I have a 352 page pdf that is a scan of a black-and-white text. The file size is 60.9 MB, which seems excessively large too me. (Is it indeed?)

Is there an easy way to convert this file to a more compressed one?

Edit. Here's a little sample:

enter image description here

4 Answers 4


60MB is probably OK for a greyscale scan of 350 pages. I have some 100pg color scans that clock around 30MB. If you meant it's actually black and white (and no grey) then it's definitely too big.

Preview is probably a bad tool to try to get the file size down without hurting image quality. The only tools available will resample the image to a lower resolution. What I use in a case like this is Acrobat Pro, which will let me convert the compression of the embedded scans to JPEG2000, which can save a lot of space over normal JPEG and retain quality.

  • Given the limited use I intend to make of it, I find USD 299 a bit steep. :) But thanks for the other information.
    – Řídící
    Oct 26, 2013 at 16:35
  • 1
    There's a 30-day trial of Adobe apps, with Acrobat at adobe.com/cfusion/tdrc/… . If you have a short-term need to shrink a few files, this would be a good route. Oct 26, 2013 at 16:53
  • That is one big application. So, I did Save As Other... > Reduced Size PDF > Adobe 10.0.0, (I assume this is what you meant with JPEG2000?) and... waiting... down to 15.9 MB and sharp as before! Great. Many thanks.
    – Řídící
    Oct 26, 2013 at 17:27

A great PDF compressor is Ghostscript (gs), which is native in most Linux distributions and easily installable for Mac OS X and Windows.

Daniel summarizes it best here, with the key quote being his preferred options:

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dNOPAUSE -dQUIET -dBATCH \
    -sOutputFile=foo-compressed.pdf foo.pdf
  • 1
    This worked great. brew install gs did the trick and got a 3MB pdf down to 940K. Still looks great. Nov 29, 2017 at 3:08

If it is just text and no images, it is indeed quite large.

There are several ways to compress the PDF file, and one of them is a simple solution with Preview.app:

  • Open the file in Preview.app
  • Go to the File > Export... menu option
  • Provide a name for the file
  • Below in the Quartz Filter: dropdown, choose Reduce File Size (the default would be "None")
  • Click Save

If the result is a well compressed file but the readability is negatively impacted, you can try scanning at a much higher DPI and compressing it (to get a better compromise between file size and readability) or use a third party product to do OCR on the file (PDFPen, PDFScanner, VueScan and ABBYY FineReader are just some of the several options available).

  • 1
    Thanks, I followed your suggestion and indeed it went from 60.9 to 23.1 MB. However, the text became fuzzy, virtually unreadable. :(
    – Řídící
    Oct 26, 2013 at 12:54
  • That's one of the gambles with any image compression. You would have to scan it at a higher DPI and then compress it to get a better compromise between file size and legibility.
    – M K
    Oct 26, 2013 at 13:07
  • VueScan has a free demo. Not quite sure how to go about going from pdf to pdf. (Rescanning the paper is a psychological no-no.)
    – Řídící
    Oct 26, 2013 at 13:22

Found this online tool, it compressed my 100 MB b&w pdf to 18 MB using the medium setting, quality is still very acceptable for reading.


It may be a problem if the user has restricted bandwidth as the file has to uploaded and re-downloaded, Dropbox or Google Drive integration is also offered as an alternative but I have not tested it.

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