedicated machines offline, inline on the printer, or by hand.
“Pretreating can be done a myriad of ways successfully, but some methods of application are better than others for repeatability and improved throughput,” shares Walker.
For all methods, Haziel Mitchell, director of sales and marketing, Ricoh DTG, a division of Ricoh Printing Systems America, Inc., believes it is important to know how to apply the pretreatment as well as apply the correct amount. “Too little, your images will not stay or show vibrant colors. Too much and you end up ruining your shirt.”
Berger encourages PSPs to use a dedicated pretreatment machine offline from a DTG printer. “These machines help dial in the right amount of pretreatment needed to be successful and evenly spray in the print area.”
Walker also recommends utilizing a machine of some type to conduct pretreatment. “It will usually make the application more consistent from a repeatability aspect as well as how much pretreatment is applied to the garment.”
Berger cautions against applying pretreatment by hand spraying. “You could miss areas, leave streaks, and not apply the recommended amount of pretreat to the garment that can show up in the print. Garments usually need a certain amount of grams of pretreatment sprayed on to give you quality prints and washability. Too much or too little can cause quality issues and longevity of the print.”
“While some people can pretreat by hand well, when pretreating by hand, you really do not know how much pretreatment is applied each time,” adds Walker.
Additionally, there is the issue of overspray when pretreating with a hand sprayer. “With any spray system, the liquid becomes airborne and can spread across a room and into the space where an operator breathes. It is highly recommended to use an enclosed pretreatment machine as it keeps the pretreatment mist contained within and not contaminate the room,” explains Check.
Many will pretreat by hand when starting out, but they tend to move toward purchasing equipment as there are too many inconsistencies with this method, notes Hill. However, it is valuable to have the knowledge of how to manually pretreat in case the machine goes down.
“If you do start out applying pretreat by hand, understand that once you make the jump to a pretreat machine, your quality will improve. You will also spend less money on pretreat as pretreating by hand typically applies more than you need,” advises Landesman.
As an example, Ryerkerk says he has only placed DTG machines in two shops that did not purchase a pretreatment machine with their printer or within 90 days. “One of the two purchased at the six-month period and the second at the year mark. Both agreed that adding the pretreatment machine was the best business decision they made after purchasing their DTG printer.”
An alternative is utilizing inline pretreatment, which is something Kornit Digital offers, but is used on an industrial level. “It is a one-step process, eliminating the need for external process steps, enabling the best results with high retail quality,” shares Sharon Donovich, customer marketing manager, Kornit.
A fourth innovation related to pretreatment evolved from a partnership between FIREBIRD and Miele, full-immersion pretreatment. The FIREBIRD Industrial Process (FIP) implements washer-extractors to fully immerse the pretreatment onto the garment. Each blank is fully saturated, then the system removes all the excess pretreatment—any of the extra is recovered and filtered for the next batch. The blank is then place on a rotary dryer to cure. FIP processes 144 blanks in less than an hour, involving less than five minutes of manual handling.
The Cost of Pretreat
When calculating the cost of DTG printing, it’s important to include the expense of pretreatment. This includes the actual price of the consumable as well as the labor it takes to complete this part of the process.
“Print shops should always factor in the cost of pretreating. The fluid itself will run about $40 to $50 per gallon, and from product to product it varies how much pretreatment is required,” explains Crocker.
According to Berger, 30 grams of pretreatment costs around 30 cents, which is minimal to what ink costs. “So if you have to put more pretreat down on a garment to help save on ink than it is worth the saving of the ink.”
More than the price of the actual product, also consider the cost of labor involved. “Many small shops disregard this but time is money—even if the owner is doing it. You have to figure in the time from grabbing the shirt, setting up to spray, spraying the shirt, then drying the the pretreatment,” says Walker.
“After a garment is pretreated, it needs to dry prior to printing, which is typically done with a heat press. If you don’t have more than one heat press available, then it slows down your productivity quite a bit. A solid business who is looking at growth will pass that cost onto the consumer,” recommends Hill.
Words to End On
Beyond what was discussed above, we asked vendors about any other important thoughts regarding pretreatment for DTG printing.
It’s important to note that pretreatment, just like any consumable, has an expiration date. Mathis cautions that running expired pretreatment can cause poor washability, nozzle clogs, pump failure, and poor color saturation.
Not all pretreatments are equal. Some come ready for use while others require dilution. For products that require dilution, Mathis recommends using distilled water for the dilution ratio. “Not using distilled water can cause a calcium build up in the pretreat fluid path. This leads to clogs and mechanical component failure. Also, not using distilled water can aid in mold growth in your machine.”
“Using a pretreatment liquid that is designed specifically for the ink chemistry will give better results—white opacity, color brightness, and garment washfastness. Take a close look at the product labels to understand if there are health risks with handling pretreatment and the finished garment,” agrees Check.
Beyeler says the compatibility of the ink set and specific pretreatment is often overlooked and this shouldn’t be because the combination of the two yields maximum performance. “Processing parameters, including how much ink and/or pretreatment to use based on a specific garment application, are critical to achieve the targeted performance.”
There are options besides pretreating in house, like using pre-pretreated shirts. This takes issues commonly associated with pretreating and reduces the time required in the DTG printing process, notes Walker.
Liu says FIREBIRD’s full-immersion pretreatment system has accelerated the amount of companies able to offer pre-pretreated blanks. “In the future, fully pretreated blanks will be increasingly available directly to all DTG print shops.”
The message here—don’t rule out pre-pretreated garments. “We recommend our customers use pre-pretreated shirts, which are a great option for new print shops learning the DTG technology as well as quick and easy access to garments you are confident have been pretreated properly,” explains Crocker.
Hill stresses that pretreatment is not a one-size-fits-all process. “It’s always good to test different volumes on the fabric and then after printed and cure, do wash tests. Chart everything. Different styles of garments perform differently. Not enough pretreat and your prints are not solid. Too much and it will crack and flake almost always after the first wash. We advocate waiting 24 hours prior to your first wash test, but to launder at least three complete cycles to confirm your settings are good.”
“If done wrong or inaccurately via a hand spray method, you’ll drive yourself crazy and commonly blame things like the printer for issues simply caused by inconsistent pretreatment application,” cautions Ryerkerk. But, if done right—pretreatment leads to amazing prints.
A Key Role
The pretreatment step is integral to DTG printing. As many have stated, pretreat is the pillar, a foundation of DTG. Without pretreatment in most scenarios, the final print will be anything but vivid, which does not make for a wearable or sellable garment.
It is imperative to pair the right pretreatment with the correct ink, as well as host of other components in the DTG process. The second part in this series looks at various vendors in this space and products provided.
Jun2021, Digital Output
