DTG or Sublimation? Which is Right for Your Shop?

If you're going to invest in one digital technology, this successful decorator's experience can help you decide between direct-to-garment or sublimation.
Sept 1, 2007

By Mark Collins

As an owner of a digitally focused garment printing shop, I am frequently asked whether direct-to-garment printing (on cotton) or sublimation (on polyester) is the best printing process. Each person who asked that question had a different reason for asking and a different definition of "better." Some were customers who wanted the best image possible, and some wanted the best price. Some only wanted cotton, and some needed T-shirts with moisture-wicking capability. Some customers needed only a few shirts, while others wanted large quantities.

I adopted sublimation as soon as I heard about it, seeing it as one more service to add to the list of the services that I was already providing. I look at the sublimation process as a tool in my toolbox, just like my Hopkins six-color manual screen printing press and my dryer. These tools supplement my business by broadening the services I offer.

That being said, I love the ease and speed at which I can go through the approval process with digital printing. With direct-to-garment printing, I can send a digital copy of the image to the printer and make any necessary changes to gain approval from the customer — all while he is standing there. This process usually takes no more than five minutes and is similar — and just about as fast — for sublimation. One small difference is that sublimation involves printing the art on transfer paper and applying it with a heat transfer press. The biggest difference, of course, is the fabric on which designs are printed.

As no process can be everything to everyone, it's difficult to choose between the two, but a side-by-side comparison would be interesting. Here's what I found out:

The DTG Process
Direct-to-garment (DTG), also known as inkjet-to-garment printing, involves using a printer to print ink directly onto a cotton garment and curing the ink with a heat press. There is very little set-up time, which usually involves little more than sizing the image correctly in Adobe Photoshop or CorelDraw. There is one limitation — I can print only light shirts via DTG because I have not yet found a printer with a "white ink solution" to inkjet print on darks that I think could work in my production environment.

Since my shop prints about 275 to 350 shirts a day using DTG, I shopped for a printer that could produce that volume without much maintenance or down time. I chose the Brother GT-541 and have found it to be a reliable and fast four-color (CMYK) printer that works for my needs.

I looked at printers with 8-color printheads that can produce a larger color gamut and finer detail, but the speed was more important to me.

Inkjet printing directly to a shirt obviously cannot yield the same image quality as inkjet printing to paper — just as printing on copy paper can't compare to printing on high-quality photo paper. The substrate dictates the limits of your image quality.

Knowing that, I shop for blank garments that are closer to "photo" paper than "copy" paper. I look for thread count and a fine, dense weave that will provide a better print surface. I avoid garments with too much fluff, or pile, because that inhibits the inkjet process. Ring-spun cotton is softer and more expensive, but that soft hand comes from all the tiny fibers that stick up off the fabric.

These tiny fibers block some of the sprayed ink from making a solid bond with the shirt and little bits of the image wash away as the fibers wear off. These tiny fibers also can lift up immediately after being printed, exposing areas that did not get full ink absorption. Avoid both problems by using shirts woven from open-ended yarn, or yarn that is card spun.

Sublimation
The sublimation process starts by printing sublimation ink (technically it's dye, not pigmented ink) onto a sheet of transfer paper. The paper is then placed on a polyester garment that is loaded face up on a heat press set to about 400°F. The shirt stays under heat and pressure for about 35 seconds. (Times and temperature settings vary according to the type of polyester garment. The best are made with polyester that is tested for durability under this kind of high heat.)

Polyester has a peculiar characteristic in that it "remembers" the highest heat that it comes into contact with, so picking a garment that is made for sublimation will save a lot of aspirin — and a lot of ruined shirts.

The fact that the image prints to paper means sublimation can produce a very detailed image. The most impressive prints that I have ever produced have been with sublimation. In my opinion, no other printing method can provide a clearer, brighter or more vivid image than sublimation.

The durability and wash-fastness of the image are unsurpassed because the method actually re-dyes the fabric on a molecular level. The heat press brings the polyester up to a temperature just below its melting point. That "opens" the polyester fibers and vaporizes the ink/dye, which is injected, or sublimated, into the fiber. When the heat comes off the shirt, the molecules "close" as the shirt cools down. You cannot feel where the print starts and stops — the image literally has no hand. In other words, you cannot feel any difference between printed and unprinted portions of the garment.

A Side-by-Side Comparison
One of my customers sells printed T-shirts to national parks and ski resorts nationwide. We do dye sublimation, direct-to-garment and screen printing for him. Servicing his account has been one of the biggest factors driving me to try new printing processes over the years, so it is fitting that my shop used one of his jobs as a test run.

I chose a photo image that been filtered in Photoshop to appear like a watercolor print. The image had vibrant blues and oranges that are difficult to reproduce, as well as some tricky text. My customer will be selling this image on performance fabric and cotton, so it is a good one to test. This photo came to me as a 300 dpi, 8" x 10" image and I did no color adjustment before I printed the first round of samples.

I chose to print the image the same size via DTG and sublimation in order to do a side-by-side comparison. I did the inkjet-to-garment print first, selecting a 6.1-ounce 100% cotton white T-shirt. Immediately I noticed a change from the original image file. The blue in the sky was darker, making the overall image seem overcast.

I know that color can be adjusted in Photoshop as needed. However, it must be done carefully so that in correcting one color, you don't change other colors in the image for the worse. There are many ways this can be done, but I chose to use Photoshop's Magic Wand tool, set at a tolerance of 32, to select the sky blue. This simple, one-click method selected color all the way up to the edge of the snowy trail behind the snowboard rider, leaving some of the blues inside unselected. For other applications, this would not be good enough, but I wanted to try it anyway.

Since the idea was to make the blue lighter without altering the overall image too much, and since DTG printing is somewhat forgiving, I thought it might work — and it did. It lightened the blue in the sky, which made the overall image look much better.

For my sublimation comparison, I printed the image on a white performance fabric shirt. To do that, I first printed a reverse of the uncorrected image onto transfer paper using my Epson 4000 inkjet printer loaded with sublimation inks. I checked the print for banding to make sure that it would be a good test print. Banding, which is caused by clogged nozzles in the printhead, can change the color and leave visible lines in the finished print.

I transferred the print using a heat press set at 395°F and applied pressure for 35 seconds. As soon as I pulled she shirt off the heat press, I could tell that it was a vibrant print that looked very close to the original on my computer monitor.

After close scrutiny under a bright light, I was satisfied that this sample would pass inspection and needed no color adjustment. I asked my business partner, Scott Reese, what he thought about the differences in the two prints.

Scott first commented on how bright the blue was on the sublimation print. As he looked closer, he noted that even though the blue on the DTG print was a different blue than in the original image file, it worked well as a sky blue. He said that if he had not seen the sublimated print, he would not have known the difference.

Scott also said the inkjet print worked well with the watercolor effect, while the sublimated print showed so much detail that the filter effect seemed unnecessary. The DTG print was Scott's favorite. I preferred the sublimated print because of its clarity, but I had to admit that both looked great.

After the side-by-side comparison, if I had to advise someone about which process — DTG or sublimation — is better, I would offer the following: "Take your pick. They're both great!"

Mark Collins of Halcyon Digital Corp., Asheville, N.C., sold his interest in a traditional screen printing company to open Halcyon and concentrate on digital decorating techniques. He teaches digital seminars for ISS and SGIA, and can be contacted via e-mail at mark@halcyonprinting.com.

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