Document watermark tool
When handing out document copies, you often need a watermark like COPY, CONFIDENTIAL, VOID or SAMPLE so a copy isn't mistaken for the original or leaked. This tool lets you upload an image (e.g. a scanned document) and overlay a tiled, diagonal watermark, adjusting the text, opacity, font size and angle, then download a PNG.
Common uses
- Mark an ID/document copy with "COPY" to prevent misuse.
- Mark a contract draft "SAMPLE / DRAFT" to distinguish it from the original.
- Mark a cancelled voucher "VOID".
- Mark internal documents "CONFIDENTIAL".
Privacy
The image only loads into your browser and the watermark is drawn and exported on a canvas — nothing is uploaded — making it safe for sensitive or confidential documents.
FAQ
Which image formats are supported?
Common formats such as PNG and JPG. To watermark a scanned document, export the PDF to an image first, then upload it; the output is a PNG.
Is my image uploaded?
No. The image only loads into your browser and the watermark is drawn live on a canvas — nothing is sent to a server, so it is suitable for confidential documents.
Can I customise the watermark text?
Yes. Besides presets like COPY, CONFIDENTIAL, VOID and SAMPLE, you can enter any Chinese or English text and adjust opacity, font size and angle.