High Solids Acrylic (HSA) Ink

High Solids Acrylic, or HSA, is a water-based ink loaded with a higher percentage of solids than standard water-based formulas, letting it reach opacity closer to plastisol while still curing water-based style, typically around 320°F, and drying into the fibers rather than sitting on top as a film.

It's the ink system behind a lot of premium soft-print branding you see on boutique streetwear and higher-end team merch, full-color art on a black 100% cotton tee that still feels like almost nothing is printed there. Compared to standard water-based ink, HSA holds up better on darker garments without needing a heavy plastisol-style underbase, which is exactly why it costs more per print.

Printers choose HSA when a client specifically wants soft hand plus dark-garment opacity in the same job, something older water-based inks struggled to deliver without multiple passes. It requires tighter humidity control and more disciplined screen reclaiming than plastisol, since water-based chemistry dries in the screen faster if a shop isn't set up for it.

Buyers often lump HSA in with any water-based ink, but not all water-based inks print bright on black, cheaper ones need a discharge base or heavy layering to get there, while HSA is formulated specifically to skip that step.