Editing Watermark (section)

=== Dandy roll process ===
[[File:Dandy Roll.png|thumb|right|A perspective view of a dandy roll in accordance with the invention of a conventional paper-making machine incorporating watermarks into the paper]]
Traditionally, a watermark was made by impressing a water-coated metal stamp onto the [[paper]] during manufacturing. The invention of the dandy roll in 1826 by John Marshall revolutionised the watermark process and made it easier for producers to watermark their paper.

The ''dandy roll'' is a light roller covered by material similar to [[window screen]] that is embossed with a pattern. Faint lines are made by ''laid wires'' that run parallel to the axis of the dandy roll, and the bold lines are made by ''chain wires'' that run around the circumference to secure the laid wires to the roll from the outside. Because the chain wires are located on the outside of the laid wires, they have a greater influence on the impression in the pulp, hence their bolder appearance than the laid wire lines.

This embossing is transferred to the [[Wood pulp|pulp]] [[fibre]]s, compressing and reducing their thickness in that area. Because the patterned portion of the [[page (paper)|page]] is thinner, it transmits more [[light]] through and therefore has a lighter appearance than the surrounding paper. If these lines are distinct and parallel, and/or there is a watermark, then the paper is termed ''laid paper''. If the lines appear as a [[mesh]] or are indiscernible, and/or there is no watermark, then it is called ''wove paper''. This method is called ''line drawing watermarks.''