Book Binding 101

Book Binding 101

-Written by: Shawne

Books are amazing things. They can transport you to another reality, bring a smile to your face, and tell stories of heroes, villains, and far off places.

So to cover this, let’s have a look at the process of binding a book, so that you can better understand the issues. For this discussion, we’re going to focus specifically on softcover books. Hardcover books are bound in a slightly different manner, and because of their cover attachment do not have the types of concerns that standard paperbacks encounter.

How a Book is Created

Books are made in several steps. Once the book is delivered to the printer, the first process is the printing itself. All of the pages are assembled into a printing plate in groups called signatures. Depending on the printer, these signatures might be in groups of 16, 32, or 64 pages.

Signatures are designed such that when printed and folded up, the pages themselves will be in the proper order. A book will have multiple signatures. Sometimes, you’ll find that a book has some blank pages at the front or the end. That’s because the number of pages didn’t fit the types of signatures used and there were extra pages needed to support the printing.

Once the printing is complete, all of the various signatures are gathered together and placed into a bindery machine. Generally, there are inserters that are set in the correct order to continuously feed each signature into the machine.

All of the signatures for the book are then collated together, so that all of the pages are in order for the book. They are clamped together and moved forward.

The signatures are pulled from the top bins and are being collated together (Finishbinders., Inc. of Des Moines, IA).

Bindery begins where first there is a trim (called “spine milling”) that is made to rough up the spine-edge of the collated signatures.

Hot glue is put on the milled spine, and then the cover is wrapped around the group of signatures. This leaves a book that is still filled with folded signatures and a cover that is oversized.

Covers are brought in and the interior pages, which have had glue attached, are inserted inside. The covers are then folded over the book and head to the trimmer (Finishbinders., Inc. of Des Moines, IA).

The book then moves along to the trimmer, where it is trimmed down to its final size. It then leaves the bindery machine to be boxed into master cartons for shipment.

Books headed to the trimmer (Finishbinders., Inc. of Des Moines, IA).

Trimming process, books then pulled up to be quality checked and then put into the final master cartons (Finishbinders., Inc. of Des Moines, IA).

Issues with Books

Rarely, errors in the process of making the printing plates can create flawed books. For example, if the printing plate was not made properly, there can be excess ink on the page that is blotchy or blemished. In general, press checks at the time of printing expose these problems and the batch is discarded.


One error you might encounter is a book where one of the signatures was inserted in the wrong order, meaning the pages are out of order, duplicated, or upside down. We will certainly exchange any book where this might occur.

A glue error may be where too much or not enough glue was applied to attach the signatures into the spine. Most books with this error are caught when the books are put in the master carton. You might see the spine have a ripple or smush at the bottom. Even though this is a flaw, it’s not generally rejected by publishers as the book is perfectly usable. We do try to reject these on our own if we see them at delivery. If the issue is severe and it gets to you, we will look to exchange the book. If there wasn’t enough glue used, the pages can separate from the cover, which is of course a problem.


The most common issue we see is trim tears. Books move very rapidly through the bindery machine, and very large cutting blades are used to trim the books. Should these blades not be sharp enough, or if there is some excess glue which catches on them during the process, a small tear might occur at the base of the spine. The faster the trim machine is moving, the more likely the spine trim knives are not being resharpened or replaced as frequently, and this can affect many, or even a whole run of books. This is not considered in the printing industry to be a defect and these books are not rejected. As it is so common, we will not exchange books with this as it’s likely the entire batch we received will have similar issues because they would have been made at the same time.


Another issue we see periodically is slight delamination at the trim points, where part of the cover lamination was torn or scuffed. As above, generally this is due to the trim knives getting caught on the edges of the glue section and is not considered to be a defect.

Finally, if the trimmer is just set wrong, the book isn’t trimmed either to the right size (under or over trimmed) or becomes an odd shape. It’s incredibly rare to see this get by a quality control person, but we have received some this way. These would almost be a collector’s item – but of course if we miss it all the way to you we will definitely replace it.


In a perfect world, all books would of course be perfect, but as there are mechanical processes used to create the books, and humans used to review them, it’s not always the case. We do what we can to ship books in the best condition possible, and hope that this post will help you to better understand the process and its limitations. Happy reading!

Special thanks to Finishbinders, Inc. of Des Moines, Iowa for the videos of their book binding process.

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