Wow! I just discovered a little tool that does exactly what I’ve been looking for since ages. I’m sure you’ve also wondered about this after having scanned a book or book chapter: how can I cut those scanned double pages down the middle and make two pages out of it (because it is two pages in the book)? And, of course, you want to do it automatically. If you’re using Adobe Acrobat, you might expect that this rather expensive software has that function built in, but you will find: it hasn’t.
But thanks to Gerhard Aigner, you wont have to worry about this any more because he created Briss, a cross-platform (Linux, Windows, Mac) java-application for cropping .pdf-files. Oh, and did I mention that it is freeware? You just open your pdf file, position the rectangles according to the position of the pages in the book and select “crop pdf”.
My only criticism (or suggestion for improvement) would be the following: while the program allows you to copy cropping frames across different sections of the document, it does apparently not allow you to copy the frame for the odd pages and use it for the even pages. So if you want to have odd and even pages in the same size and format, you need to draw your even-pages-frame on top of your odd-pages-frame to make sure they are the same size (only visual judgement!) and then drag it over to the even page. It’s feasible but a bit cumbersome. Or well, actually, it can be almost infeasible at times, namely when your frame as exactly the height of the page, because the the size of a frame changes if you move it across the edges of the page and since you will hardly be able to move your mouse 100 percent horizontally, the frame will get smaller as you drag it.
Oh, and drag’n'drop would be nice: i.e. the possibility to drag your pdf into briss directly from Windows Explorer. And an option “First page last”. The latter would facilitate scanning of brochures and booklets because in those the first scanned page will contain the front cover and the back cover.
Another think to be aware of is that the briss (just like Adobe Acrobat) apparently does not delete the parts of the pdf that are “cut off” but just makes them invisible. At least that’s what I gather from a comment by user “Viking2ev” on sourceforge. But that’s only a problem if you want to get rid of confidential information.
Oh, and irrespective of briss, during scanning, you need to watch that your book in the same position on the scanner for every double page. Otherwise you might have to do several runs with briss and then merge the files back into one with Acrobat or so.
Having said all that, I still think that briss is an excellent tool for scholars to use. Just go and try it out.
[UPDATE: I just found a very similar program that seems to be more flexible to use: It's called Scan Tailor, it's also Freeware and it seems to be maintained better as the last update is from May 2012 while Briss hasn't been updated since July 2011). The only (big!) problem is that it is apparently unable to read .pdf-files. So your scans have to be in supported files types are .tif, .tiff, .png, .jpg, .jpeg ... So if that is okay for you, try both and tell us what you think about them in the comments below!]