Reducing the file size of a PDF can be useful in many instances, but especially when you’re sending a PDF by email and are faced with limitations on the size of attachments. These days it’s safe to assume that a file of 10 MBs or less will not have trouble making it to an email recipient, but the best practice is to reduce the file size of a PDF as much as possible before sending it via email.
To reduce the file size of a PDF go to the FILE menu and choose SAVE AS and then you’ll see the choice REDUCED SIZE PDF… as depicted in the screenshot below (click on any screenshot to enlarge it):
The menu choices described above work in Adobe Acrobat X and higher. In earlier versions the option could be selected much more easily, by simply choosing FILE > REDUCE FILE SIZE.
After you’ve chosen to reduce the file size you’ll be presented with a dialogue box like the one below, which asks you to specify how compatible you want the resulting file to be.
That is, do you want the file to be compatible with very old version of Acrobat, or only the more recent versions. If you select the default, which is “retain existing,” then the compatibility of the PDF will be retained. What’s the current compatibility? There’s no easy way to tell, and so I wouldn’t fret about it. Just leave it on the default setting and see how much smaller the file size turns out to be.
To determine how much reduction took place you need to ascertain the file size before you perform the reduction, and then measure it after you reduce. To examine File Size of the current PDF go to the menu FILE > PROPERTIES and then you’ll be presented with the dialogue box below:
Note the file size before you do the reduction, and then go back and check after you’ve done the reduction. In fact, I’d recommend learning the keyboard command to quickly take you to this dialogue box. On a Windows computer it’s CONTROL + D, and on a Mac it’s COMMAND + D.
That dialogue box also allows you to view security settings, and define the Initial View of the PDF, both very useful things to know how to do.