The Best Way to Compress a PDF

by Barrett

Have you had the time to figure out how to squeeze your PDF to the perfect size in OS X? Here’s the good news… Now, you can check this nagging challenge off your ‘boring-tech-fix’ to-do list!

Have you had the time to figure out how to squeeze your PDF to the perfect size in OS X? Here’s the good news… Now, you can check this nagging challenge off your ‘boring-tech-fix’ to-do list!

Pop quiz: When was the last time you scanned a multipage document into a PDF on your home printer/scanner and then realized the file size was too large to use? It happens to me at least once a month… I find it’s often a problem when you want to upload the PDF online, and there are upload file limits.

Okay… so you just have to compress the file. No problem… right?
(Please note touch of sarcasm.)

How to Compress a PDF in ‘Preview’

In the Apple ecosystem, I’ve found the native PDF compression solution remarkably… unintuitive.

That said, here’s how you do it:

Typically, when you click on your PDF, it opens up in ‘Preview.’ From there, you’ve got two choices:

Go to ‘File’ on the top menu bar and look for ‘Export.’

  • Click on ‘Export.’
  • Make sure ‘Format’ is set to ‘PDF.’
  • Then under ‘Quartz Filter,’ choose ‘Reduce File Size.’
  • And then save as you normally would.

Easy… right?
Yes… but the new file that gets created looks… terrible… barely readable. Sure the file is certainly compressed, but if there’s any small text to read, it’s mostly unrecognizable.

The good news is Apple offers a second method…

That’s right… you’re going to ‘print’ your PDF into a compressed file.
(Don’t ask questions!)

Go to ‘File’ on the top bar and look for ‘Print.’

  • Click on ‘Print.’
  • On the bottom left of the ‘Print’ menu, you’ll see a PDF drop-down box.
  • Click on ‘Compress PDF.’
  • Then save as you normally would.

This method creates a larger compressed file than the ‘Export’ route, and as it turns out… the resulting file looks really good.

So if the new PDF is small enough for your needs… you’re done.

For the record, this ‘Print’ method took a 5.7MB five-page PDF down to 1.5MB.
(The ‘Export’ method crunched my file all the way down to a mushy 451KB.)

But what if you want something in between the massive compression of ‘Export/Reduce File Size’ and the heftier PDFs created by ‘Print/Compress PDF?’

Use Adobe Only as a Paid Solution
If you think using Adobe Reader can help you, don’t bother. You’ve got to pay Adobe to help you with compression.
(Adobe Acrobat)

As it turns out, there are other third-party solutions… and some are free. But I’m not interested in MacGyvering this problem. I’m intentionally limiting today’s exercise to the native software that’s already living on my otherwise wonderful Mac.
(There’s got to be a way!)

ColorSync Utility to the Rescue
And, in fact, there is…

The trick is to create a new compression profile using your native ‘ColorSync’ utility. You can duplicate Apple’s standard ‘Reduce File Size’ filter there and easily tinker with the settings of your new filter.

Here’s how:

  • Open ‘ColorSync Utility,’ which typically lives in Applications/Utilities.
  • Click on ‘Reduce File Size.’
  • When you open up ‘Image Sampling’ and ‘Image Compression,’ you’ll see the main profile is all locked up.
  • So click on little upside-down triangle to the right and then click on ‘Duplicate Filter.’
  • This is the step that creates your own personal filter copy. Now you can monkey around to your heart’s content!

Here are the tweaks I added:
(Although there are an almost infinite number of variations you can apply)

  • I increased ‘Scale’ from 50% to 75%.
  • Then, I increased ‘Max Pixels’ from 512 to 1280.
    (I borrowed these setting suggestions from

Voilà… you’ve just created your own custom Quartz filter!

  • Next, simply open up your original PDF with ColorSync.
    (Use the ‘Open With’ drop down.)
  • Go to the bottom left drop-down ‘Filter’ menu.
  • Select your new custom filter.
  • Click ‘Apply.’
  • Save as you normally would.


This new ‘Barrett Compression Setting’ got my 5.7MB PDF down to 900KB…right in the sweet spot between the other two. And the compressed file looked almost as good as the 1.5MB compression…

And that’s all I really needed!

Don’t Forget
So there you have it… two prefab methods and a hidden path to cook up your own compression settings in the OS X environment.

It’s worth noting that much of the online chatter on this topic is years old… so I’m a little late to the party… But on the other hand, what average person is supposed to have this kind of detail readily accessible at their fingertips?
(I hope this post helps.)

In an age where your computer is getting smarter by the minute, shouldn’t a simple compress command with several size settings be readily accessible?

…Just saying.