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Grayscale PDF
Grayscale PDF converts colour pages to true monochrome by rendering every page and applying the Rec. 709 luminance formula pixel by pixel, then rebuilding the document from those grey images. Colour logos, highlight layers and RGB text styles all become shades of grey.
How to use Grayscale PDF
- Upload the colour PDF you need in black and white.
- Start the conversion; each page is rendered, converted and re-embedded.
- Download the grayscale document.
Where Grayscale PDF is useful
- Cutting colour printing costs on internal handouts.
- Producing a print-friendly version of a colour-heavy brochure.
- Preparing a document for scanning or archival workflows that expect monochrome.
Formats, algorithms and limits
Grayscale is computed with the standard luminance weights 0.2126 red, 0.7152 green and 0.0722 blue, which matches how print shops convert colour. Pages are rewritten as images, so the output has no selectable text layer and may shrink in size on photo-heavy documents.
Troubleshooting and honest limits
- Test a single page first if the document relies on colour coding to carry meaning — grey values can merge.
- Keep the colour original for archiving; this conversion cannot be undone in the output file.
- Because pages are re-rendered, very small text should be checked after conversion.
Frequently asked questions
Will the grayscale result really be black and white?
It is true greyscale: every pixel carries a luminance value with equal red, green and blue channels. For pure 1-bit black and white you would additionally need a threshold step in a print workflow.
Does greyscale affect the file size?
Usually it shrinks: three colour channels are replaced by one grey value and pages are JPEG-encoded. Documents made only of text may change little.
Can I still select text after conversion?
No. Pages are flattened to images, so text becomes part of the picture. Use the original file if you need copyable text.
Does it work on scanned documents?
Yes, and it is often used to remove colour casts from photographs of paper.
Related tools
Page written and reviewed by the FreeConvertio engineering team on 2026-10-14. Grayscale PDF runs entirely in your browser — no uploads, no account and no daily limits.