Judging a Book by Its Binding

With the steady adoption of all sorts of digital printing systems, more printers—and non-printers—are now producing soft- and hard-cover books. There are loads of adhesive binder models out there, from tabletop models to “big iron” machines that take up lots of floor space.

Many small- and medium-size digital print shops will purchase a perfect binder and assume they’re good to go with a quality product. While such shops are now capable of producing a bound book, many of them don’t know the standards by which soft-cover, adhesive-bound books are measured.

Yes, that’s right, binding standards. The two tests most commonly used are the page-pull and flex tests.

  • The page-pull test measures the strength of the page binding perpendicular to the spine. A testing machine (typically a Moffett unit) literally pulls a page out of the binding using a hydraulic system. The amount of force required is measured on a gauge; the minimum standard for this test is 30 lbs. of force. If it takes higher values to pull out pages, that’s a good thing. Pull testing is conducted on pages in the middle and at both ends of the book.
  • The second widely used test is the flex test. This involves another testing machine that “flexes” the page back and forth at 50 cycles per minute, with two pounds of force pulling on the page. A baseline standard for this test is 500 flexes without failure. Some printers set much higher standards. Yearbook printers, and other “memory product” printers, may require the binding to withstand 1,000 flexes, for example.

Printing Industry of America has an excellent video showing the complete testing process:

It’s critical to know the bind quality of the book you’re producing, and that it’s up to par. You don’t have to test every book, but pulling one sample from a run and testing it is a good idea.

Don has worked in technical support, sales, engineering, and management during a career in both the commercial offset and digital finishing sectors. He is the North American representative for IBIS Bindery Systems, Ltd. of The United Kingdom.
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  • Leslie Altobelli

    Do you know how to test a perfect bind in printing?

  • Werner R

    Don – this fellow does it all wrong. First the Moffett is not hydraulic, it is pneumatic!
    The loading of the flexing machine is wrong, we always leave at least 3 sheets
    on each side loose, floating. I worked with these testing machines for over 25 years and educated many people on it.
    Werner Rebsamen
    Professor Emeritus RIT
    Bookbinding expert

  • Dave

    The page pull should be calculated in pounds per linear inch. Not all books will meet the set standard as the video states due to the dimension head to foot. Excellent page pull results should be 4.0 lbs. per linear inch.
    Dave Senter