Updated April 13th, 2020.
Sometimes you have a PDF that you want to compress, usually because you want to email it and you know it’s too big to send. Here’s an easy way to do it, and it uses Apple’s Preview program, something that comes with every Mac. (If Acrobat opens when you double-click a PDF, try Control-clicking on a PDF’s icon and then choosing “Open With…” and then “Preview.”)
Here’s the Get Info box for the Keynote ’09 Manual (you know: click on the icon once, then File/Get Info). You can see the size (boxed in red): 13.8 megabytes. That’s too big to email, so you need to compress it. Turns out it’s really easy to do.
Get your document open in Preview, then choose Save As… from Preview’s File menu.
UPDATE: In Mac OS X Lion, Preview’s File menu doesn’t have a Save As… command! It does have an Export… command, and that’s what you’ll choose in Lion. Everything else is the same.
You’ll get this box:
(If you don’t see a box this big, click the triangle (boxed in blue here) to expand it.) Notice the “Quartz Filter: Reduce File Size” (boxed in red). You have to choose that. Ordinarily, it says “Quartz Filter: None.” Change it to say “Quartz Filter: Reduce File Size.” Below: the other choices, in case you’re interested. I don’t think I’ve ever used any of them. Experiment if you’d like but for our purposes here, use “Reduce File Size.”
You should give your reduced-size PDF a new name before clicking “Save” because you will want to be able to compare the reduced one to the original. You don’t want to over-write the original. At least I don’t think you do.
In this example, I got info on the reduced-size PDF and looky how much smaller it is:
The reduced-size version is less than 25% as big as the original. That’s great. This one, we can email.
Of course, before emailing it we want to check the quality. Here are some screen shots showing you the original and the reduced-size versions (look in the title bars– the smaller one says “smaller”).
Virtually identical. However, compression is not always so neat and clean. In some cases the quality will not be very good after being compressed. But, a lot of times it will be, and since Preview is right there on your Mac already, it is certainly worth a try.
UPDATE: I just learned, thanks to an article on Macworld.com, that you can adjust the amount of compression performed by the “Smaller PDF” filter, which means you can adjust the quality too. What a great thing. Here’s the link to the Macworld article.