The principle of foil printing is transferring metallic material from a roll onto paper or some other printing material. Classic and raised foil printing differ from each other in their transfer method and technology.

With classic foil printing, the reverse side of the foil has an adhesive layer, which bonds to the transfer material under the combined effect of pressure and temperature.

Digital and i-Foil methods do not use adhesive material. With i-Foil, spot varnish serves as the adhesive.