Apparatus is described which, in use, applies a thin film of a wetting agent, such as water or a water-based solution, onto paper or other print medium before applying a liquid toner. The wetting agent is applied at a predetermined distance from an image transfer area. The wetting agent acts to promote adhesion of the liquid toner to the print medium. The adhesion of the liquid toner to the print medium is further improved by supplying the wetting agent at a temperature higher than room temperature.