Multiple saddle-stitch signatures that are sewn or glued together to make a thicker book. Each signature is a group of nested sheets (just like a Saddle-Stitch Booklet), and the signatures are stacked and bound together.
This is useful for longer documents that would be too thick to saddle-stitch as a single booklet.
In professional bookbinding, virtually all hardback books and many paperbacks are made this way. The pages are printed on large sheets, folded into signatures, and then the signatures are sewn or glued together at the spine, before wrapping a cover around everything. It’s how books have been made for centuries — and it’s one of the reasons books are so durable.
For home printing, multi-signature binding is less common (most people just want a simple stapled booklet). The exception is bookbinding as a craft: if you’re into hand-sewn coptic binding, kettle stitch, or similar techniques, this is the imposition style you want.
Your pages should be in reading order. Octavo splits them into signatures and rearranges the pages within each signature automatically.
The total page count needs to be a multiple of the pages per signature. If it doesn’t divide evenly, Octavo adds blank pages at the end.
Signature breaks are shown in the Page Strip.
How many sheets are in each signature. A larger signature means fewer signatures but thicker folds; a smaller signature means more signatures but each one folds more neatly.
The number of pages per signature is always 4 times the number of sheets (since each sheet holds 4 pages when folded).
Which side of the finished book the spine is on. This determines whether the book opens from the left or the right.