Few things are more disheartening to a trade bindery than unpacking a perfect binding job fresh from the printer, and having to call and explain why the beautiful six-color cover, with UV coating, is unusable. This happens more often than you might think and is especially tragic when you remember that the information printers and prepress departments need to set up work for perfect binding properly is readily available. The following guidelines should prevent imperfect perfect binding.
Preparing Text
For grinding off and trimming, signatures for perfect-bound books need overwork on all four sides of the page. The usual amount ground off at the spine by the perfect binder’s saw is 1/8″; Trims of at least 1/8″ are required at the head (top), foot (bottom), and fore (outside) edges of each page as well. These trim/grind-off requirements also apply to single sheets such as Docutech work. Many machines have a maximum trim in addition to this minimum–check with your bindery before you buy the wrong size paper.
Perforation is preferred at the spine fold of each signature and is acceptable on other folds since they will all be trimmed off. The spine fold should always be the last in the signature. Do not impose smaller signatures (like 4’s and 8’s) at the front or back of the book if possible–put them inside, with a 16 or other larger sign on the outside.
Your bindery can give you information on the minimum and maximum size and thickness book their machinery can handle. They can also tell you how many signatures their in-line collator/feeder will accept.
Covers
The most common problem seen with perfect bound covers is inadequate glue catcher area. When books run through the perfect binder, the spine area of the text block is covered with glue to attach it to the cover. The cover therefore needs to be longer than the untrimmed signatures at both the head and foot to prevent sticky glue from squeezing out and fouling the next book. Machine requirements differ, but allowing for a 3/8″ head and foot over and above the size of the folded signatures should be enough. Most binderies prefer to cut covers to fit their machinery.
Smyth-sewn softcover
For added durability or when using coated stock, you can enhance your text signatures by Smyth sewing them before glueing into the cover. This technique allows pages to lay flatter than in a typical perfect-bound book. Because the spine fold on the signatures remains intact, without perforations or grinding, the sewing keeps the entire text block secure, ensuring pages won’t detach from the glue. However, Smyth sewing is not compatible with single sheets.
Conclusion
Perfect binding can transform a book’s appearance, creating a sleek, professional finish. However, achieving a flawless result requires careful attention to detail and a collaborative approach between the printer, prepress, and bindery teams. By preparing text and covers according to these guidelines—allowing for proper trimming, understanding glue requirements, and choosing the right stock and grain direction—you can avoid costly issues and produce a high-quality final product. When using coated stock or requiring extra durability, consider Smyth sewing as an added reinforcement for lasting quality. With these preparations, you can ensure that your perfect-bound books not only look exceptional but also withstand the test of time.
