PDF Watermark
Text watermarks are rendered to a transparent image before being placed in the PDF, which is why Chinese and Japanese work. The trade-off is that the watermark is not selectable or searchable.
Drop PDFs here, or click to pick
Drop a PDF or click to pick one — the watermark is applied locally
Watermark added
DownloadAbout PDF Watermark
Stamp text or image watermarks onto a whole PDF or selected pages, with control over position, angle, opacity and tiling. Compositing happens locally; the file is never uploaded.
How Chinese text works
pdf-lib's built-in fonts cannot encode Chinese, and embedding a CJK font means megabytes. So the text watermark is drawn on a canvas with the browser's own fonts and placed into the PDF as a transparent image — Chinese, Japanese and emoji all work.
The trade-off is real: the watermark is an image, so it cannot be selected or searched inside the PDF. Fine for a copyright mark; searchable watermark text would need embedded fonts, which is a different class of tool.
When to tile
A single watermark is easy to crop away or retouch. A page covered in them makes any removal destroy the layout. Keep opacity around 15–25% so it is obvious without hurting readability.
Sharpness and size
Text is rendered at 4x before being placed, so edges stay clean in print. The size cost is small: the watermark image is stored once and referenced by every page.
Frequently asked questions
Does the watermark bloat the file?
Barely. The image is stored once and referenced by every page — typically tens to a couple of hundred kilobytes.
Can I apply it to only some pages?
Yes. Put 1,3,5 or 2-8 in the page range; leave it blank for all pages.
Can the watermark be removed later?
If you added it here, yes — regenerate from the original file. If the original is gone, the watermark is baked into the page and only a retouching tool could remove it, badly.
