Dye sublimation is the process of conversion of a dye from solid state to vapor on contact with printing media. Often, the pressure is also applied to facilitate the transfer. The Cyan-Magenta-Yellow colorants can be incorporated into a polymeric film and diffuse into the printing media on the contact with a digital heating element. As the dye becomes vaporized, it becomes fully integrated with the substrate, on a molecular level, which makes dye sublimation prints very durable; also the colors become brighter as the dye/pigment de-aggregates. As the dyes for the sublimation process need to be easily vaporizable, this limits the colorant structures to lower-molecular weight, apolar chemistries.
(image from DP3, Digital Preservation Portal)