Clean up a scanned PDF (contrast, B&W)
Improve the readability of a scanned PDF (grayish background, faint text) before printing by increasing the contrast, or convert it to pure black and white for a crisp, ink-saving result.
How it works: each page is rendered as an image, cleaned, then reassembled into a PDF. The resulting document therefore no longer has a selectable text layer (like any scan); use this tool on PDFs that are already scanned, not on native text documents.
How it works
A document scanned with a flatbed scanner or a mobile app often has a slightly gray or yellowed background and text that isn't quite black, which wastes ink when printing and hurts the legibility of photocopies. The tool renders each page as a high-resolution image in your browser (via pdf.js), applies the treatment you chose (contrast enhancement or black-and-white thresholding), then reassembles all the cleaned pages into a new PDF.
Which mode should I choose: contrast or pure black and white?
Contrast enhancement keeps shades of gray and works well for scans with photos or diagrams. Pure black-and-white mode (threshold) turns every pixel fully white or fully black: ideal for a text-only document, it gives the sharpest print and the smallest file, but removes all shades of gray and color.
Does the text become selectable again after cleaning?
No. The result remains an image of each page, like any scan: cleaning improves the visual appearance and the printout, but does not restore selectable or searchable text. For that, you would need a separate OCR step after cleaning.
100% local processing: rendering relies on pdf.js and cleaning on our WebAssembly module, both running entirely in your browser — your scan is never sent to a server.