Have you looked into Irfanview's [] batch conversion settings and plugins?  Might be something there that is useful.  
Cheers, Paul
Paul R Butler
Assistant Systems Librarian
Simpson Library
University of Mary Washington
1801 College Avenue
Fredericksburg, VA 22401

Sent from the mighty Dell Vostro 230.

-----Original Message-----
From: Code for Libraries [mailto:[log in to unmask]] On Behalf Of Nathan Tallman
Sent: Wednesday, October 24, 2012 10:29 AM
To: [log in to unmask]
Subject: [CODE4LIB] PDF Compression

Can anyone recommend some good PDF compression software? Preferable open-source or low-cost. We're scanning archival collections and the PDFs can be quite large for a single folder. The folder may be thick or thin, and contain a mix of text and images. We've fiddled with various Acrobat settings for getting the file size down, but we haven't found a good balance between quality and file size. (Plus, these need to be OCR'ed; so far we've been doing that in Acrobat.)

We were looking at LuraTech PDF Compressor, but the cost for an enterprise license is pretty high. It did do an excellent job though.