Vacuum tables

A method comprising:

• providing a vacuum table comprising:
• a vacuum plate separating a compound vacuum chamber from a substrate zone for receiving a substrate, the vacuum plate having a plurality of suction holes for conveying a gas flow from the substrate zone to the compound vacuum chamber;
• an evacuation port in communication with the compound vacuum chamber to evacuate gas from the substrate zone when a substrate is received over the suction holes of the vacuum plate;
• and
• a vacuum port for discharging gas received in the compound vacuum chamber to a vacuum source;
• partitioning the compound vacuum chamber to provide a first vacuum chamber to receive a gas flow through the suction holes and a second vacuum chamber to receive a gas flow through the evacuation port;
• installing a valve for fluid communication between the first vacuum chamber and the second vacuum chamber so that gas flows from the first vacuum chamber to the vacuum port via the second vacuum chamber, wherein the valve is controllable to vary a gas flow rate through the vacuum plate.