Darken a PDF: rescue faint scans, save toner
Pale, washed-out scan? Dark slides that would eat a toner cartridge? Fix the whole document in one pass — right in your browser.
Darken faint scans and faxes
Old scanners, faded printouts and fax machines produce pale grey pages that strain your eyes and print even worse. The Darken Faint Scan preset (pre-selected above) multiplies every page's colors by 0.75: pale grey text is pushed back towards black, lines get crisper, and the paper background only dims slightly.
Because a scan is just a picture of a page, regular PDF editors can't touch it — but the multiply blend darkens the whole image evenly, text included. And since pages aren't re-scanned or rasterized, your OCR layer stays intact and searchable.
Lighten a dark PDF for printing
The opposite problem: lecture slides with black backgrounds, lecture notes written in white ink on a dark tablet, a “dark mode” document someone emailed you. Print it as-is and you'll empty a toner cartridge on page ten.
Choose the Print Lighten preset above. It remaps the tonal range — white stays white, solid black becomes a light 30% grey — so dark pages print clean and readable while photos keep a natural look. It saves dramatically more toner than a naive color inversion.
How it works
- Drop your PDF — page one previews instantly in the browser.
- Pick the preset — Darken Faint Scan for pale pages, Print Lighten for dark ones.
- Download the fixed PDF. All pages are converted with vector blend math into a new file that prints and reads the way you need.
Want the opposite direction — a comfortable dark theme for night reading? Use the PDF Dark Mode converter. Need an exact color negative? That's Invert PDF Colors.
Frequently asked questions
How do I darken text in a PDF?
Upload the PDF above and keep the Darken Faint Scan preset. It multiplies every page's colors by 0.75, pushing pale grey text back towards black. Download the result as a new PDF.
Why is my scanned PDF so light?
Old scanners, faded originals, and fax machines produce grey, washed-out pages. Because the page is an image, most PDF editors cannot fix it — but a color multiply darkens the whole image evenly, text included.
Can I make a dark PDF lighter for printing?
Yes — use the Print Lighten preset. It maps dark pages to light ones (white stays white, black becomes 30% grey) so dark slides and white-ink notes print clean without draining your toner.
Will darkening work on every page?
Yes, the preset is applied to all pages at once. Scanned pages, text pages and mixed documents are all handled.
Does it work on scans without ruining search?
Yes. Pages are recolored with vector blend modes, not rasterized, and the invisible OCR text layer is preserved — search and copy-paste keep working.