Why Scanned PDFs Are Heavy and How to Lighten Them
Key points
- Scanned PDFs consist of high-resolution page images
- Compression can usually shrink them a lot
- Adjusting scan settings makes future files lighter
A PDF scanned on a printer can reach several MB per page.
Why it is heavy
A scanned PDF page is a high-resolution image. Scanning in color and at high resolution (such as 600 dpi) makes it bigger.
How to lighten it
- In "Compress PDF", set a size limit or compress at "Normal" quality. Image-based PDFs shrink a lot.
- Delete blank pages first.
- If it is extremely large, split it in two and compress each.
Settings for lighter scans next time
- Resolution: 200–300 dpi is often enough
- If you don't need color, scan in black and white (grayscale)
- For double-sided scans, use the option to skip blank pages
Note
The condition is that text stays readable after compression. Zoom in to check numbers and small text.
Use "Compress PDF" (free)Tools that go well with this
- Extract or Delete PDF Pages: Keep only the pages you need, or remove the pages you don't.
- Merge PDFs: Combine several PDF files into one, in the order you choose.
- Split PDF: Split a PDF into several files: one page each, every N pages, or by ranges.
More guides for this tool
- How to Compress a PDF to Fit a Size Limit
- What to Do When a PDF Is Too Big to Attach to an Email
- Why Text Can't Be Selected in a Compressed PDF
- Choosing Quality When Compressing: Small, Normal or High
- Typical Upload Limits on Application Forms and How to Fit Within Them
- How PDF Compression Works Without Sending Your File Out