If you are distributing board documents, financial projections, or term sheets, you need a way to discourage sharing and identify a copy’s origin. A visual watermark is a standard approach. However, it is important to understand what a watermark is technically and the correct order of operations when preparing files for distribution.

The tool runs in your browser, so the file is not uploaded.

What the watermark is technically

When you use the Watermark PDF tool, the watermark you apply is live text added to each page. It is not flattened into the background image, and it is not an annotation.

Because it is ordinary text, it shows up in copy/paste operations and document search. Most importantly, it is removable. Anyone with a capable PDF editor can select the watermark text and delete it (cpdf manual). Therefore, a watermark should be treated as a deterrent against casual sharing rather than an impenetrable security measure. A uniform CONFIDENTIAL stamp does not trace leaks — tracing requires generating one copy per recipient with their specific identifier.

Configure the Watermark

For board documents, the watermark should be prominent but not obscure the text. In the tool, you can configure:

  • Text: Enter the recipient’s name or email address (Latin characters only).
  • Opacity: Adjustable from 10% to 100% (15% to 25% is suggested).
  • Size: Adjustable from 18 to 96 (default is 48). The font is fixed to Helvetica Bold and the colour is fixed to light grey.
  • Position: Choose Center (which applies a fixed 45-degree diagonal placement) or one of the four corners (horizontal placement).

Order of operations

Do these steps in order. The watermark tool cannot open an encrypted PDF (pdf-lib does not support encrypted documents), so you must apply the watermark before adding a password. Note that watermarking keeps the existing Title and Author metadata while setting the Producer to pdf-lib.

Follow these steps for each recipient:

  1. Watermark: Run Watermark PDF to stamp the document with the recipient’s identifier.
  2. Remove Metadata: Use PDF Metadata Remover to clear the document properties (Info dictionary). It does not remove XMP metadata; you can read more about why clearing PDF properties can leave XMP metadata behind.
  3. Encrypt: Finally, use Protect PDF to add an AES-256 open password (qpdf encryption docs). For further details on secure distribution, see how to protect a PDF before sharing.