The past few years have brought changes to almost every industry, and decorated garment production is no exception.FULL STORY
Digital Decorating: Direct-To-Garment
Effective DTG Printing on Dark-Colored Garments
When working with the direct-to-garment (DTG) printing process, full-color, photographic-quality prints on black or dark-colored garments are achievable with some set parameters and experimentation.
Whether they are related to screen printing or direct-to-garment (DTG) printing, the “help-me” calls I take every week have a common thread: Clients are having trouble printing white ink on dark garments.
In reality, anyone can print on light-colored garments, regardless of the decoration method. The trick — or complication — with this common concern comes from printing an ink color that is lighter than the garment color and using a white underbase to make it all work. For example, printing a full-color, photographic image on a black T-shirt can be a challenge.
We use water-based inks in DTG printing, and the colors (CMYK) are translucent. To see the image at all, we must first apply a white base print and then add colors on top. This base print is the key to a bright and vibrant image. Get the underbase right, and the rest of the print naturally will fall into place.
All T-shirts, sweat shirts or plackets are not created equal. Some garments are better suited for a bright and crisp printed image than others simply because of the fabric weave and finish. This will require some experimentation on your part. And yes, there will be spoiled garments involved. But it’s important for you to see how various garment brands and styles will take the ink differently. In doing so, you’ll see that the same printed image will be different from garment to garment.
Ask your equipment manufacturer or distributor to talk about the garments they have had success printing, and which have caused headaches in getting a bright, vibrant image. They’ve already done plenty of testing so they can demonstrate their machines at maximum capability. They’ll also have a list of garments they wouldn’t touch when it comes to this printing process. DTG printing is a more delicate ecosystem than screen printing, and the slightest variation in garment weave and surface will impact the resulting image on the shirt.
The answers your suppliers give may surprise you. Just because a garment is a popular name brand or style doesn’t mean it is the best garment on which to print. Look for a garment that has a nice, tight weave to hold the ink better, and a smooth surface to accentuate the fine detail that DTG printers are capable of achieving.
The absolute best substrate is 100% cotton fabric, because the water-based ink systems for DTG printers specifically are made for printing 100% cotton fabric.
You still can print on fabric blends down to 50% cotton/50% polyester, but 100% cotton always will yield the best, most vibrant print, as well as the best washability after the sale.
Be sure to stick with the same brand and style of shirt within the same production run. While two different shirt brands may give you totally acceptable and saleable results, showing them to the customer side by side may send up a red flag when the images vary between these brands.
When I get calls about people struggling with printing, they nearly always first proclaim that the problem is the ink. However, 99% of the time, it’s something else the operator is doing incorrectly that is the root of the difficulty.
Two things happen with DTG printing when it comes to issues on dark garments: Either the print looks dull and faded, or the print has washability issues. These problems nearly always are due to improper pretreatment application.
Apply too little pretreatment, and your print will appear dull and washed out. Add too much, and the garment will have a sheen and stiffness across the entire shirt surface in the treated area, your image may even wash out completely. In this extreme case, the ink has not adhered to the fabric at all; it is just resting atop the pretreatment solution on the shirt and the ink washes away, along with the pretreatment, in the first washing.
It takes a little practice to get a correct print. When you change garments or brands, you need to do more testing with pretreatment application. That means a little spoilage, and a little more time spent on your craft.
In DTG classes, we demonstrate pretreating using a hand-held paint sprayer. Remember, more is not better when it comes to applying pretreatment.
You simply need to apply a mist of pretreatment to a garment instead of soaking it with the solution. Using a hand-held power sprayer, spray back and forth a couple of times across the garment, taking about five seconds to get the right amount of solution on the shirt.
An automatic pretreatment machine eliminates the variable of inconsistent pretreating. If you have three operators in your shop all pretreating garments, the result will be similar to fingerprints — no two people pretreat exactly the same way. An automatic pretreater will pretreat each garment in exactly the same manner each time. Dial in your ideal time/amount and each shirt will be consistently pretreated, thus eliminating the guesswork.
Because DTG machines use water-based ink, proper humidity is critical to the process. You need to maintain at least 40%-50% humidity in the room at all times. If your humidity level is below 40%, you can expect ink-clogging issues in your print head.
Your room temperature also is important. If it’s too cold, the ink flow will be sluggish, resulting in dull images. Too hot — in the 95˚F or higher range — and the ink can start to dry up in the print head. A typical office temperature of 72˚F is ideal for best results.
You generally have control of the amount of ink applied in your white underbase through your RIP software. Maximum ink laydown commonly is not necessary for a white underbase. Experimentation will help you pinpoint that “happy place” where you achieve an ideal bright white base with the least amount of white ink required. Remember, the colors are translucent, so it is imperative that you have a crisp, white underbase before proceeding to the color pass on your machine.
CURING THE PRINTED GARMENT
Sometimes, a print will look great when you remove it from the DTG machine, but can dull during the curing process. With a heavy laydown of wet ink, the heat press could potentially press this wet ink down into the fabric, resulting in a dull finished product. To combat this, first hover the heat element over the image to achieve a surface cure of the ink while keeping it on top of the fabric. Second, cut back on the pressure from your heat press. Medium pressure is more than sufficient to cure the ink and maintain the image’s brightness.
DTG printing on dark garments can be challenging, but easily remedied. Achieving crisp, vibrant, dynamic finished images on shirts can be attributed to: 1.) the proper shirt and fabric; 2.) the correct amount of pretreatment; 3.) a good environment for your printer; and 4.) laying down enough white ink to achieve a bright white underbase.
Terry Combs is a 35-year veteran of the garment printing industry, and has managed production shops large and small across the country. He is the author of the ebooks “Screen Printing: A Practical Guide” and “Direct-to-Garment: A Practical Guide,” both available at Amazon.com. For more information, visit terrycombs.com.
Like this article? Read these other digital decorating articles at impressionsmag.com:
• “The Digital Direction”
• “Pricing for Profit with Direct-to-Garment Printing”
• “Trends and Innovations in Digital Heat Printing“
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