What is the Gutter of a Book?

The Gutter refers to the space that runs between two facing pages of an open book. It is the area where the left side pages and the right side pages meet at the spine.

A person holding open a book to display the book's gutter area

A portion of the gutter area is often made unusable by the binding process. When this occurs, the book's inner margins are expanded to compensate for this gutter loss. The degree to which the gutter area is affected largely depends on the type of binding used to create the book.

As mentioned, the inner margins (also known as the gutter margins) may need to be enlarged to prevent important content from becoming hidden in the gutter. That said, let's examine the different binding types to learn how each affects the gutter area…

Perfect Binding

Perfect Binding uses a strong glue to secure a book's pages within a wraparound cover. The glue anchors the pages tightly together at the spine, so any content placed too close to where the binding glue is applied might be difficult to see when the book is being read. This is because the tension created from the firm grip of the glue limits how flat the pages can lie when the book is opened.

A person holding open a thick perfect bound book — *Having ample inner margins prevents important content from becoming buried in a deep gutter*

In addition, the pages of an open perfect bound book will often exhibit some curvature as they radiate out from the spine. This curvature is another reason why text or other content might appear to be "swallowed up" by the gutter. You have likely read books in the past where the text was obscured by the curvature of the pages, requiring you to continually press down on the pages near the center of the book in order to read the content closest to the spine. Needless to say, this leads to a poor reading experience.

The more pages the book has, the greater the potential for content to sink deeper into the gutter and out of view. To compensate for this issue, additional width is often added to the inner margins to help ensure important content is pushed further out from the binding edge so it can be viewed as intended.

A hardcover book lying open on a table — *Expanding the inner margins helps prevent the natural curvature of a book's pages from obscuring content near the gutter*

Hardcover Binding

Depending on the construction method, the pages of hardcover books are either sewn or glued in place (or a combination of sewing and glue). As such, hardcover books will experience the exact same issues as perfect bound books if the inner margins are not ample enough to prevent important content from getting lost in the gutter.

Saddle Stitch Binding

Saddle Stitched books are made from folded sheets that are bound with wire staples placed through the fold line. Unlike perfect binding and hardcover binding, the use of the saddle stitch binding method is limited to books with lower page counts.

A saddle stitched booklet lying open on a table — *Because the pages of a Saddle Stitched book can open fully, no content is lost in the gutter*

Because of the relatively low page count, the spines of saddle-stitched books are thin and do not contain much tension. Hence, the pages can be opened fully. There may be some page curvature but it rarely interferes with content located near the spine.

For aesthetic purposes, saddle stitched books should still have ample margins around blocks of text. However, the inner margins do not have to be widened to the same degree as a perfect bound or hardbound book.

Coil Binding, Wire-O Binding, and Comb Binding

Books created with a Punch and Bind method, such as Coil Binding, Wire-O Binding, or Comb Binding, use preformed spine elements that are inserted through holes or slots punched along one edge of the book's pages and cover.

Unlike perfect binding, hardcover binding, or saddle-stitching, books made with a punch and bind method will have a physical gap between the left side pages and the right side pages when the book is open. Hence, there is zero spinal tension and all of the book's pages will lie perfectly flat.

The spine of a Wire-O bound book — *Books bound with a Punch and Bind method need inner margins wide enough to accommodate the spine element*

Even though the pages lie flat and there are no true gutter or page curvature issues to contend with, the inner margins do have to be wide enough to compensate for the punched holes and spine elements. Because these spines actually penetrate through the face of each page, the plastic or wire spines themselves can obstruct printed content. Therefore, the inner margins have to be wide enough to allow for the placement of the book's spine.

Color Vision specializes in Book Printing!

Color Vision has been producing quality books at affordable prices since 1984. Because we have both digital and offset presses, we can print books in short, medium, or long production runs. We also offer a wide array of printing, binding, and finishing options to help make your book unique.

If you have an upcoming book project and would like to receive a quote by email, please complete our Quote Request form. Or, if you prefer to discuss your project by phone, we can be reached at 800-543-6299.

As always, we hope to hear from you soon and look forward to assisting with your next book project!