Impression Sheet

A sheet of stout even paper, that fits exactly, without any play, the inside of the outer tympan: this sheet is used in fine work to place the overlays upon next to the parchment, and when a sheet of any work is thus made ready at a press, the succeeding sheets of the same work, at the same press, are made ready much more expeditiously, than if all the overlays have to be placed for each sheet on the tympan sheet. — See Making Ready.