How to compress a PDF on a Mac.
Preview can do it — badly. Here's the full picture.
Preview ships a 'Reduce File Size' filter that is famous for turning readable scans into 72-dpi mush. It works; it just has one setting, and that setting is 'potato'. The methods, honestly ranked:
1Preview's Quartz filter (built in — crude)
- Open the PDF, File → Export…
- Set Quartz Filter to 'Reduce File Size'.
- Save and inspect the damage.
Dramatic size cuts, frequently unreadable results on scans. Fine for text-only documents that were barely big anyway.
2Custom Quartz filter (built in — better, hidden)
- Open ColorSync Utility → Filters, duplicate 'Reduce File Size'.
- Raise the image resolution and quality values in the copy.
- Use the custom filter from Preview's export dialog.
The pro-forum fix. Works, survives exactly until you forget how you did it.
3Rename with RenameTo
- Rename deck.pdf to deck.small.pdf, press Return.
- Images inside the PDF are re-encoded sensibly; text stays selectable.
- Need a hard ceiling? deck.10mb.pdf targets a size.
Tuned defaults, no ColorSync spelunking, with the original backed up first.
small compresses the images inside the PDF while leaving the text layer alone — the balance Preview's filter never found. And the size-target commands work on PDFs too.
Questions? Answers.
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