"Off-contact," for those who don't know, is the gap between the
bottom of the screen and the substrate (the item being printed), its
purpose is to improve printability during screen printing process.
For screen printing plastics, paper, and t-shirts (as well as other
light weight apparel), the "thickness of a dime" is a good starting
point for the off-contact gap. When you are printing thick apparel (like
sweatshirts) start with an off-contact gap of the "thickness of a
nickel" and increase or decrease as necessary. The goal of off-contact
screen printing is to obtain a good "snap-off" when the squeegee passes
over the stencil in the screen, resulting in a sharp printed image.
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