Scanned PDFs are the biggest offenders when it comes to file size. A typical flatbed scan produces 300 DPI images, and a 10-page document can easily reach 50MB or more. This makes them impossible to email and slow to upload.
Why Scanned PDFs Are So Large
Each page is a full-color, high-resolution image. Unlike digital PDFs where text is stored as compact character data (a few KB), scanned pages store every pixel — millions of them per page.
Compression Results
Scanned PDFs respond dramatically to compression because there's so much image data to optimize. Using FreePDFNest Compress PDF:
Low compression: 30-40% reduction. Virtually no visible difference.
Medium compression: 50-70% reduction. Text remains readable, photos slightly softer.
High compression: 70-90% reduction. Text still readable, images noticeably compressed but functional.
A 50MB scanned document at high compression might shrink to 5-8MB — well within email limits.
Additional Tips
Scan at lower DPI: If you haven't scanned yet, 150-200 DPI is sufficient for documents that will only be viewed on screen. 300 DPI is only needed for professional printing.
Scan in grayscale: If the document is black and white text, scan in grayscale instead of color. This reduces file size by about 60% before any compression.
Ready to try it?
Use our free Compress PDF tool — no signup required.