A smaller PDF is only useful if it stays readable. See where the size comes from, then compress in steps you can check.
| Metric | Before | After |
|---|---|---|
| File | report-scan.pdf | report-scan.pdf |
| Size | 12.4 MB | 4.5 MB |
| Reading | full quality | still legible |
Everyone wants a smaller PDF, but a file that's tiny and unreadable isn't a win. The trick is to compress only as much as the file actually needs, and to check what you get.
Where the size comes from
Scanned PDFs are large because they're collections of images. File size tracks how big and detailed those images are. Reduce image quality or resolution and the file shrinks — that's the whole lever.
Not every page needs the same treatment
A text-heavy document survives moderate compression easily because there isn't much pixel detail to lose. A scanned page with a photo, diagram, or signature needs more care — push too far and fine lines blur.
Compress in controlled steps
Rather than crushing to the smallest possible size in one attempt, compress to a level you can still read, then check a page with fine detail. Adjust only if the file is still too large.
A realistic example: a scanned report at 12.4 MB compressed on the medium setting comes out around 4.5 MB — under most submission limits while keeping the text legible.
When to accept the trade-off
If the document's only job is a quick skim or an upload with a hard size limit, some quality loss is fine. If you'll read it closely or need to preserve it, keep quality higher and accept the larger file.