PDF booklet

How to use it

Load the PDF, choose the size of the sheet you will print on and press «Build the booklet PDF». You get back a new PDF made of landscape sheets, each holding two pages side by side, already in the right order. Print it double sided, fold the whole stack in half, put two staples on the fold and the booklet is done. The diagram at the bottom of the page shows, sheet by sheet, which page numbers land on the left and on the right of the front and of the back, so you can check the result before you even open the file.

Why the page order looks wrong when it is right

When you fold a sheet in half, the right half of its front becomes the first page and the left half becomes the last one. In an 8 page booklet the first sheet therefore carries 8 and 1 on the front and 2 and 7 on the back, the second one 6 and 3 on the front and 4 and 5 on the back. The general rule is the pair (n, 1), then (2, n minus 1), then (n minus 2, 3) and so on towards the centre. Since every folded sheet always produces four pages, the total is raised to the next multiple of four by adding blank pages at the end, where they get in the way the least. This is the arithmetic that hardly ever works out by hand, and that free PDF readers do not do.

Double sided flipping, which is where printing goes wrong

Double sided printing can turn the sheet around its long edge or around its short edge. A landscape sheet folded in the middle needs short edge flipping, otherwise the backs come out upside down against the fronts. If your printer only flips on the long edge, pick that entry in the menu: the back sides are then turned by half a turn inside the file and the result works out. With no automatic duplex, choose «All fronts first, then the backs», print the first half, put the stack back in the tray and print the second one. In every case a test with a single sheet pays for itself, because every printer has its own feeding direction.

Sheets per signature, margins and fold

Beyond five or six sheets folded together the booklet fans open, the innermost pages stick out and desk staplers no longer reach through the stack. For a long booklet it is better to print several signatures of 4, 5 or 8 sheets and gather them: the «Sheets per signature» menu recomputes the order for each group. The outer margin is there for the printer, which cannot reach the edge of the paper, while the space towards the fold keeps the text away from the stitching. One thing this tool does not do: it does not compensate for creep, the few millimetres by which inner pages stick out and which careful print shops trim off.

What is left out, and where your files stay

The booklet holds the page as it prints. Clickable links, form fields, comments and bookmarks are not carried over, and a password protected PDF has to be unlocked first. Rotated pages are set straight the way you see them on screen, and pages of different sizes are fitted one by one to their half sheet, so in a mixed document the scale is not the same for all of them. The limit here is one thousand pages. All the work happens inside your browser with a PDF library loaded together with the page: the file is never sent to a server, and you can go offline before opening it.