Watermark
Also known as: image watermark, PDF watermark, overlay text on image, logo overlay
A watermark is text, a logo, or a pattern overlaid on an image or document to mark ownership, signal status (such as "Draft" or "Confidential"), or discourage unauthorized reuse. It can be visible and semi-transparent, or invisible and embedded in the file.
- Can be visible (overlay) or invisible (embedded)
- Used to mark ownership, status, or origin
- A deterrent, not a substitute for encryption
Visible vs invisible watermarks
A visible watermark is a graphic or text layer placed over the content — a logo in a corner, a tiled "Sample" across a photo, or a diagonal "Confidential" stamp on a PDF. It is usually semi-transparent so the underlying content stays readable.
An invisible watermark is encoded into the pixels or file data and is not seen by eye. It is used to trace leaks or prove provenance, and special software is needed to detect it.
Common uses
Photographers and stock sites watermark preview images to protect originals. Businesses stamp PDFs with status labels like Draft, Approved, or Confidential before sharing them.
A visible watermark is a deterrent, not encryption — it can often be cropped or edited out. For real access control, protect the document with a password or encryption instead.