Convert PDF to Grayscale

1. 1Add the colour PDF.
2. 2Choose a resolution — Standard suits most printing, Print is for anything with fine detail.
3. 3Press Convert to grayscale and wait while the pages are processed.
4. 4Download the black-and-white version; the original is untouched.

Each page is rendered by the same engine a browser uses to display PDFs, then every pixel is converted using the Rec. 709 luminance weighting — about 21% red, 72% green and 7% blue. That weighting matches how the eye judges brightness, so a red heading and a blue heading of similar visual weight end up a similar grey, instead of the muddy result a plain average gives.

The converted pages are written back at their original size in points, so the paper size, margins and proportions of the document do not change. Only the content within each page becomes a picture.

That is the trade-off worth knowing: because the page is re-rendered, the text in the result is no longer selectable or searchable. It prints identically, but keep the original if you need to copy text out of it later.

The file is read into your browser's memory, changed there, and handed straight back to you. Nothing is uploaded, so there is no queue and no copy sitting on a server afterwards.

• Use Standard for ordinary documents and Print for small type, fine lines or anything going to a print shop.
• Check charts and coloured highlights in the result. Two colours with the same brightness become the same grey.
• Keep the colour original; the grey version cannot be turned back into colour.
• If you only need a mono printout once, the black-and-white option in your print dialog is quicker.

• How to print several PDF pages on one sheet of paper
• How to print a PDF in black and white — and save ink
• How to turn a photo black and white — the three methods compared
• How to read a PDF in dark mode