The unix program 'unpaper' was recently recommended for cleaning up artifacts on scanned images. Unfortunately it doesn't natively do pdfs, only "pnm family" -- pbm, pgm and ppm formats. [more inside]
posted by acro on May 16, 2007 - 10 answers

How do I take 5 pdf files and combine them into one file without Acrobat? [more inside]
posted by photoslob on Apr 29, 2007 - 7 answers

How can I scan a book that is precious to me? The book is a couple hundred pages and I just want to produce high-quality pdfs. [more inside]
posted by vacapinta on Oct 25, 2006 - 9 answers

Graphically editing multi-page PDFs quickly (erasing things, mostly) [more inside]
posted by anonymoose on Oct 18, 2006 - 8 answers

I need to convert a scanned pdf to searchable text, without printing it out and scanning it back in using OCR. Also, I'd like a cheap or free solution since I'm not likely to use it often ever again.
posted by nomis on May 6, 2004 - 17 answers