PDF Labs

You scanned a two-sided document by first scanning all the odd pages and then scanning all the even pages. Now you have two PDFs: one of odd pages and one of even pages. And the even pages are in reverse order! How can you collate these pages into a single, right-reading document? These instructions will show you how to do this with our command-line tool PDFtk Server.

PDFtk Server is free (as in freedom) software that you can use to manipulate PDF documents. You can download free installers for Windows and Mac OS X from our site. Most Linux distributions maintain a "pdftk" binary package you can install.

PDFtk has a special feature that we added specifically to solve this problem of arranging scanned pages: shuffle. Say you have two PDFs: even_pages.pdf and odd_pages.pdf. Then you can collate them into a single document like this:

pdftk A=odd_pages.pdf B=even_pages.pdf shuffle A B output collated_pages.pdf

If your even pages are in reverse order, you can reverse its page range:

pdftk A=odd_pages.pdf B=even_pages.pdf shuffle A Bend-1 output collated_pages.pdf

The shuffle feature works by taking one page at a time from each of the input page ranges and assembling them into a new PDF. You specify these ranges after the shuffle keyword, and you can have more than two ranges. Our PDFtk Server manual explains how to describe page ranges — they are very flexible.

Shuffling can be used for other jobs, too.

Say you have a 1500-page PDF print job and you need to place a single-page PDF on the ‘back’ of each of these pages so that the final PDF print job is 3000 pages. First, turn the single-page ‘back’ into a 1500-page PDF. The following example isn’t the most elegant, but it illustrates the method:

pdftk A=back_page.pdf cat A A A A A A A A A A output back_x10.pdf

pdftk A=back_x10.pdf cat A A A A A A A A A A output back_x100.pdf

pdftk A=back_x100.pdf cat A A A A A output back_x500.pdf

pdftk A=back_x500.pdf cat A A A output back_x1500.pdf

Next, collate the print job ‘fronts’ with the ‘backs’:

pdftk A=fronts.pdf B=back_x1500.pdf shuffle A B output print_job.pdf

Finally, sometimes you want to go the other direction and extract the even or odd pages from a PDF. You can combine them again using shuffle, later. You might do this if you wanted to apply a stamp to just the even pages of a PDF, for example.

Extract the even pages:

pdftk A=full_doc.pdf cat Aeven output even_pages.pdf

Extract the odd pages:

pdftk A=full_doc.pdf cat Aodd output odd_pages.pdf

Article Author: Sid Steward