How to watermark a PDF
Stamp DRAFT, CONFIDENTIAL or your name across a PDF before sharing it. How to make it visible without ruining the page and how hard it is to remove.
A watermark answers a question before anyone asks it: is this the final version, can I share it, who does it belong to. DRAFT stops a work in progress being mistaken for the real thing, CONFIDENTIAL reminds everyone who handles it how to treat it and a name across the page makes it clear where a leaked copy came from.
Adding one
Watermark PDF stamps text across every page or only the first. Choose the words, the size, the angle, the colour and the opacity and a preview shows the first pages before you download. The original content stays exactly as it was underneath, including searchable text.
Making it visible without spoiling the page
- Opacity around 15 to 25 percent is unmistakable yet leaves the text readable.
- A diagonal angle crosses the page without lining up with lines of text.
- Size large enough to be seen at a glance; a small watermark is easy to overlook.
- Repeat across the page for documents shared outside your organisation, such as proposals and price lists. It is much harder to crop out of a screenshot.
How permanent is it?
A watermark added as text sits on top of the page. Someone with a PDF editor can remove it, so it is a deterrent and a label rather than a lock. For a copy that can’t easily be cleaned, convert the watermarked pages to images and rebuild the PDF from them; the stamp then becomes part of the page. The same flatten-and-rebuild approach is how proper redaction works.
Photos
For photos rather than documents, the image watermark tool adds your name or site to a whole folder at once, in a corner or tiled.
Signing and sending
A document marked CONFIDENTIAL is often also one that needs signing. The steps for that are in how to sign a PDF without printing it. Watermark first, then sign, so the signature sits on top.
Common questions
What opacity should a watermark be?
Around 15 to 25 percent for a single diagonal stamp: unmistakable, but the text underneath stays easy to read. Repeated watermarks should be lighter, since there are more of them.
Can someone remove my watermark?
A watermark added as text on top of the page can be removed by someone with a PDF editor and the determination to do it. To make it much harder, convert the watermarked pages to images and rebuild the PDF, which merges the stamp into the page itself.
Can I watermark photos too?
Yes, with the image watermark tool, which adds text to a batch of photos, in a corner or tiled across the picture.
Will a watermark make the text unsearchable?
No. The watermark is added on top and the original text stays selectable and searchable underneath.