How to convert a PDF to black and white

1 min read·25 July 2026

Converting a PDF to black and white makes it smaller and more print-friendly on monochrome printers. With PDFrust you convert the pages to greyscale directly in the browser — no installation, nothing uploaded to a server.

When do you need this?

You want to print a colour document on a black-and-white printer. Or you want to reduce the file size by removing colour information. Or you need a business document that looks more formal in greyscale.

How does black-and-white work in PDFrust?

The compress tool in PDFrust renders each page as an image and saves it in greyscale. Upload your PDF, choose the greyscale option, and download the result. Text and images are both converted.

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What changes?

All colour pages are converted to greyscale. Text that was originally black stays black. Coloured charts, logos, and photos turn grey. The PDF structure stays intact.

Smaller file after converting?

Yes, greyscale images are smaller than colour images. Especially with PDFs containing many photos or charts you will notice a clear reduction in file size alongside the colour conversion.