The file size of PDFs can become quite large, especially when scanning documents or documents containing images. Instead of sending large files, it is almost always recommended to reduce the file size. To do that, there are several ways. For example, there is an app called PDF Squeezer in the Mac App Store (€3.59 or $3.99).

The same functionality can be achieved using Quartz filters in the ColorSync Utility. There is already one called “Reduce File Size” but it might lead to a blurry PDF. You can copy this filter and adjust the settings. However, I found custom filters in the Apple Support Community that work quite well.

  • Download the filters and unpack them.
  • Move the filters to ~/Library/Filters
  • Open your PDF with ColorSync Utility
  • In the bottom, choose the appropriate filter. There are several options starting with Reduce to …
  • Click Apply
  • If you are satisfied with the result, save the file under a different file name (File > Save As).