This information is reprinted from the For Beginners column of Hand Papermaking Newsletter #39 (July, 1997).

The thickness of a sheet of paper, or the overall density of its fibers, primarily determines how opaque the paper will appear when held up to light. A watermark is a design made visible in the sheet of paper because the mesh of fibers is made thinner and less opaque in the image area, allowing more light to shine through.

Western-style papermakers began using thin, bent wire to form watermarks in the thirteenth century. They continue to do so today. Most often the trademark of a particular mill, these linear designs are made by attaching the wire to the surface of the mould. While the concept is simple, this method is often time consuming and may require a skillful hand, depending on the intricacy of the design. During sheet formation, the layer of pulp deposited on the mould is thinner where the wire design lies, and is thus less opaque in the final sheet. The image is impressed farther into the sheet during couching.

By the mid-nineteenth century, papermakers were no longer limited to the linear watermark designs created with traditional bent wire. A new technique for creating shadowmarks or chiaroscuro (light and shade) watermarks allowed papermakers and the artists who worked with them to create more subtle images with varying opacity. Gradations of tone are realized because of small differences in the density or thickness of the paper pulp from one image area to another. As with watermarks made using wire, these images are seen best when backlit. This type of watermark was commonly used for currency, since the effect is hard to reproduce.

Chiaroscuro watermarks start with a sculpted design. A relief sculpture, generally made of wax, is the model for a die and matrix. These give shape to a fine wire mesh that is attached to the screen of a papermaking mould. This shaped area of the screen collects varying amounts of pulp as the fiber settles when a sheet is pulled. (See the Summer 1994 issue of Hand Papermaking for a description and photos of the famous chiaroscuro watermarks created at the Magnani mill in Italy.)

While bibliographers use watermarks to trace the history of paper (see the article by Brett Charbeneau in Hand Papermaking's Winter 1993 issue), papermakers enjoy the beauty and distinction a watermark adds to their sheet. Modern papermakers continue to employ the traditional methods outlined above while experimenting with newer techniques, such as photo-etched magnesium watermarks. The Summer 1996 issue of Hand Papermaking features an article and sample from Katie Macgregor and Bernie Vinzani, who use computer-generated images and sign-making equipment to create intricate watermarks. Whatever the technique, traditional or modern, the goal is the same: to create an attractive design within the sheet using subtle variations in paper thickness.

by Tom Bannister