Saddle Stitch Imposition Glossary

Printing has its own vocabulary, and the tool and guides use a handful of these words a lot. Each entry below explains what the term means and how it shows up when you make a booklet with Booklet Imposer.

Saddle stitch

A way of binding a booklet: printed sheets are nested inside each other, folded once down the middle, and stapled through the fold. The name comes from the saddle-shaped support that binding machines use to hold the open sheets. It suits short documents such as zines, programs, and handouts. See what is saddle stitch.

Imposition

Arranging pages on printer sheets so they end up in the right order after folding. A normal PDF runs 1, 2, 3…, but a booklet sheet might carry pages 8 and 1 side by side. Imposition is the job this tool does for you. The rules are explained in how to impose a PDF for saddle stitch.

Reader page

A page as a reader sees it in the finished booklet: page 1 is the cover, page 2 is the inside cover, and so on. Your source PDF is numbered in reader order. Any blank pages the tool adds are numbered too, at the end.

Sheet

One physical piece of paper. Every sheet has a front and a back, and each side holds two reader pages, so one sheet makes four pages of the booklet. An 8-page booklet uses two sheets; a 16-page booklet uses four.

Signature

A group of sheets that are folded together as one unit. Books with hundreds of pages are made of many signatures sewn or glued together. A saddle-stitched booklet is a single signature: all the sheets nest and fold at once, which is the only layout this tool produces.

2-up

Two pages printed side by side on one side of a sheet. Booklet sheets are 2-up with the fold running between the two pages. That is why an A5 booklet is usually printed on A4 paper, and a half-letter booklet on US Letter.

Page order

The sequence of pages on each sheet. For a booklet with N pages, the outer sheet carries N and 1 on the front, then 2 and N−1 on the back; each sheet further in continues the pattern. The page order calculator shows the order for your own file.

Creep (shingling)

When a stack of sheets is folded, the inner sheets stick out slightly further at the open edge than the outer ones, because they wrap around less paper. After trimming, their margins can look narrower. Creep compensation shifts the content on inner sheets toward the fold to even this out. See gutter vs creep.

Gutter

Extra blank space added on the fold side of every page, so text and images don’t disappear into the staples or the curve of the spine. In this tool the gutter value is added to each side of the fold. A few millimeters is usually enough for thin booklets.

Bleed

Artwork that extends past the final trimmed edge, so there is no thin white line if the cut is slightly off. If your PDF was designed with bleed, enter its size in the tool so it knows where the real page edge is. If you won’t be trimming, leave it at zero.

Trim

The finished size of a page after any excess paper is cut away. Crop marks, if you turn them on, show where to cut. Many home-printed booklets aren’t trimmed at all, and that is fine.

Spread

Two pages you see together when the booklet is open, such as pages 2 and 3. The closed booklet’s cover and back cover also form a spread (the last page next to page 1). The tool’s Spreads view shows your booklet this way so you can check the reading order.

Duplex

Printing on both sides of the paper. Many home and office printers can do it automatically. Booklets need duplex, either automatic or by feeding the sheets through a second time by hand.

Short-edge and long-edge flip

The two ways a duplex printer can turn a sheet over before printing the back. For booklet sheets, with two pages side by side on landscape paper, choose flip on short edge so the back comes out upright. Driver wording varies, so check with one test sheet. The double-sided printing guide has a diagram.

The tool arranges page layout only. It doesn’t change colors, and interactive features such as links or form fields are not kept in the exported file.