Watermark

paper · security · secret designs

Hidden by light. Watermarks are invisible unless you hold the paper up to light, where they appear as lighter and darker areas. This happens because some parts of the paper are thicker or denser than others.

Protects from fakes. Banks and governments put watermarks on money, stamps, and official documents to make them much harder to counterfeit. If someone tries to copy the document, the watermark won't copy correctly.

Made during papermaking. Watermarks aren't printed on paper after it's made, they're built in while the paper is being created. Two main methods are used: the dandy roll process and the cylinder mould process.

Shows as patterns. A watermark can be almost any design, image, or pattern. When light shines through it, you see different shades that look like a ghost picture in the paper.