Using the curtain coating method, all types of finishing materials with low or medium viscosity can be applied on flat workpieces with straight or slightly rounded edges (without paying special attention to the workpiece thickness). The finishing material quantity to be applied, with a lower limit of ca. 50 g/mq (2 mill wet film) is determined by opening and closing the coating head aperture and changing the feed rate of the workpiece. Curtain coating machines are available with one or more coating units, wich can be quickly exchanged for a new finish type or colour.