Put it on Paper

Look at an old map, from around 1800 or older, and notice the paper it’s printed on. It’s think and hefty, not thin and flimsy like the paper modern road maps are printed on. The paper has a slightly toothy texture rather than perfectly smooth. Hold it to the light and look for crisscrossing lines and watermarks. These are the signature traits of old paper.

Paper is made of cellulose, plant fiber, in a slurry, that’s dried in thin sheets. Before the mid 1800s, the source of the cellulose was linen and cotton, pulverized with water to make pulp. The pulp was spread on wire mesh, pressed and dried. Later on, wood pulp paper became the norm.

Cellulose is a material made by plants for use in their structures, consisting of individual glucose molecules bound together with special chemical bonds making them very strong. Short by our scale, far too small to be seen by the eye, but large on the molecular scale, these strings weave together in the pulp to form a mat. Rag and wood pulp papers differ in that the cellulose strings in rag pulp are between three and ten times the length of those in wood pulp paper; rag papers’ fibers are far more interlaced than those of wood pulp papers, making a stronger and more flexible sheet. But that’s not the only difference: the cellulose in wood comes packaged with other materials, occluding lignins and sulfur based compounds, contributing to the faster breakdown of the paper.

The wire mesh used in laid paper manufacture left a telltale crisscross pattern. Termed chain lines and laid lines, these are the fingerprint of the deckle, or frame, on which the paper was laid. Sometimes a wire design was stitched into the deckle to yield a watermark, where the raised wire would result in a thinner area, appearing lighter on the finished product. Machine made paper may have watermarks as well, and the crisscross pattern, while not an inherent artifact of the process, may be mimicked.

Photograph of watermark on Alturas map, circa 1824.
Watermark on Alturas map, c1824. The mark is in the form of a trumpet within a crest above the letter M. Chain lines run top to bottom, laid lines right to left. (Photo: own work)

Map collectors, myself included, usually devote our attention to subject of the subjects of maps without noticing the paper they are printed on. This is too bad. These old papers are marvelous works of art and science in their own right.

© Peter Roehrich, 2016.

Leaving a Mark

Have you held a crisp banknote up to the light to see a President or Monarch peering back at you, or did you notice a crest or a maker’s name on a piece of high-end stationary? Watermarks add beauty, security, and a physical link to the maker.

Watermarks are areas in the paper that are thicker or thinner, thus transmitting light differently than, the the surrounding paper. The term watermark refers to its application while the paper is wet. (Note that many modern security papers, such as checks and prescription pads, carry artificial watermarks; these are applied to the surface of the paper and are not the same as those found on antique papers.)  The first watermark dates to 1282 Italy. When making paper in, say, 1824 (see the example below), a slurry of cotton fibers from pulverized rags was poured over a wire mesh, pressed, and dried–this is termed laid paper. As the cotton pulp was pressed against the mesh, it would assume the pattern of the wire mesh in reverse; these papers take on characteristic chain lines and laid lines. Chain lines run across the mould, parallel to the short side, and laid lines run the length of the mould, spaced more narrowly than laid lines (these are not a watermark, they are an artifact of paper making, but can be used in identifying the paper). Any additional wire placed on the mesh would leave a corresponding thin area on the dried paper.

Photograph of watermark on Alturas map, circa 1824.
Watermark on Alturas map, c1824. The mark is in the form of a trumpet within a crest above the letter M. Chain lines run top to bottom, laid lines right to left. (Photo: own work)

The laid paper used for Alturas (to be discussed in a future post), has chain lines running top to bottom and laid lines running left to right (ignore the sharp black lines, these are part of the image on the page). These lines can be identified be the space between them–chain lines are relatively far apart, laid lines much closer together. An ornate watermark of a trumpet inside a crest above the letter M sits on one half of the sheet of paper. What is the crest? Perhaps indicative of the paper maker. Maybe the M indicates the page size. As I use online databases to investigate the origin of this paper I will keep you apprised.

© Peter Roehrich, 2016.