If I'm doing shirts with different designs, I do it by eye. If there is no visible center crease, I'll press my own by folding the shirt in half at the shoulders and bottom. Check to see if the neck and everything seems right and then press a crease. Then I'll lay the collar just over the top edge of the press and visually place the crease down the center and check to see if there is equal overhang on the left and right sides of the press. I'll then use the 3 or 4 fingers down from the collar method of placing the design and visually center it.
If I have to do dozens of shirts with the same design for the same person. I will actually center the shirt on the press the same way, but I would measure the location of the graphic on each shirt. The buyer would expect the design to be in the exact same spot on every shirt.
I say "would", because so far I am still working on my first sale that is 36 shirts to the same person with the same design. Fortunately, it's someone I know that is willing to wait for me to learn all this stuff.
A forum community dedicated to T-shirt merchants, professionals and enthusiasts. Come join the discussion about graphics, commerce, dyes, prints, collections, guides, displays, styles, scales, equipment, accessories, reviews, classifieds, and more!