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A simple and free way of reducing PDF file size using Preview

39168 Views 45 Replies Latest reply: Apr 7, 2014 4:09 PM by Pepetono RSS
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Jerome Colas Level 2 Level 2 (215 points)
Currently Being Moderated
Apr 16, 2013 9:35 AM

Note: this is a copy and update of a 5 year old discussion in the Mac OS X 10.5 Leopard discussions which you can find here: https://discussions.apple.com/message/6109398#6109398

 

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 internet using Dropbox, yousendit.com, wetransfer.com 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 http://smallpdf.com

 

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
  • nmann Level 1 Level 1 (0 points)

    Thank you for the update, being able to do this made me feel a little bit smarter & saved a ton of time!

  • SKY DRIVER Level 1 Level 1 (0 points)

    Great job-works fine--much thanks!

  • ioscar Level 1 Level 1 (0 points)

    I'm having difficulties downloading the filters. Dropbox says:

    Error (509)

    This account's public links are generating too much traffic and have been temporarily disabled!

    Good news, cause this means the filters are popular. Or are you hosting some other... Is there any other site available? Thanks Jerome!

     

    Edit:

    Nevermind, I found the filters in this blog posting. Thanks again.

  • Dannymac22 Level 1 Level 1 (0 points)

    I've been looking for reliable ways to compress pdf. Quartz filters are one way to do it, but it has always troubled me that the results are often unpredictable. I've used these Quartz compresson strategies to reduce the size of many pdf documents. While a lot get smaller (yay!), some get bigger (oh, crap!). Much bigger! Never had any explanation for that. What I think is going on is that Quartz doesn't do jpeg compression, but rather a compression strategy that is more appropropriate for text and line drawings. So if you have a document with a lot of jpeg images in them, this compression strategy probably won't work. It certainly won't work for pdfs that are basically made of jpeg images, such as what you get when your document was produced by most scanning routines, including the ubiquitous VueScan.

     

    All pdf documents aren't created equal, and compression really should be a rule-based strategy as in, if you have this kind of document, do this, but if you have that kind, do that. Would be nice if someone knowledgable would weigh in on that.

     

    I like smallpdf.com very much, and it works great on jpegs, but since the application is remotely based, you're basically shipping your document off to someone else to get it compressed. One has to wonder about data mining, in that case.

  • phil.c Level 1 Level 1 (0 points)

    I am trying to understand a strange case.

    I had a 48 page ppt file converted to pdf that took 4.5MB, so far so good.

    I cut the first 23 pages away with preview and I get a file with the last 25 pages but the size is now 19.4MB

    I try to reduce its size with the standard "reduce file size filter" and, low and behold, I get a 280MB file, yes the size is multiplied by 15 more or less.

    Desperately trying to reduce the size, I came accross this thread, downloaded the filters tried with the standard recommended filter and same result 280MB... OK, let's give up on quality and choose the 75dpi, low quality option, result is still 279.2MB!

    Does anyone have a clue of what causes this file of reasonable size to blow up out of proportions!

     

    Thank you very much for any help!

     

    Philippe

  • Dannymac22 Level 1 Level 1 (0 points)

    Think that pretty much exemplifies the issue here. I've had exactly the same experience.

     

    My experience with these and other Quartz filters for pdf file compression is basically flip-the-dice, cross-your-fingers, and say a prayer. They might work well, but they might work horribly. As I mentioned, as a free option, smallpdf.com has never failed me, though it involves sending your document to someone else.

     

    I've used the limited-time trials of several of the commercial pdf compressionsoftware, and they also work marvelously. So you get what you pay for, in those cases.

     

    I think what it means is that writing pdf in Preview isn't smart, if you want to conserve or reduce file size.

    I wish I knew why that was the case.

  • Ian Jelinek Level 1 Level 1 (5 points)

    Thank you for your service to us, sir!

  • asballard Level 1 Level 1 (0 points)

    Jerome - I'm having trouble with this part:

    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"

     

    I've DL the filters and it's just a folder with the "filter"s saved as a document?  I'm not sure where to save them from here or how?  Could you please walk me thru this?  Thank you!  I have Moutain Lion 10.8.3 and I'm not sure where to find the Library/PDF Services file?

  • ipsyd Level 1 Level 1 (85 points)

    In recent versions of OS X, the Library folder is hidden. To get into it, first make sure you're in the Finder. Hold down the Option key, then click the Go menu. Hey presto! There in the middle of the menu is the Library folder Jerome is referring to. Everthing else in his excellent instructions should now be straightforward...

  • actionmarker Level 3 Level 3 (875 points)

    Hi Jerome,

     

    I respect that you have spent a lot of time setting this up, but why not just use Automator App (in the Applications folder) to do the same thing?

     

    Create a workflow, to load the PDF, you can load one PDF or can even combine multiple PDFs, Compress the images in the files to a variety of qualities and then either open or save the new compressed file.

     

    I'm not saying what you are doing is incorrect, but it seems to me that this funtionality is already built into OSX. I use it all the time  for my University assignments, before I submit, as the uni has strict upload limits.

    I works flawlessly for me, with documents from Word, Pages, Excel, Numbers, PowerPoint, Keynote, and Scanned documents too.

     

    A

  • asballard Level 1 Level 1 (0 points)

    Jerome - thank you SO much for spelling this out for me!!  It was very easy once going through step - by step.  Also thanks to ipsyd - that shortcut to the Library totally worked!  I'm so excited to downsize my massive real estate contract! haha  actionmaker - I did try the workflow in automater, but couldn't figure it out... migth need a step-by-step there too   Thanks to all for all your help!  Now.... if I could just figure out how to send property pictures to my office admi via the Mac Mail assistant WITHOUT it being embedded in the body of the email... ;0]

  • Newt4 Level 1 Level 1 (0 points)

    asballard if you're saying you want PDFs in your emails to appear as small icons instead of full blown PDFs, I can help you with that.

    Open your email, attach your PDF in the body, select the PDF, right click.

    From the menu selections choose 'view as icon'.

    Voila! the PDF should now appear as a tidy PDF icon. I just tried the same trick with a photograph (jpg) and that works also.

    Patti

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