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Foresight saves you money, among other things. This is as true in commercial printing as it is in most other arenas of life. Printing paper is expensive (or even scarce at the moment in the United States). Therefore, it is smart to understand how to use it efficiently (i.e., how to avoid wasting space on a press sheet and trimming away and discarding unused, blank paper).
Signature Press Work
Perfect-bound books and saddle-stitched books are composed of signatures. Let’s say you have a 40” press, and your press sheet is 25” x 38”. If you lay out four 8.5” x 11” pages across the top of one side of the sheet and four pages immediately below these, and then you do the same thing on the back of the press sheet, you can print 16 pages at the same time. These pages will take up 34” along the 38” side and 22” along the 25” side. On either dimension there’s a little room for bleeds (which extend 1/8” beyond the trim), gripper margin (the mechanical device that grasps the press sheet and moves it into the press), and the printer’s control bars and targets (used to measure and maintain accurate and consistent color and to catch other press problems as well).
This is not an accident. Many years ago a commercial printing press manufacturer came up with the most prudent ways to produce multiple print book pages (that were in most cases based on a US-standard 8.5” x 11” page size) with minimal waste.
Once printed on one side, these press sheets can be turned over and fed back into the press to “back up the sheets” (print the opposite side). In most cases this is after a considerable amount of drying time to avoid the ink’s smearing and setting off onto the back of other wet press sheets, but if the printer is using UV inks cured instantly with UV light, the backing up process can conceivably be done immediately.
What this means is that a print book can be broken down into 16-page signatures (or, presumably, 4-page or 8-page signatures as well). That is, a 64-page book can be printed in four press runs (4 x 16 pages). If the press (and therefore the press sheet) is large enough, or the page size is small enough, even larger signatures can be printed. So, for instance, a 64-page book might be able to be printed as two 32-page signatures (two press runs rather than four). And the best thing is that the actual print book pages, along with the printer’s control targets, bleeds, and gripper margin, will take up the entire press sheet with minimal if any waste.
Once the commercial printing is complete and dry, the sheets can be folded and trimmed. And due to the position of the print book pages on the press form, once trimmed and folded the apparently random placement of pages on the press sheet will yield a trimmed and folded press signature with all pages in the proper order. Again, the printing press manufacturer was thinking ahead.
This is the basis of all press signature work (print books, catalogs, etc.), with pages constituting multiple, sequential press signatures.
Other Work That Doesn’t Involve Press Signatures
But what if you’re printing pocket folders? That’s not signature work, but you still want to avoid wasting paper. Another way of saying this is that for a pocket folder (open flat, with all the soon-to-be-die-cut slots and tabs), you want to take the space you need on a 25” x 38” (or other sized) sheet, but you don’t want to leave the other space blank. Anything left blank goes in the trash and you still pay for the waste paper. So maybe you can fit two pocket folders (flat, uncut, and unassembled) side by side on a press sheet. Less wasted paper. Great idea.
But it doesn’t stop there. Imagine six 8.5” x 14” newsletters on a press sheet, or four 8-page brochures side by side, or nine 4.5” x 6.25” greeting cards imposed on the press sheet (you can see drawings of these on page 96 of a book by Mark Beach, PhD, and Eric Kenly, MS, called Getting It Printed, which a close friend gave me thirty years ago and which is still my go-to book on custom printing).
Now think about this. In press signature work you position all different pages on a press sheet (no duplicates), but you can print 16- or 32-page signatures and therefore produce a long print book with fewer, rather than more, press runs (i.e., faster and at a lower cost).
In this case you’re doing something similar. You’re producing multiple copies of a final printed product simultaneously on one press sheet. Therefore you can not only save paper but also print your desired number of copies significantly faster than if you hadn’t ganged up the identical printed products on the press sheet. Faster equals less money spent.
Sheetwise, Work and Turn, and Work and Tumble
If your “multiple-up” pocket folders, business cards, flyers, newsletters, greeting cards, or whatever, all face the same direction on the press sheet, you print one side, let it dry, and then “back up the sheet” by printing the other side.
If all printed products face the same way on one side of the sheet, and you need to turn over the pile of printed sheets to print the opposite side, you must first change the printing plates so the opposite side of the press sheet prints correctly. This is called printing a job “sheetwise.”
But if you have half of the job facing up and half facing down (let’s say the back and front of a pocket folder), you can set up the plates on press in such a way that you only need to turn the pile of press sheets over once the ink is dry before “backing up the sheet.” That is, you don’t need to change the printing plates. This is called either “work and turn” or “work and tumble.”
The major difference between “work and turn” and “work and tumble” is the direction in which the stack of printed sheets must be turned (along the long or short dimension of a 25” x 38” press sheet, for instance). Your printer will determine which will be more efficient relative to the printed artwork, but again the main difference compared to “sheetwise” commercial printing is the fact that you use the same plates and therefore save money in platemaking and wash-up/makeready processes.
That said, if you want to use different colored inks on the front and back of a press sheet, it might actually benefit you to run the job sheetwise. That way you can print two PMS colors on one side, let them dry, change plates, and then “back up the sheet” using new plates and new ink colors.
Up vs. Out
This is a fine point and may be somewhat confusing.
When you say a press sheet contains four 8-panel brochures printed “four up” and “four out” (using one example from page 96 of Getting It Printed), that means there are four identical, complete printed products on a press sheet. You get four identical products when you fold and trim the press sheet.
In contrast, when you print fifty business cards at once on a press sheet and each one has a different person’s name, then the correct terminology is “50 up” (50 images laid out on a press sheet) but only “one out” (since each printed product is slightly different from all the others).
Another way of saying this is that “up” refers to how many products are physically laid out on a press sheet, while “out” refers to how many of them are the same.
The Takeaway
To avoid confusion, the best thing you can do is take this information to your printer, go on a press tour, and ask to see samples on press of sheetwise, work-and-turn, and work-and-tumble jobs. Also ask to see the difference on an actual press sheet between a “four-up and four-out” vs. “four-up and two-out” (for instance) print job. This will be a lot clearer when you can physically see the differences.