Optimize PDF

Turn a PDF black and white, text still sharp

This tool turns every colour in a PDF grey, in your browser, for printing in black and white or meeting a submission rule. Unlike tools that turn each page into a photo, it changes the colours themselves: text stays sharp, selectable and searchable, and the file stays about the same size.

or drop files here, or paste with Ctrl/Cmd+V

PDF · up to 50 files · 100 MB each

No file to hand?

Your files stay on your device. Nothing is uploaded. Check it yourself

How to use Greyscale PDF

  1. Add your PDFs

    Drop one or more PDFs on the box, or click to browse. Up to 50 files of 100 MB each.

  2. Check the preview

    You see your first page, and roughly how it will look in grey.

  3. Convert and download

    Press Make greyscale, then download the PDF, or all of them as a zip.

How the colours become grey

Colour in a PDF comes from two places. Drawing instructions such as "fill with red" are rewritten to the grey with the same lightness, using the standard weighting of red, green and blue that printers and screens use.

Named colour spaces, which photos, gradients and many drawings use, are replaced with a grey version that has the same number of colour values. Every PDF reader then shows them in grey, so a photo goes grey without being decoded and saved again.

Forms, patterns and annotation drawings inside the file are followed and converted too. Nothing else changes: fonts, links, bookmarks and form fields stay as they were.

Questions about Greyscale PDF

How do I convert a PDF to black and white?

Add the PDF above and press Make greyscale. Text, shapes, photos and gradients turn grey with the same lightness they had, so dark colours stay dark and light colours stay light.

Will the text still be searchable?

Yes. Pages are not turned into pictures. Only the colours are changed, so text stays real text that you can select, copy and search, and it prints as sharp as before.

Does the file get bigger?

Hardly. Photos are not re-encoded: each image keeps its data and is told to show in grey. The file grows by a few kilobytes at most, and often stays the same size.

Is anything left in colour?

Rarely. Spot colours that use complex ink definitions, a few JPEG 2000 images, and small images stored inside the page drawing itself can keep their colour. Look through the result before printing a large job.

Will it save colour ink when printing?

Usually. A greyscale file asks the printer for no colour at all, so most printers print it with black ink alone. Some inkjets still mix in colour to make smooth greys; choosing greyscale in the print dialog as well settles it.

Is it safe to convert a PDF to greyscale online?

With PlumPDF the PDF never leaves your device. It is changed in your browser tab.

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