Book Printing: Signatures Don’t Always Have to Be Four or Eight Pages

I just learned something revolutionary today. You don’t always have to make your signatures four or eight pages when you’re producing a print book.

Maybe most other people know this, but it had always been drummed into me that my clients could increase or reduce the page count of a print book only in increments of four or eight pages. The goal was to make as many 32-page signatures as possible, then go down to 16-pagers, and then 8-pagers. I had learned that 4-pagers were not ideal, since they would require handwork. They could be produced, but they would often cost as much as an additional 8-page signature.

Enter Digital Printing

I’m working on a book of poetry with a client. The first run will be produced digitally on the HP Indigo (a smaller-format machine, with an image area of approximately 13” x 19”). This is because it will be an edition of 30 review copies (to be followed, after corrections, by a 1,500-copy offset print run).

The designer came up with a book length of 82 pages. My initial reaction was to say the book needed to be 84 pages (five 16-page signatures plus a 4-page signature).

I was wrong—and only because the print book is digital and a perfect-bound product. Here’s the reasoning.

A saddle-stitched book must have 4-page signatures (at least). Two of every four pages are on the low-folio side of the saddle stitches and two are on the high folio side (“low folio” just means the front of the book; “high folio” means the pages are after the center of the book). A 2-page signature (one leaf, front and back) would fall out of the print book. There would be nothing for the staples to hold onto.

In contrast (and this is what’s new to me), once stacked signatures have been gathered, and the spine has been ground off prior to perfect binding, the signatures really are irrelevant to the strength of the book binding process. The glue will grip and hold onto even two pages or one single leaf of paper. Granted, according to the printers with whom I discussed this matter, you wouldn’t want to put a 2-page signature in the first or last position in a perfect-bound book. In this particular case, the glue could weaken and the pages could fall out.

In case you’re wondering, this is how this relates to digital printing.

The sheet size of an Indigo press is very small (about a 13” x 19” image area for the smaller Indigo presses). Therefore, you would normally print only 2- or 4-page signatures. You would then fold them (if appropriate), and then perfect bind them into your print book.

Another way of saying this is that designing a book to accommodate the largest signatures possible (32’s, 16’s) is necessary only for offset printing, in which large press sheets can accommodate large multi-page book signatures. Digital printing on equipment like the HP Indigo (electrophotographic presses), only requires 4-page signatures for saddle-stitched work. And for perfect bound books, either 2- or 4-page signatures are fine.

This is rather liberating. The press—not the perfect binder—determines the press signature length.

How You Can Use This Information

This is not as arcane as it sounds. It really will be useful to you. Here are some thoughts:

1. 1. Based on the length of your book press run, determine with your print provider which technology is best: offset or digital.

1. 1. If you are producing an offset print book on a heatset offset press, ask your book printer what page count is most efficient (least expensive, with the least amount of handwork required). Give him a target page count and see what he suggests (adding or removing a few pages). As an example, the same poetry book I’m working on with my client as a digital job will be reprinted on a heatset web press at a run length of 1,500 copies after all editors’ corrections have been made. I just requested pricing from the printer, and he can only produce an 88-page book (not an 82- or even 84-page perfect bound book). This is based on the kind of press equipment he has, not the perfect binding equipment.

1. 1. If you want to add a 2-page signature, put it in between larger signatures to make sure the glue and binding pressure keep the page from falling out.

1. 1. Consider this useful information if you want to bind a single sheet of thicker paper into a print book. For instance, in many graphic design magazines, you’ll find a single sheet of sample paper from a paper mill. This sample is often a cover stock, heavier than the surrounding magazine text pages.

1. 1. Remember that this only pertains to digital printing. Offset presses usually wouldn’t print just two pages (one leaf, front and back) unless the job were a single-page flyer.

1. This information also only pertains to perfect binding, not saddle stitching.

But you’ve got to admit. It’s rather liberating news. It gives you more options for the length of your print books.

This entry was posted on Tuesday, December 22nd, 2015 at 8:23 pm and is filed under Book Printing. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.