Ink Opacity

Opacity comes down to pigment load and deposit thickness: enough titanium dioxide or dense colorant packed into enough ink sitting on the fabric, and the garment color beneath simply can't show through. A well-formulated opaque plastisol can cover solid black in a single pass at the right mesh count; a lower-opacity ink, or the same ink printed too thin, lets the shirt color bleed through and shift every color in the design toward whatever's underneath it.

This is the reason the exact same four-color design costs more and looks different printed on a black Gildan 5000 versus a white one. On white, most spot colors print directly with no prep. On black, low-opacity colors, pastels especially, need a white underbase flashed and cured before the color layer goes down, adding a screen, a flash station, and real time to the run — buyers who proof a design on a white mockup and then order it on navy or black are often surprised the quote changes.

Pros balance opacity against hand feel deliberately: stacking more ink for full coverage makes a heavier, stiffer print, while a thinner, softer deposit sacrifices some opacity for a lighter feel. High-density and puff inks lean toward the heavy end by nature; discharge and water-based systems trade opacity for a print that disappears into the fabric.

The common misconception is assuming any ink covers any shirt color equally well straight out of the tube. Opacity is a spec, not a given — a design meant for dark garments has to be built with an underbase and opaque color choices from the start, not patched in after the proof comes back wrong.