PDF Watermark
PDFAdd text watermarks to PDFs with custom font, size, color, opacity, rotation and position. Tile across all pages or place it in a corner, all browser-based.
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About PDF Watermark
This PDF watermark tool adds text watermarks to PDF documents locally in your browser using pdf-lib, so files never leave your device. It draws watermark text onto each page via drawText with control over font size, color (RGB), opacity (0 to 1), rotation and coordinates. Three layout modes are available: centered, tiled across the full page, and custom coordinates, plus a page-range selector so you can watermark only certain pages (e.g. 1-3,5). Typical labels include "Confidential", "Draft", "Sample" and "Internal Use". It is worth setting expectations: a text watermark is a semi-transparent overlay that deters unauthorized copying and aids traceability, but a determined editor can theoretically remove it, so treat it as protection-in-depth rather than encryption. Due to pdf-lib's built-in font limits, Latin and English text works out of the box while Chinese generally needs an embedded CJK font — English or pinyin labels are recommended. Watermarking never touches your original content and adds only a few KB to the file.
How to Use
- Open the PDF Watermark tool
- Upload the PDF file
- Adjust the output options as needed
- Click the Process button; results appear in real time
- Copy or export the result
Use Cases
- Confidential Marking — Add a "Confidential" watermark to internal contracts and financial statements to signal sensitivity and reduce leakage risk.
- Draft Status — Stamp unfinished reports or proposals with "Draft" so incomplete versions are not mistaken for final.
- Sample Protection — Watermark externally shared samples or demos with "Sample" to discourage unauthorised copying.
- Copyright Notice — Add copyright information to courseware, e-books and white papers to assert ownership.
- Exam Anti-Cheating — Watermark electronic exam papers with candidate names or IDs to trace the source of any leak.
FAQ
Can the watermark be removed?
The text watermark overlays page content and cannot be removed by simple text copy. However, professional PDF editors can theoretically delete it - watermarks serve mainly as a deterrent and traceability aid.
Are Chinese watermarks supported?
Due to pdf-lib's built-in font limitations, English and basic Latin characters are supported by default. Chinese watermarks require an embedded CJK font file - English or pinyin labels are recommended.
Can I watermark only some pages?
Yes. Specify pages by range (e.g. `1-3,5`); only those pages get the watermark while the rest stay clean.
Can position and angle be customised?
Yes. Choose preset positions like centred or tiled, or set a custom rotation angle (e.g. 45° diagonal) and opacity to suit your needs.
Will the file get larger?
A text watermark is tiny - typically a few KB - so the impact on overall file size is negligible.
Will the watermark hide the body text?
By default the watermark is semi-transparent and faint enough to read through; you can also adjust placement and tile density to avoid covering key content.