Papermaking

(Excerpts from ART HARDWARE: The Definitive Guide to Artists’ Materials, by Steven Saitzyk © 1987)

PAPERMAKING begins with the process of breaking down plant materials until individual cellulose fibers are obtained and are then suspended in water. A sheet of paper is formed by passing a screen through the suspension so that the individual fibers collect on the screen. The sheet of paper is then transferred to a mat where it is allowed to drain and dry. Pressure is often used to speed the process or to impart a particular finish.

The type of paper obtained can be influenced dramatically by such factors as the variety of plant material used, how the plant materials are broken down into fibers, how small the cellulose fibers are, the kind of screen used, how the screen is passed through the suspension, the kind of mat on which the sheet is placed, and whether the sheet is pressed. Other factors that influence paper variety are the use of chemicals, the addition of fillers or brighteners, the way in which the sheet is dried, and the polishing of the sheet’s surface. All these variables make it possible to produce almost unlimited styles of paper. In the Orient, one can find more than a hundred varieties of paper made with the same plant material where the only differences in its manufacture are the way the screen is passed through the suspension and the average length of the fibers.

Handmade paper is often the least complicated method of papermaking. This method is so labor-intensive, however, that the cost of using the best plant sources often pales by comparison. Therefore cotton and rag fibers, which require little or no special treatment-chemical or mechanical-to reduce them to workable fibers, are commonly used. Today, sheets of cotton linters, made from the leftover short fibers collected from the cotton gin, are added to water and beaten in a machine similar to a blender. The level of concentration of fibers helps to determine the thickness of the paper. The suspension is transferred to a vat through which a flat, rectangular wire or bamboo screen can be passed to form the sheet. The fiber-laden screen is drained and the wet paper is often pressed before it is allowed to dry.

In mouldmade paper, the person holding the screen is replaced by a rotating screen cylinder, which forms a continuous sheet of paper. The individual sheets are produced by passing a stream of air or water through the wet sheet. Mouldmade paper is considered half handmade and half machine-made because people are still used to create the suspension of fibers as well as in the pressing and drying of the individual sheets. The cost of materials becomes more significant and occasionally results in the use of cheaper raw materials. Such materials require refining before use, as well as chemical additives to improve their appearance, all of which complicates the papermaking process.

The production of machine-made paper involves little human contact until the paper is purchased. The materials are the most significant cost factor in this type of paper production. Elaborate chemical and mechanical processes are often used to change poor-quality raw materials into a useful piece of paper. First, impurities are removed; then the chemicals used to purify the raw materials must be removed or neutralized. Often such additives as sizing and optical brighteners are required. Then a rotating cylindrical screen pulls the fibers from the suspension to form a continuous sheet of paper. Finally, this sheet is pressed and dried by other steel rollers. For some types of paper like bristol, additional sizing is added before drying and the surface of the paper is polished after drying. The primary disadvantage of machine-made paper is that most varieties are of low quality. The advantages of machine-made paper include price, the availability of some varieties, such as hard-surfaced bristol and paper boards, which could not possibly be made by hand, as well as the ability to produce large quantities.