How to fix a blurry scanned PDF

A blurry scan is hard to fully fix — you cannot add detail that was never captured — but you can avoid making it worse and improve legibility.

Rescan if you can

The real fix is a better scan: 300 DPI, flat original, good light. Software cannot recover detail the scanner missed.

Do not re-compress hard

Heavy JPEG compression adds its own fuzz. Keep quality high when saving a scan you care about.

Boost contrast

Increasing contrast can make faint text more legible even if it is soft.