One upon a time, the only reasonable way to added a design to a t shirt was screen printing. Screen printing is what it sounds like, a process of applying a design to fabric using a screen. Part of the holes of the screen are filled or blocked, and the printing ink goes through those that are open. By this process, you can only print one color at a time. Each different color on a design requires a separate screen. The cost of making these screens is high enough that it only pays to buy printed garments in batches of at least six per color printed. One color – 6. Two colors – 12. Etc.
Direct to Garment Printing
A newer process is direct-to-garment printing. Once again, this process is what it sounds like. A garment is placed in a printer, and ink is applied directly from an ink-jet type print head. We’ll talk about direct to garment printing another time, but it has the limitation that it works best to apply designs to flat pieces of cotton, and requires a costly printer. Designs of many colors can be printed. Single garments can be economically printed.
Dye Sublimation Printing
Enter dye-sublimation printing, or transfer printing. This technique can be used to apply designs to polyester fabric, and to a wide range of substrates which have been treated with a dye-absorbing polymer. The key to dye-sublimation printing is a special paper treated with a surface on which an ink can be printed, but which doesn’t absorb ink. Regular paper is porous, and absorbs inks. The surface of transfer paper is easy to print on, but doesn’t absorb ink. Instead, the ink dries on the surface. Later, the ink can be transferred by heat and pressure (or heat and vacuum) to a polymer surface, such as polyester fabric, that absorbs the ink.
Like direct to garment printing, dye sublimation printing can be used to print multicolor designs economically on as little as one garment. It can also be used to transfer designs to hats, coffee cups, ceramic tile, etc. Since the ink dissolves deeply into the polymer, the design is wash-proof, and durable. All that is required is a printed paper, a polyester fabric or polymer-treated surface, and a gizmo to press the paper against the surface and heat it for ten seconds or so.
See the sublimationprocess