Mac OS X 10.6: Compressing a PDF file
Large PDF files can be difficult to archive or email. Using Preview, you can compress a PDF file so it’s easier to share or store.
To compress a PDF file:
Open Preview, in your Applications folder.
Choose File > Open, select the PDF file to compress, and then click Open.
Choose File > Save As, choose Reduce File Size from the Quartz Filter pop-up menu, and choose a name and location for the new PDF file.
This process compresses the images in the file. The compressed images look the same as the originals when viewed onscreen, but may appear to be of lower quality when printed.
You can save any document as a compressed PDF file. For more information, see: