Open Source command line tool for optimizing PDF

Solution 1:

I'll quote zweifel's comment on http://www.ubuntugeek.com/ubuntu-tiphowto-reduce-adobe-acrobat-file-size-from-command-line.html:

• dPDFSETTINGS=/screen (screen-view-only quality, 72 dpi images)
• dPDFSETTINGS=/ebook (low quality, 150 dpi images)
• dPDFSETTINGS=/printer (high quality, 300 dpi images)
• dPDFSETTINGS=/prepress (high quality, color preserving, 300 dpi imgs)
• dPDFSETTINGS=/default (almost identical to /screen)

More options and fine tunning on the site: http://milan.kupcevic.net/ghostscript-ps-pdf/

Thus you should use either the option dPDFSETTINGS=/printer or the option dPDFSETTINGS=/prepress to get 300 dpi.