A fluid for application onto a substrate is provided in a cavity of a hollow cylindrical application roller that has porous roller wall. Before reaching the transfer point to the substrate, fluid is regionally selectively pushed back away from the outer shell surface of the application roller, into the porous roller wall, by a knockback pressure, in order to regionally selectively produce the effect that, at the transfer point, fluid is located at the outer shell surface of the application roller or no fluid is located at the outer shell surface of the application roller. A regionally selective application of fluid onto a substrate may thus be efficiently produced.