How to reduce the size of a scanned PDF
Reduce the file size of scans by choosing suitable quality, keeping the original and checking that the result is legible.
First check what you want to keep
okPDF compression is designed for scans: it recreates each page as a JPEG image. Selectable text, links and vector graphics are not preserved. For a digital document where these elements are important, consider extracting only the necessary pages first.
Choose quality
“Balanced” uses 144 DPI to balance readability and file size. “Smaller file” uses approximately 96 DPI: it can be useful for a preview, but small text and details may become less clear.
A short document that is already optimized may not become smaller. If the new file is not smaller than the original, the download contains the unchanged original; the result message tells you this.
A practical example
You have a ten-page scan to send. Keep the original, try balanced quality and reopen the downloaded PDF. Zoom in on a page with small text and check stamps and numbers. If the file is still too large, try the other quality setting and compare the results. A specific final file size, such as “under 1 MB”, is not guaranteed.
If you also need searchable text
You can apply OCR to the compressed copy, keeping in mind that the new text layer may increase the file size. If the scan is hard to read, use the original for recognition: aggressive compression can reduce accuracy.