I have a PDF file containing hundreds of BW scannings, that I created on Windows using lossy JBIG2 compression, resulting in a nice 8MB file.

I can open that file on OSX with Preview, but if I add any comment or annotation and save the file, the resulting size is 120MB. If I make the same annotation with Acrobat Reader, the resulting file size is 8MB.

I guess the problem is that Preview saves the BW images using CCITT compression, which has a worse compression ratio. Am I correct? Are there any workarounds for this?

I'm using OS X Mountain Lion, latest update.


The problem appears to be that Preview saves in 1.3 format, which does not support use of JBIG2 (introduced in 1.4). Until Mac upgrades Preview to save as a later version, you won't be able to use JBIG2 compression.


As you have discovered the Preview app can display PDFs that use JBIG2 compression but when the PDFs are exported or saved after changes have been made the JBIG2 compression is replaced with a different compression filter.

Here's an example of a PDF that used JBIG2 compression before and after exporting it in the Preview app.

enter image description here

When you export a PDF from the Preview app you can specify a Quartz Filter. There is one option there called 'Reduce File Size' but this uses a DCTDecode filter instead of JBIG2Decode. It does reduce the file size substantially, but in my testing the quality of image in the PDF after it has been exported is not very good at all.

  • Ok I had it right then. Of course DCTDecode is JPEG, which is not optimized for BW text. Is there a custom quartz filter that would enable Preview to save using JBIG2? I don't want to use Acrobat Reader as it's really slow on my mac. – Pincopallino Apr 18 '13 at 10:21
  • I've done a search on Google but it did not reveal any custom quartz filters which use JBIG2 unfortunately. – Rowan Apr 19 '13 at 0:08

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