The text looks soft. Edges fuzz out at 100% zoom. You're squinting at a document that's meant to be the final, signable, professional version.
A blurry PDF is almost always a resolution problem somewhere in its history. Where matters.
What's actually going wrong
Scanned at low DPI. A document scanned at 150dpi or below will always look soft when zoomed. Over-compressed. A previous tool downsampled images and re-encoded text as bitmaps. Wrong export setting. The source app exported at screen resolution rather than print resolution. Image-only text. The PDF looks like text but is actually a photo of text — there's no vector layer to render crisply at any zoom level.
Zoom to 400%. If the text edges are jagged and pixelated, it's an image. If they're soft but uniform, it's over-compression. If only some elements are blurry, it's mixed-quality content.
The quick fix
If you've got the source document, re-export with high-quality settings. For Word, choose 'Standard' or 'High quality' in the PDF export dialog, not 'Minimum size'.
If you only have the blurry PDF, run OCR via PDF to Word — Flint recognises the text from the image and produces a true text layer. Re-export that to PDF and you've got crisp, scalable, searchable text.
If that didn't work
Some PDFs combine sharp text with blurry images. That's fine if the layout is what matters and the images are decorative — but if the images carry data (charts, diagrams, screenshots), there's no fix beyond getting higher-resolution originals.
For old scans, rescanning at 300dpi black-and-white for text or 600dpi colour for diagrams produces dramatic improvement. If you can't rescan, convert to JPG and run the images through any decent image upscaler before converting back to PDF.
Prevent it next time
Scan at 300dpi minimum for text documents. Export from source apps at standard quality, not minimum. When compressing PDFs for size, use Flint's compressor — it's designed to keep text crisp while shrinking images.
FAQ
Does PDF compression cause blurriness?
It can if done badly. Flint compresses images while keeping text vector-sharp, so the result stays readable. Tools that downsample everything to a single resolution will blur text — avoid them.
Why is my scanned PDF blurry even at 100%?
The scan resolution was too low. 200dpi and below produces visible softness at standard reading zoom. Rescan at 300dpi for text or 400dpi for documents with small print.
Can OCR fix a blurry PDF?
OCR can recreate the text as crisp vectors even from a blurry image, as long as the original is legible to the recognition engine. The images themselves stay blurry, but the text becomes sharp and selectable.
Why does my PDF look sharp on screen but blurry when printed?
Print needs 300dpi, screens look fine at 72-150dpi. PDFs exported for screen viewing print soft. Re-export at print quality from the source application.
Sharp text starts with sharp source. Run blurry PDFs through Flint to rebuild a real text layer, then export back to PDF for crisp, scalable output.