A method and an apparatus for controlling the vacuum distribution in an exposer for recording printing originals. The recording material for the printing originals is held firmly on a supporting surface by negative pressure. The recording material being attracted by suction by a vacuum pump via suction grooves machined into the supporting surface and via suction ducts connected to the suction grooves. For opening and closing the suction ducts, valves are provided, the valves being closed by the mechanical action of force from an actuator on a piston rod and opened by the action of compressed air on a piston in the valve. For opening the valve, an outlet opening for the compressed air is integrated into the actuator. In a printing plate exposer with an exposure drum, the suction ducts and the valves are located in the exposure drum, and the actuator is located outside the exposure drum.