Dye sublimation consits of three things, these being

1. Dye: to impregnate colour into a material.  Many times this colour change is permanent.
2. Sublimation: a change directly from the solid to the gaseous state without becoming liquid.
3. Polymer: consisting of large molecules made up of a linked series of repeated simple molecules.

Therefore dye sublimation is when:   Solid dye particles are changed into gas using heat and pressure, then bond with any polymers present, and change back into a solid state.

As you may already be aware a dye can only darken a material, and so we use white garments only for sublimation, which will then provide an excellent result.