Unfortunately, elements in the document can balloon a PDF's size, which can make it difficult to upload and download files. In an effort to fix the issue, most people resort to compressing the PDF file. However, this potentially degrades the file's quality.

How do I reduce the size of a PDF without losing quality?

Open your PDF file in Preview. It should be the default option, but in case it isn't, Right Click on the PDF file, select Open with > Preview. Then, click File > Export, and in the Quartz Filter drop-down box, select Reduce File Size. The software will automatically reduce the size of the PDF file.

What happens when you compress a PDF?

For images and other graphic materials (like PDF files), this means a recreation of the original at a smaller resolution (fewer pixels). Furthermore, once a file is compressed, you may not be able to return it to its original state (unless you keep a backup).