A printing press that can print both sides of the sheet in one pass is called a perfecting press. So instead of printing a sheet on one side and waiting for it to dry and then turning the sheet over reloading and putting it back through the press to print the other side it can be done in one pass. These were primarily limited to uncoated sheets and light to medium coverage.
Some presses can perfect on coated sheets now, although, it is taken on a job by job basis. Under the right circumstances it can save time and money. The sheet is actually flipped in the press and gripped from the other side of the sheet. The guide stays the same. This leads you to possibly needing to back trim the sheet to make sure all sheets are the same size. If the printed sheets vary in size the register will vary. Perfecting presses are real good to use on printed manuals with black over black content that is mostly text. It can increase your production by more than 100%.
-Picking a Printing Company
-What is a Page to a Printer?
-Offset Printing-What does it mean?
-Sizes of Printing Presses
Written by Buzz Tatom
The Odee Company