Colour PDF to greyscale: remove colour for cheaper printing

1 min read·25 July 2026

Converting a colour PDF to black and white reduces printing costs and makes the document suitable for black-and-white printers and copiers. PDFrust does it free in your browser.

Why convert to greyscale?

Black-and-white printing is cheaper than colour (up to 5–10x cheaper per page). Some printers only support black and white. Greyscale PDFs are smaller in file size. Legal and official documents sometimes require black-and-white formatting.

Difference between greyscale and black and white

Greyscale preserves all gradations of light and dark — photos remain recognisable, text stays readable. Black and white (binarisation) makes everything purely black or purely white — better for text and line drawings, worse for photos. PDFrust uses greyscale for the best results.

PDF grayscale

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Images in the document

Colour images are converted to grey versions. Details are preserved but colour information is lost. If you want to keep the original colour images separately, save them as JPG before converting.

Effect on file size

Greyscale PDFs are typically smaller than colour PDFs because colour data is reduced. Combine with the compress tool for maximum reduction.

Partial use

Want only certain pages in greyscale? Use the split tool to extract the desired pages, convert to greyscale, and merge with the rest using the merge tool.