Why Black Ink Isn’t Truly Black in Sublimation

Black designs should come out deep, rich, and jet-black… yet sublimators know the frustration: you lift the press and instead of a true black, it looks charcoal, brownish, or even slightly purple. The ink was black on screen, so why is the print not?

Why isn’t black sublimation ink truly black?
Because sublimation ink is made from dyes (not pigments) and there is no stable pure black dye that can withstand sublimation temperatures. Manufacturers create “black” by mixing colored dyes (cyan, magenta, and yellow) to visually appear black. When the ink is heated, each dye turns into gas at a slightly different speed, so the colors don’t convert evenly. That’s why what should look jet-black can shift toward brown, purple, or green after pressing.

Sublimation ink behaves differently from pigment or screen-print ink. Since sublimation uses dyes — not true black pigment — manufacturers create “black” by mixing CMY dyes to achieve a visual black. During pressing, heat turns the dyes into gas. As that happens, magenta often becomes more dominant, yellow shifts on warmer substrates, and each dye absorbs differently into polyester fibers. The result? Instead of a deep pigment black sitting on top of the material, sublimation produces an absorbed, chemically bonded “optical black” that can vary in tone.

In this article, we’ll take a closer look at why black doesn’t sublimate as a true black and discuss simple adjustments that can dramatically deepen your blacks and improve the consistency of your prints.

Key Takeaways