A few weeks ago, a customer called with an unusual problem. He was decorating a cotton shirt with a multi-colored graphic and having trouble aligning the layers. The alignment issue appeared to be caused by the first layer of film shrinking after it was applied. The two layers registered correctly after cutting and weeding, but, after the application of the base layer, the registration was altered so that the graphic could not be finished.
I consulted with our manufacturer’s representative and with Todd Castle, our Lexington branch manager. We discovered that it was not the film that was shrinking. It was the shirt itself. Sometimes new garments will shrink after the first pressing. We recommended the customer pre-heat—and therefore, preshrink– the shirt before applying the film.
During the recent NBM Fort Worth trade show, I had a conversation with Johann Giorsetti, the new head of Siser NA. Johann had been experimenting with the same issue and had a different take. He confirmed that the problem is indeed caused by the shrinking of the garment and suggested that we short-circuit the problem by using a shorter pressing cycle on the first layer. In order to grasp this fully, it might be helpful to review the standard procedure for layering t-shirt graphics.
First you apply the bottom layer; in this case, the black outline on the Cougars graphic.
You would press this for a full cycle: 20 seconds if you’re using Easy Weed. Then, apply the second layer and press that too for a full 20 seconds. For more details on this process, refer to my HotMark 70 Primer blog post.
The problem here is that the repeated heating of the garment causes the fabric to shrink, which causes the first layer to shrink, which screws up the alignment (See Fig 1).
The Quick Press Solution
There are two approaches: The first is the quick press short cut.
With the quick press short cut, you simply use a hot peel film like Siser Easy Weed or EnduraTex HOTPeel and apply the lower layer in about 10 seconds. Then peel the liner hot and immediately apply the second layer for the full 20 second cycle. This quick application of one layer atop the other prevents the misalignment because the garment doesn’t have time to shrink before the upper layer is applied. The result; a fast and perfectly registered multiple layered t-shirt graphic (See Fig 2).
Yes, it’s also washfast. I tested these yesterday and none of the quickly applied graphics delaminated in the wash.
What About Cold Peel Films?
What if you don’t use hot peel film? Does this process work with good old HotMark 70, FirstMark or VideoFlex? In short, no. Pressing the first layer for ten seconds, is okay, but these are cold peel films, so trying to remove the liner before the shirt cools is not a good idea.
The film will probably come up with the liner (See Fig 3).
You can try pressing the lower layer for ten seconds and allowing it to cool, but that process will simply put you back where we started: misalignment.
Fix it in the Design Phase
So, if you’re using a cold peel film, you take the second approach. You design around the problem much like large format sign shops design for raster and vector alignment tolerances on print and cut graphics. Throw in a little “fudge factor”. Simply enlarge the border area between the top and bottom color layers in your design to allow for shrinkage. Then use the standard method outlined above. After you’ve applied the lower layer and allowed it to cool, remove the liner. Then position the upper layer so that it’s centrally aligned on the lower, and apply. The result is a stunning, multi layered graphic you and your customer will be proud of. (See Fig 4).
So, if you’re using Siser Easy Weed or EnduraTex HOTPeel, you can produce more accurate alignment of color layers by taking advantage of the film’s properties and pressing the lower layers for ten seconds, then quickly applying the upper colors. If you’re working with more traditional film, just give yourself a better margin for error.
Whether it’s CAD transfer film, plotter vinyl, or digital print media, there are few materials issues that can’t be fixed with a little modification in the design phase.