If you’ve been in book or magazine printing for any length of time, the term “signature” is familiar to you. You probably think automatically about how your print book or magazine will break down into the most optimal press signatures to keep the printing cost down.
On the other hand, if you’re used to designing and printing flyers, large-format signage, and other products without multiple pages, then the term signature is probably new to you.
A signature is a press sheet with a certain number of pages printed on both sides, folded and trimmed such that the pages are all consecutive. Pages are laid out in this way (called a press imposition) so that four, eight, sixteen, or even thirty-two pages can be printed at the same time (if the press is “perfecting,” or printing both sides). If the press is not a perfecting press, then one side of the sheet is printed at a time. The ink is then allowed to dry. Then the job is “backed up.” (That is, the stack of press sheets is turned over, and then the sheets are fed through the press again–often with new press plates–to print the other side of the press form, which is the name for an unfolded signature.)
You can do the same thing with a smaller job. In this case, you would just print more than one copy of the job on a press sheet. For instance, if you’re printing a four-page, 8.5” x 11” (when folded) brochure, you might lay out two of these such that they will be printed simultaneously on a press sheet. In fact, to avoid changing the plates, you might even place one two-page spread face up and the other face down on the same sheet. In this way, without changing custom printing plates, you can print one side of the sheet, dry the ink, and then flip the stack over and print the other side of the sheet (called work and turn or work and tumble, depending on how the press sheets are turned over—side to side or end over end).
I know all of this may be confusing or maddening. But here is how it is relevant to commercial printing products with multiple pages.
The Case Study
A client of mine is producing a relatively simple print book. It is 5.5” x 8.5”, with 60# white vellum text paper and a 12pt. cover. The cover will be coated with a luxury matte film laminate. The book will be perfect bound. It will also have a 16-page insert printed on 80# gloss coated text paper. All told, the text will be 288 pages, and the insert will be 16 pages, so the total page count will be 304 pages plus cover.
Now, back to signature work. This would be absolutely the same if the product were a magazine. As long as we’re doing multi-page work, like a catalog, magazine, or print book, we talking about press signatures.
A 288-page book can be composed of 72 4-page signatures (highly inefficient), 36 8-page signatures, 18 16-page signatures (more reasonable), or 9 32-page signatures (ideal). Think about it. If your book page size is small enough and your press sheet size is large enough to fit 16 pages on either side of a press sheet, you can produce the entire print book in nine press runs (as opposed to 72 press runs if you can only fit four pages on a press sheet: two on either side of the page). Less time, less money. Also, fewer consumables such as press plates, fewer wash-ups, and therefore less labor.
If you take a sheet of paper, draw a rectangular press sheet, and rule out sixteen pages on this drawing, you can visualize what I’m saying. Now, write 40” on the long side of the rectangle and 28” on the short side. This is the total length and width of the press sheet, so you can further label the drawing by noting 8.5” (length of the individual pages) in each of the smaller book pages within the large rectangle across the 40” dimension and 5.5” (width of the pages) for each book page across the 28” dimension.
Of course, this assumes your press is large enough to accept a 28” x 40” press sheet.
When you have drawn out this miniature press sheet diagram, you will see that the long side will accept four 8.5” page dimensions equaling 34” (close enough to the 40” length to allow for gripper margin, printer’s color marks, and bleeds). The short side of the sheet will accept four 5.5” book pages, totaling 22” of the total 28” width of the press sheet.
So this is an economical use of the press sheet (less waste, and more print book pages per press sheet allowing for fewer press runs).
The Insert
My client’s insert will be 16 pages. It will be printed 8 pages on either side of the press sheet, so presumably it can be produced “two-up” on a 28” x 40” press sheet. This just means that when the press signature is folded and trimmed, you will get two full 16-page signatures from each press sheet. As noted before, the insert paper will be a gloss text sheet, and the book text pages will be uncoated book paper.
So this will be the marrying of two separate paper stocks: one a single, 16-page gloss text signature containing photos (which will look crisper on a gloss coated stock) and nine 32-page text signatures on an uncoated 60# offset paper.
Now the insert can’t go just anywhere. It has to go between press signatures. This may be a problem editorially. For instance, the gloss coated photo pages may pertain to certain pages of the remaining text. But if they all have to go together (all sixteen pages), and they all have to be positioned between text signatures (between any two of the nine comprising the text block), then their placement will be constrained.
Options
Let’s say you had money to burn. You could do things slightly differently. If some of your text signatures were shorter than 32 pages (let’s say two 16-page signatures in one position in the print book), you would have more options for placing the insert. Conversely, you could break the 16-page photo signature into two 8-page signatures and position one in the first half of the book and the other closer to the end of the book.
Either way, you would be decreasing the size of a press signature and thus necessitating more press runs to create the same book (plus new plates and ink wash-ups, so more labor, more materials, and more time on press at the printer’s hourly rate). You may still want to do this, for editorial reasons (pertaining to the content of the print book rather than to its most efficient manner of production).
What You Can Learn from This Case Study
If you are doing signature work, the first thing to do is think in terms of signatures. This will gradually become an automatic approach. Ask your printer about the size of the press and the size of the largest press sheet it will print. (Some presses will even print a 50” sheet.)
Then think about the number of book, magazine, or catalog pages you can get on a sheet and what size they must be. You will need to ask your printer how much space he will need for color bars and other printer’s marks, for the commercial printing press gripper (to pull the press sheets through the press), and for bleeds on the book pages. You’ll need to leave this much space as you determine the page size of your book, catalog, or magazine.
Your printer can teach you how to fold a sheet of paper to create a model of a press signature. You can then number the pages to see how the press form (the unfolded press sheet) can be printed and then folded into a little 8-page, 16-page, or 32-page booklet, after which these little booklets can be stacked and then bound together.
It’s also most useful to see all of this actually happening at a printer’s plant (to see the printing of one side of the sheet and then the other), then to see the folding, signature stacking, binding, and trimming operations that yield multi-signature products.
Once you have seen all of this being done and also have the little folded models and drawings of the press sheets that you have made, you will find it a much more intuitive process to lay out each signature of a print book and to understand where you must position an insert produced on different paper.
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