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PDF optimization

Courtesy of Kate Bates. Originally posted here:

I found this after hours of frustration trying to find an app that would allow me to reduce scanned documents - it worked perfectly.  I have just copied and pasted the answer for you.

This is a simple and free solution I found to reduce the file size of PDFs in OS X, without the high cost and awful UI of Acrobat Pro, and with acceptable quality. I still use it every day, although I have Acrobat Pro as part of Adove Creative Cloud subscription.

Since quite a few people have found it useful and keep asking questions about the download location and destination of the filters, which have changed since 2007, I decided to write this update, and put it in this more current forum.

Here is how to install it:

Here is the appropriate location for the filters:This assumes that your startup disk's name is "Macintosh HD". If it is different, just replace "Macintosh HD" with the name of your startup disk.

  • If you are running Lion or Mountain Lion (OS X 10.7.x or 10.8.x) then you should put the downloaded filters in "Macintosh HD/Library/PDF Services". This folder should already exist and contain files. Once you put the downloaded filters there, you should have for example one file with the following path:

  • "Macintosh HD/Library/PDF Services/Reduce to 150 dpi average quality - STANDARD COMPRESSION.qfilter"

  • If you are running an earlier vesion of OS X (10.6.x or earlier), then you should put the downloaded filters in "Macintosh HD/Library/Filters" and you should have for example one file with the following path:

  • "Macintosh HD/Library/Filters/Reduce to 150 dpi average quality - STANDARD COMPRESSION.qfilter"

Here is how to use it:

  • Open a PDF file using Apple's Preview app,

  • Choose Export (or Save As if you have on older version of Mac OS X) in the File menu,

  • Choose PDF as a format

  • In the "Quartz Filter" drop-down menu, choose a filter "Reduce to xxx dpi yyy quality";"Reduce to 150 dpi average quality - STANDARD COMPRESSION" is a good trade-off between quality and file size

Here is how it works:

  • These are Quartz filters made with Apple Colorsinc Utility.

  • They do two things:

    • downsample images contained in a PDF to a target density such as 150 dpi,

    • enable JPEG compression for those images with a low or medium setting.

Which files does it work with?It works with most PDF files. However:

  • It will generally work very well on unoptimized files such as scans made with the OS X scanning utility or PDFs produced via OS X printing dialog.

  • It will not further compress well-optimized (comrpessed) files and might create bigger files than the originals,

  • For some files it will create larger files than the originals. This can happen in particular when a PDF file contains other optomizations than image compression. There also seems to be a bug (reported to Apple) where in certain circumstances images in the target PDF are not JPEG compressed.

What to do if it does not work for a file (target PDF is too big or even larger than the original PDF)?

  • First,a good news: since you used a Save As or Export command, the original PDF is untouched.

  • You can try another filter for a smaller size at the expense of quality.

  • The year being 2013, it is now quite easy to send large files through the internetusing Dropbox,, etc. and you can use these services to send your original PDF file.

  • There are other ways of reducing the size of a PDF file, such as apps in the Mac App store, or online services such as the free and simple

What else?

Feel free to use/distribute/package in any way you like.

MacBook Pro with Retina display, OS X Mountain Lion (10.8.2), and other Macs too”


Addendum from original author: "If you need more options to convert PDFs to docs, compress PDFs, etc., I FINALLY found an app that works great - it's made by Wondershare - I bought to PDF converter Pro and it's great.   I don't know why apple doesn't make an app like Adobe Acrobat for Macs - seems so shortsighted!! "

PDF compression filters (Unzip and put in your Library folder).zip
Marion Bates,
Nov 8, 2013, 5:47 AM