Terms & Techniques
Printing Terms and Techniques
When discussing printing with a printer you will find that he has his own language; the better you understand it, the easier communication will be. Let's examine some of the terms:
Backing-up. Printing the reverse side of an already printed sheet.
Form. In letterpress, type and other printing matter locked up in a chase ready for printing. In offset, refers to the printing plate. Can also refer to one side of a printed sheet.
Gang Printing. Also called ganging up. Printing a variety of different jobs on the same sheet of paper. After printing, the sheet is cut into the individual jobs.
Gripper Edge. The leading edge of a sheet of paper held by the grippers as it passes through the printing press. Paper allowance must be made for the gripper edge of from 1/4" to 1/2", depending on the kind of printing press used.
Grippers. Metal fingers that hold the paper onto the impression cylinder of the press.
Imposition. The arrangement of pages in a form so they will be in the correct order when the sheet is printed, folded, and trimmed.
Makeready. The complete process involved in getting the presses ready to run after plates have been inserted: register, ink control, feeder control, etc.
One-up, Two-up, Etc. When printing small units it is often more practical and economical to repeat the image many times (two-up, three-up, etc.), using duplicate plates on a larger sheet of paper, than to print it singly (oneup) on a small sheet of paper. The advantage is that the cost of duplicate plates is generally less than the cost of the additional press time that is required to print a single image on each pass through the press. This is especially true in offset lithography, for which duplicate plates are particularly inexpensive to make.
Preparation. Also called prep work. All the work necessary in getting a job ready for printing: camera, stripping, platemaking, proofing, etc.
Sheetwise. A printing procedure in which one side of the sheet is printed with one form, the reverse side with another, and in both passes through the press the gripper and guide sides remain the same.
Shells.
In order to save time and money on printing, the common (unchanging) part of a multi-color job is often pre-printed. At a later time it may be imprinted with the variable information. An example of this would be a three-color business card. The company logo and address could be printed in red and blue in a large press run. Later, employees names and phone numbers could be imprinted in black as needed on the pre-printed "shells" at much less cost than running all three colors each time new cards are required.
Work and Tumble. A printing procedure that allows the printer to "back up" a sheet without having to change printing plates. The plates for both sides of the sheet are contained in a single form; on the first pass through the press half the sheet receives the impression of Side A and the other half of the sheet receives the impression of Side B. The sheet is then tumbled; that is, turned over from front (gripper edge) to back, so that a new edge meets the gripper. With the same printing plate, Side A is backed up with Side B and Side B is backed up with Side A. Because changing the gripper edge means that adjustments must be made on press before printing the second side of the sheet, work and tumble is seldom used where close register is important. Also, because both ends of the sheet are used as gripper edges, extra paper must be allowed for margins.
Work and Turn. A printing procedure similar to work and tumble except that the second side of the sheet is printed by turning it over from left to right, so that the same gripper edge is used on both sides. Not having to change the gripper edge makes it much easier for the printer to get proper register. For this reason, work and turn is more widely used than work and tumble.