How to use Grayscale PDF
- Choose the PDF.
- Pick standard or high quality.
- Select Convert to grayscale and download the result.
Black-and-white pages for printing
Colour pages can be expensive to print, and some printers use colour ink even for documents that only need black. Converting a PDF to grayscale gives you a file that prints in black and white on any printer and looks the same on screen as it will on paper, so there are no surprises when faint colours turn out too light.
Each colour becomes a shade of grey that matches how bright it looks to the eye. Yellow becomes a light grey and dark blue a dark grey, following the Rec. 709 brightness formula used for video, rather than a plain average that makes some colours look wrong.
How it works
Every page is drawn by pdf.js in your browser at the quality you choose, converted to grey, and placed back into a new PDF at its original page size. Standard quality, 150 dots per inch, is right for most printing and keeps files small; high quality, 300 dots per inch, suits small print and detailed graphics but makes a larger file.
What to expect
Because each page is redrawn as a picture, text in the grayscale copy can no longer be selected, searched or copied, and links stop working. Keep your original if you need those. If you need searchable text afterwards, OCR PDF can add a text layer to the grayscale copy. To shrink a large result, run it through Compress PDF.
Private by design
The conversion happens in your browser, using pdf-lib and pdf.js, open-source libraries that run on your device. Your PDF is never uploaded, so contracts, statements and personal documents stay on your computer. Nothing is stored after you close the tab, and there is no account, watermark or file limit.
It works offline once the page has loaded, in any modern browser on Windows, Mac, Linux, Android and iPhone. Because nothing is sent to a server, results appear as fast as your device can produce them, even for long documents.
Questions
- Is my PDF uploaded?
- No. The PDF is processed in your browser and never leaves your device.
- Can I still select the text?
- No. Each page is redrawn as a grayscale picture, so text becomes part of the image. Keep the original if you need to copy text from it.
- Why not just print in black and white?
- Printers convert colour in different ways and some still use colour ink. A grayscale file looks the same on every printer and on screen.