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Add a watermark to a PDF

Stamp text across every page. Control the size, angle, colour, and opacity.

Watermark PDF

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How to watermark pdf

  1. Drop the PDF. Page one previews so you can see the watermark before committing.
  2. Set the stamp. Type the text, then adjust angle, size, opacity, colour, and position.
  3. Apply and download. The watermark is drawn onto every page and the file saves to your device.

About watermark pdf

A watermark is a claim about status. DRAFT means do not act on this. CONFIDENTIAL means do not forward it. A name and date across a scanned ID means this copy was issued for one purpose and should not be reused for another. In every case the point is that the mark travels with the document, which means it has to be drawn into the pages rather than added as a viewer annotation.

The tool draws the text directly onto each page's content stream with pdf-lib, using a standard embedded font. Because it is part of the page rather than an annotation layer, it survives printing, flattening, and re-saving in other software. It cannot be toggled off in a viewer, and removing it cleanly requires deliberate effort rather than a right-click. That is the intended behaviour — a watermark that can be dismissed is decoration.

Angle, opacity, and size are the three controls that matter. A diagonal stamp at around 45 degrees and low opacity sits behind the text and stays readable without obscuring the content, which is the conventional look and the right default for most documents. A horizontal stamp at higher opacity reads as a status label. Very low opacity looks elegant and photographs badly, which is worth knowing if the document might be screenshotted or printed and scanned.

Being honest about the limits: a text watermark is a deterrent and a label, not a security control. It does not encrypt the document, does not prevent copying, and can be removed by someone determined enough. If you need the content itself restricted rather than marked, a watermark is the wrong tool and no browser-side stamp will fix that. What it does well is make the status of a copy unambiguous to anyone looking at it.

Common settings

PurposeTextAngleOpacity
Draft documentDRAFT45°15%
Restricted circulationCONFIDENTIAL45°20%
Issued copy of an IDFor [purpose] only — [date]35%
Sample or previewSAMPLE45°25%
Superseded fileSUPERSEDED30%

Watermark PDF FAQ

Can the watermark be removed?

Not easily, and not by toggling something in a viewer. The text is drawn into each page's content, not added as an annotation. Someone determined can still remove it — a watermark is a label, not a lock.

Will the watermark print?

Yes. Because it is part of the page content rather than a viewer annotation, it prints exactly as it appears on screen.

Can I watermark only some pages?

The current tool stamps every page. To mark a subset, split those pages out, watermark them, and merge the document back together.

What opacity should I use?

Around 15 to 20 percent for a diagonal background stamp that stays readable behind text. Push to 30 or 35 percent for a horizontal status label that needs to be noticed immediately.

Does watermarking make the file bigger?

Barely. Text and a standard font add a small amount per page. The change is usually well under a percent of the original size.

Is this the same as password protecting a PDF?

No. A watermark labels a document. It does not encrypt it or restrict what can be done with it. They solve different problems.

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