Convert a PDF to grayscale
FileReshape's Grayscale PDF tool turns every colour in a PDF into a shade of grey: text, lines, shapes and pictures. It runs in your browser with pdf-lib and pdf.js, and the file is not uploaded. Text stays real, sharp text; a page with colour gradients or spot colours is turned into a grey picture instead, and a PDF with many photos can get larger.
Did a file not convert correctly? E-mail [email protected], ideally with a small sample file, and it will be fixed.
Key facts
- Works with: PDF (.pdf).
- Your files are not uploaded: the work is done in your browser, on your own device.
- File size: no fixed limit; very large files are limited by your device's memory.
- Needs a current browser (Chrome, Edge, Firefox or Safari) on a computer, tablet or phone; nothing to install.
- Free to use, with no sign-up.
Why convert a PDF to grayscale
Printing a colour PDF on an office printer uses colour toner even for a blue heading, some print shops charge colour prices for any page with a trace of colour, and theses, court filings and job applications sometimes have to be handed in as black and white. A grayscale copy shows exactly what the printed page will look like and keeps the coloured ink out of it. This tool rewrites the colours inside the PDF: each red, blue or CMYK colour of text, lines and filled shapes becomes the grey with the same brightness, and colour pictures are converted pixel by pixel. Text stays text, so it can still be selected and searched, and lines stay sharp at any zoom. A few things cannot be changed this way, such as colour gradients, patterns, spot colours and some picture formats; a page that uses them is drawn as a grey picture at the resolution you choose, and the result says how many pages that affected. You can also choose to turn every page into a grey picture, which always works but makes text unsearchable. Everything runs in this page, so the document stays on your device.
How to make a PDF black and white
- Drop your PDF in the box, or click to choose it.
- Keep the first method to keep text sharp, or choose to turn every page into a grey picture, and pick the resolution.
- Click Convert to grayscale and download the grey copy; your original file is not changed.
What changes when you convert
Brightness, not colour, is kept
Each colour becomes the grey of the same brightness, the way a black-and-white photo does it. Colours that differ but are equally bright, such as a red and a green line in a chart, can end up as almost the same grey. Check charts and maps in particular, and add labels if the colours carried the meaning.
Pages that become pictures
Gradients, patterns, spot colours and pictures in unusual formats such as JPEG 2000 cannot be rewritten safely, so such a page is drawn as a grey picture instead. The text on that page can then no longer be selected or searched, and links on it stop working. Choose 300 DPI if those pages will be printed.
The file size can change
Colour photos are stored as lossless grey pictures, because a browser cannot write a grey JPEG, so a PDF full of photos can get bigger, while a text document usually gets a little smaller. Run Compress PDF afterwards if the size matters.
Signatures and forms
Changing the colours rewrites the pages, so a digital signature in the file is no longer valid. Form fields keep working, but the colour of their borders and backgrounds is drawn by your PDF reader and may stay in colour.
About the formats
PDF (Portable Document Format) was created by Adobe in 1993 and has been an ISO standard since 2008. A PDF looks the same on every device, which is why it is used for contracts, invoices, forms, manuals and scanned documents.
- A page can hold text, vector graphics and images, each placed exactly.
- Scanned documents are usually one image per page.
- A PDF can be protected with a password that is needed to open or edit it.
Frequently asked questions
Is my PDF uploaded?
No. The colours are changed by pdf-lib and pdf.js inside this web page on your device, and nothing is sent to a server.
Is grayscale the same as black and white?
Grayscale keeps all the shades between black and white, so photos and light backgrounds still look natural. Pure black and white with no greys at all is rarely what you want for a document, and it is not offered here.
Can I turn the grey PDF back into colour?
No, the colour information is gone in the copy. Keep your original file; the tool never changes it.
Will my printer really print it without colour?
The pages contain only grey, so a colour printer has no colour to print, although some printers still mix black from colour toner. Choosing Grayscale or Black and white in the print dialog as well makes sure.