February 2008—Tips for Smooth Signature Folding
Most books and publications with significant page counts are printed in “signature” form. Signatures are multiple-up page layouts and if properly planned, greatly reduce time and money in the bindery. Sometimes signatures are folded inline, right off a web press, others are folded offline on standalone folding equipment. Either way, signatures need to be properly folded and perforated prior to being bound. Signatures can have different page counts but the term “signature” is usually reserved for 8-, 12- 16- and 32-page forms while 2-, 4- and 6-page forms are typically called just that, forms.
Proper signature layouts can help you maximize your sheet usage and save you run time on the binder. Count on Muscle Bound Bindery to help you plan your next book or publication so your signature layout works for, not against you. Here are some planning considerations to keep in mind:
- Trapped Air:Most signature layouts naturally trap air. This is OK as long as they’re properly perforated at the head and backbone so all air can be squeezed out during the folding process. Perfing helps avoid wrinkling in the paper and allows the fold to be tighter, flatter and in better register. There’s a big caveat; these perfs can’t be too heavy, or they’ll fall apart during signature feeding onto the binder. As a general rule, there should be more paper than perf on the spine edge.
- Pushout: Paper has a third dimension: thickness. All signatures, but especially thicker ones, require copy to be staggered to account for “pushout,” sometimes called “creep.” If copy imposition isn’t done properly, some pages will have copy too close to the spine and others too close to the face of the book. If you’re dealing with 32-page forms, you could experience “head to foot” image variation as well. For example, consider a small format project, 4”x 6” final size with bleed tabs at the face and lots of crossover images. If you choose 32-page signatures to minimize the number of forms needed, you’ll likely see ”head to foot” variation in bleed tab positioning and crossover images. In cases like this, folder and binder operators will have more control if you use 16-page signatures instead. Again, each project is different. The best way to be sure is to ask us first.
- Press sheet size: This may seem obvious, but your press and final book sizes determine the maximum page count of your signatures. If your project has images bleeding off the face, your signatures need to be larger, potentially forcing you to downgrade the number of pages per signature, which increases your cost. Make sure you catch this potential problem during the estimating stage.
- Too Thin: Thinner stocks may be attractive because of their lower price, but paper that’s too thin is more prone to tearing, wrinkling and can be prone to unsightly dog-ears when folding. The additional waste and slower production times caused by a poor paper selection for a particular signature layout will likely negate any paper cost savings.
- Too Thick: On the other hand, if your stock is too thick, you’re more prone to experience pushout and register accuracy problems.
- Just Right: Waste can be minimized by choosing an appropriate paper stock that’s right for your signature fold. Generally, 60# uncoated or 80# coated are safe bets for most configurations.
- Consistency Between Signatures: Make sure all signatures in your project are the same size. All signatures should have consistent head, foot and face trims as well as grind off throughout the book’s signatures sequence. Provide a rule up specifying where the trim-offs are positioned on the sheet.
The Muscle Bound Advantage
At © 2010 Muscle Bound Bindery, we know that planning and precision is the key to a successful book project. Let us shoulder the responsibility for helping you get all components done right. Give us a call today to begin planning your next successful project.
For more than 40 years, Muscle Bound Bindery has offered a complete range of bookbinding services to both library binding and commercial customers. We offer three main binding styles: Side-sewn case binding, Otabind layflat adhesive binding, and perfect binding. Complementary capabilities include folding, cutting, drilling, shrink wrapping, laminating and more.
When it simply has to be bound right, make sure it’s Muscle Bound.