After being shrink wrapped with paper, the tympan is covered with polyester. This makes for a hard packing. There are two more layers of polyester which are hinged to the tympan with tape. Underneath the first layer is a position proof. Underneath the second layer goes the makeready proof. Adjustments with cutouts and tape are made to the makeready proof to equalize the pressure. Neither proof is in this photo, but a pale vertical line can be seen in the center of the tympan where the polyester opens up. For prints or broadsides, these pieces would have to be replaced with single sheets of polyester.