A mold for imprinting a patterned region by imprint lithography is provided with a peripheral groove around the patterned region. The groove is connected, as by channels through the mold, to a switchable source for gas removal to prevent bubbles and for the application of pressurized gas to separate the mold and substrate. In use, the mold is disposed adjacent the moldable surface and gas is withdrawn from the patterned region through the groove as the mold is pressed toward and into the moldable surface. At or near the end of the imprinting, the process is switched from removal of gas to the application of pressurized gas. The pressurized gas passes through the groove and separates or facilitates separation of the mold and the moldable surface.