Dot Gain

Dot gain happens when a halftone dot prints bigger on the shirt than it measured on the film positive or in the separation file, because plastisol spreads slightly as the squeegee forces it through the mesh and into the weave of the fabric. Screen printing typically sees 10 to 20 percent dot gain, noticeably more than the 5 to 10 percent common in offset printing on paper, simply because fibers absorb and hold ink differently than a flat sheet does. A 50 percent gray dot on the film can easily print closer to 65 or 70 percent coverage once it lands on a garment.

What that means for the buyer: the digital art proof pulled straight from the separation can look lighter and crisper than what actually comes off the press, especially in the midtones of a shaded design. Print the same file on a 4.5 oz ringspun tee and a heavyweight 7.5 oz fleece hoodie and the fleece will usually show more spread and a darker overall image, since the coarser fabric surface holds more ink per dot.

Shops compensate ahead of time by shrinking the dots slightly in the separation before burning the screen, a step called dot gain compensation, and by favoring higher mesh counts for detailed halftone work since finer mesh deposits less ink per dot and gains less on press.

Buyers sometimes see a shirt that reads darker than the proof and assume something went wrong. Correct that expectation early: some darkening is normal physics, not a mistake, and a shop that builds in compensation is doing its job right.