Strip every colour out of your PDF and produce a clean, neutral greyscale document — ideal for cheap monochrome printing, ink savings, professional document submissions and B/W e-readers. All in your browser, no upload.
Click to select a file or drag and drop
A single PDF file
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Drop a single PDF onto the upload zone or pick it from your device. The file is processed locally in your browser — nothing is uploaded.
ZentoPDF rewrites every colour space (RGB, CMYK, spot colours) into a luminance-weighted grey value so text stays sharp and photos keep their natural shading.
Click download to get a brand-new greyscale PDF, ready for monochrome printing, archiving or sharing on B/W e-readers. The original colour file is left untouched.
Fine-tune brightness, contrast, saturation and more in your PDF.
Create a "dark mode" version of your PDF.
Reduce the file size of your PDF documents while maintaining the best possible quality.
Convert PDF to image-based PDF. Flatten layers and remove selectable text.
Make your PDF look like a scanned document.
Monochrome printing is dramatically cheaper than colour printing — many offices and copy-shops charge 5–10× less per greyscale page. Pre-converting your PDF also guarantees a consistent look (no surprise tints) and is often required when submitting documents to courts, universities or government agencies.
Yes. ZentoPDF keeps text as native vector PDF content and simply changes the colour of each glyph to its luminance-equivalent grey, so text remains crisp and selectable at every zoom level — no rasterisation, no fuzziness.
Images are re-encoded using the standard ITU-R BT.601 luminance formula (0.299 R + 0.587 G + 0.114 B), which is the same formula TV and photo software use to create natural-looking black-and-white photos that preserve contrast and detail.
Yes — the whole process runs in your browser with pdf-lib. Your original colour PDF and the new greyscale version never leave your device, which makes the tool safe for sensitive contracts, medical records or internal documents.
The output is a new greyscale PDF; the original colours cannot be reconstructed from it. Always keep a backup of the source file if you might need the colour version later — ZentoPDF never overwrites your original file.