Imposition in Graphic Communications Graphic Output Processes Unit 2 Written by: Cheryl Rees

What is Imposition? Imposition is the positioning of the pages on the press sheet so that when the sheet is printed, the pages fall in the desired order, in the correct orientation (i.e., right-side up), and with the correct margins.

When determining which imposition is right for your particular project, consider these factors: Press sheet size Number of pages or size of project Length of run Weight of stock Crossovers and alignment across folds

When determining which imposition is right for your particular project, consider these factors: Trim size and trim allowances (plus lip if saddle-stitched) Mechanical capabilities of folding machines Paper grain Type of binding

When determining which imposition is right for your particular project, consider these factors: Ink problems (e.g., printed elements demanding different ink requirements that fall inline in the press sheet or have ghosting potential) Printing, folding, and binding capabilities Cost to operate the above equipment plus plates, paper, and so forth

There are numerous ways of positioning the pages on a sheet: Sheetwise Work-and-turn Work-and- tumble

What is Sheetwise ? When your printer prints your document such as brochure sheetwise, he may lay out four copies of the front of your brochure to print on one side of a 28” x 40” press sheet. When this side is dry, he can change plates, turn the stack of press sheets over, and print the opposite side of the sheet (the backs of the brochure), then trim down the stack of paper to produce four brochures from each press sheet.

Work-and-Turn or Work-and-Tumble? You can print the job work-and-turn or work- and-tumble (the only difference between these methods is how the sheet is turned over: either from side to side or end-over- end).

Work-and-Turn or Work-and-Tumble? In these two options, the four brochures would still be laid out on the sheet, but two front sides of the brochure and two back sides of the brochure would print on the same side of the 28” x 40” sheet noted above.

Work-and-Turn or Work-and-Tumble? Work-and Turn is a printing method where different pages are assembled so that they are on one plate. One side is printed and then the sheet is turned over so that you are using the same gripper edge and then the second side is printed. The product is then cut apart to make two finished items.

Work-and-Turn or Work-and-Tumble? Work-and Tumble is a printing method where different pages are assembled so that they are on one plate. One side is printed and the sheet is turned from front to rear so that you are using the opposite edge as the gripper edge and then the second side is printed. The product is then cut apart to make two finished items.

Work-and-Turn or Work-and-Tumble?

This would allow the printer to turn the sheets over (once they are dry) and run them through the press a second time exactly the same way on the opposite side of the sheet (“backing up the job”) without changing plates. The same plates would print the back of the sheet (two fronts and two backs of the brochure), creating four brochures (called “four-out” or “four-up”) prior to cutting and folding.

Work-and-Turn or Work-and-Tumble? Work-and-turn and work-and-tumble jobs save time and money by not requiring a plate change before printing the second side of the sheet. But, if you were to print the same job sheetwise, you could print (for instance) two colors on one side of the sheet and two different colors on the other side of the sheet without needing more ink fountains on press and without requiring extra passes through the press.

What is a Signature? In printing, the name given to a printed sheet which is to be folded. In stripping, the name given to the stripped flats to be printed and folded.