How to Add Watermark to PDF Free Online
A visible watermark is not a security control. Use a label such as DRAFT or REVIEW COPY to communicate status, not to prevent copying, editing or removal. PDFcraft adds text across every page rather than encrypting the document.
Controls versus fixed behavior
| You choose | The tool determines |
|---|---|
| Text | Helvetica Bold font and gray color; unsupported characters can cause an encoding error. |
| Opacity: 10%-80%, in 5% steps | Default 30%; no independent color or image-logo setting. |
| The input PDF | One label on each page at a displayed 45-degree angle, fitted to its visible area. |
Label a review copy
Start with a short status label
DRAFT is easier to inspect than a long paragraph. The default is CONFIDENTIAL, but the wording itself creates no access restriction.
Choose opacity for the underlying content
A dense diagram needs a different readability check from a mostly blank page. There is no preview-based placement control; inspect the saved result.
Check varied pages
Review a portrait page, a landscape page and any unusually cropped page. Keep the original if the label obscures content or becomes too small.
Why long text shrinks
Placement uses the crop/media intersection and existing rotation. Font size begins from the visible page dimensions and is reduced to fit the diagonal text box. There is no fixed character-count limit, but that does not imply every character or arbitrarily long text will be usable. Very long labels can become tiny; invalid page geometry can stop processing.
What is added - and what is not removed
The label is drawn into page content. Existing text is not redacted, and there is no image-logo import, tiled pattern, manual angle or font picker. Geometry and extraction tests observed placement and added text on controlled inputs, not universal visual fidelity. An editor may be able to remove the overlay.
Keep the labeling workflow separate from access control
For an opening password, use Protect after labeling and verification. Neither a watermark nor a successful save proves signature preservation. Watermarking runs locally; loading the website still requires web resources.
Tools for this task
Frequently asked questions
Why does the same label have different sizes on different pages?
The fitting calculation depends on each visible page area and the length of the text. It is not a fixed font-size setting shared by every page.
Can I use the label to hide a confidential paragraph?
No. Drawing over a paragraph is not secure redaction. The underlying content is not purged by adding a watermark.