Spread Defined

A spread is the open two pages of a book. In a normal book, these pages are made from independent leaves that are stitched together at the gutter. A leaf comprises both the front and back of a single page. A loose leaf book has no stitching and is usually held together by a ring binder.

In the case of a pop-up book, each spread is made from a whole sheet of paper, with a fold down the middle (gutter) to accommodate closing the book. Unlike sewn leaf-bound books, the spread of a pop-up book lays flat open, making for one integrated composition across the two pages. The fold is the powerhouse of the mechanics, and relies on solid construction. The leaf of a pop-up book is composed of halves of two opposing spreads glued together in a special way.

All six detached spreads are glued together to form rigid turnable pages. A leaf is essentially formed when the adjacent half of a pop-up spread is glued to its mate.