Sublimation T-shirt printing involves printing onto a special sheet of paper first, and then transferring that image onto another material ( this is usually polyester or a polyester mix/blend).
The ink is then heated using a heatpress until it disintegrates and blends into the fabric.
Sublimation T-shirt printing will generally cost more than other methods, however it lasts longer, and will not crack or peel over time, unlike other shirt printing methods.