Until a couple of hours ago, I’d never heard of PDFClerk Pro. But some website or other (dealmac?) alerted me to a bargain price for it on MacUpdate. I downloaded it, tried it out, and sprang for the $25 price after about 20 minutes’ worth of fiddling.

Why? After all, I’m a Mac fanboi. And one of the many benefits of working on a Mac is that it comes with Preview, which allows you to do 95% of what you might want to do with PDFs: reorder pages, combine pages from multiple files, etc. I use Preview’s PDF-editing features 10-20 times a week, if not more. So why do I need PDF Clerk Pro?

But there are some things it won’t do, and imposition is one of them. Imposition is rearranging pages so they’re in the proper order for printing and binding a document. For example, a pamphlet with 8 pages can be printed 2-up, but then page 1 appears on the back cover, page 2 on the front, 3 on the inside front, 4 on page 1, etc. Imposition reorders the pages thus: 8-1-2-7, 3-4-5-6. If you print that 2-up, then it comes out right for stapling. See the link if I’m not being clear.

The other thing Preview won’t do is let you crop pages. (Well, just barely.) When you print pages 2-up on 8½” × 11″ paper, you realize that its aspect ratio (0.77) is not the same as that of a 5½” × 8½” half page (0.64). So you wind up with a white band above and below your scaled down original pages. That’s how you fit a 0.77 A/R box into a 0.64 box.

But almost all the time, your original letter-sized document has margins, and margins change things. If you use 1″ margins, then your letter paper has an effective size of 6½” × 9″ and an aspect ratio of 0.72. That’s a lot closer to 0.64 than 0.77 is. So it would be nice if 2-up paginators were smart enough to ignore the white space on your document. But since they aren’t, it would be nice to be able to crop pages manually.

MacOS X’s Preview application lets you crop pages, but won’t do imposition. Enter PDF Clerk Pro, which does both.

To be sure, PDF Clerk Pro has a really ugly user interface. I’ve seen native Java apps on Windows that look prettier. But pretty isn’t always everything. If you need to do imposition or fiddling with bounding boxes in PDF documents, then PDF Clerk Pro may be what you need.