by Rhonda Farfan • Executive Vice President of Consumer Standards Emeritus
The making of paper
Paper is made of fibers that are interwoven together, usually in sheet form. The making of paper falls into 3 categories: handmade, mouldmade and machine made. Handmade papers are still made in much the same manner today as they were centuries ago, by scooping pulp from a vat onto a mould by hand. Mouldmade papers emulate handmade papers, but the cylinder-mould machine works on a larger and faster scale than the handmaking process. Cylinder-mould machine papers, though different than handmade papers, are often considered to be half handmade and half machine made. Machine made papers, made on a Fordrinier papermaking machine, are made and dried much faster than cylinder-mould papers, utilizing a different quality of pulp.
The following are some common terms used in papermaking:
Furnish – This describes the basic ingredients that make up the paper. Cellulose fibers from plants make up the furnish from which paper is made. The best papers are made from plants high in cellulose.
Beating – The process of treating fibers mechanically in water. During the beating process several things occur.
This beating process determines the strength, the bulk, the porosity, and the type of paper being made, depending on the ratios between the cutting, fibrillation and the hydration of the beaten fibers.
Types of papers
The majority of machine made papers are made from a mixture of fibers of hardwood and softwood, while papers made from fibers of cotton, linen, jute, ramie, and esparto are a different quality and more expensive.
- Cotton fibers yield a pure cellulose. Cotton linters and cotton rags are the types of material available to the papermaker from the cotton plant. Cotton linters are the principle fibers used in hand and mouldmade papers today. Cotton rags are longer, tougher fibers than cotton linters, but are rarely used in papermaking today. Papers that are described as "rag" papers may actually be cotton linters.
- Linen covers a variety of raw materials known as flax or linen. The long, tubular fibers impart a strong, smooth, silky feeling paper.
- Jute is a fiber which does not fibrillate or bleach easily. It is native to India and the Far East.
- Hemp from China, produces a hard, course paper.
- Kozo, Mitsumata, and Gampi are native papers of Japan. Kozo is a tough paper that retains its strength even when crumpled or folded. Gampi papers are translucent and tough. They have a wet strength and resistance to insects. Mitsumata is soft, smooth and glossy and also naturally insect resistant.
- Esparto grasses are leaf fibers which are used in the Far East. Grass fibers include bamboo, giant nettle, rice straw and rattan.
- Wood pulp is the material from which the majority of the world's current papers are made. Today there is a process designed to isolate the cellulose from the wood resins to produce "high alpha cellulose" which promises to be comparable to most rag papers in longevity.
Properties of Paper
- Permanence – For permanence, the fibers must be as pure cellulose as possible. Cotton is 100% cellulose, whether rags or linters. Wood pulp varies in cellulose content but high alpha wood pulp can be 93% cellulose, almost as pure as cotton. The fibers are shorter, however, so the characteristics differ. Many artists papers today are labeled acid free. These are generally neutral pH at the time of manufacture, but factors such as environmental conditions can affect this neutrality even before the artist purchases the paper, and afterwards. For this reason many papers have a "buffering" agent [an alkaline substance such as calcium or magnesium] added during the papermaking process to protect the paper.
- Surface or Texture – The surface or texture of paper varies according to the fibers, the beating, the drying process, or other factors. In general there are 3 terms used to describe the surface of hand and mouldmade papers.
- Rough paper – also called course, antique, felt, or irregular is a natural surface of handmade paper that has been dried without pressing or smoothing. Mouldmade papers are made rough by using rough felt.
- Not paper – also called cold pressed, dull, eggshell, matt, medium, regular, satin, slightly grained, unglazed, and velour, results from parting and repressing handmade sheets without felts. This surface is between rough and hot pressed.
- Hot pressed [HP] – also called glazed, high sheen, smooth, or super calendared, is either pressed between hot glazing rollers, passed through cold polished rollers, or polished with a smooth hard object [calendared].
Handmade papers may appear to have the same surface on both sides but there is a "wire" side and a "felt" side, or top side. With mouldmade and machine made papers the wire side is more porous than the felt side, has more grain, shorter fibers and less sizing. This two-sided quality of paper offers the artist a choice of textures on which to work.
- Edges – Deckle edges are slightly wavy edges found on handmade and mouldmade papers. A full sheet of handmade paper has 4 deckle edges. Mouldmade papers have 2 true deckle edges, on the sides.
- Weight – The weight of paper is traditionally measured in pounds weight per 500 sheets of a certain size paper. ·
- Color – The whiteness of paper varies according to the fiber color, cleaning, bleaching drying and sizing operations, etc. Bleaching has distinct disadvantages. Paper can yellow, become brittle, and deteriorate if traces of bleach are left on the fibers. During this century, there has been a tendency to artificially whiten papers using optical brightening agents. These initially produce a whiter sheet, but the color changes markedly over time and will yellow. This will not happen to paper made with the natural shade of the fiber.
Storing paper and tips for framing works on paper
- Temperature – Paper requires a temperature of 60 to 65 degrees Fahrenheit, and a relative humidity of above 30%, but below 70% [60% is ideal]. Conditions that are hot cause paper to become brittle and damp conditions cause mold, which feeds on sizing and fibers.
- Storage – Paper is best stored flat. Acid free boards should be place on top and bottom of the flat file to avoid migration of acids. Wooden flat files are better than metal for paper storage as they stabilize relative humidity, and do not rust. In case of fire, heat travels more slowly through wood than metal. Interleaving with acid free tissue between sheets of paper is also advisable.
- Framing tips
- Don't hang on an outside wall of a house without works on the back of the frame to allow air circulation behind the frame.
- Avoid hanging over radiator, fireplaces, and warm air vents, to prevent temperature extremes and dust particles.
- Avoid "uniframes" or "sandwich" frames that are clipped together without an edge. They allow pollutants and dust to get to the work.
- Don't allow the work to touch glass or plexiglass glazing. Either mat or use a spacer.
- Avoid non-reflective glass because moisture condenses easily behind it, causing mold.
- Use frames with high quality acid-free materials to combat migration of acids to the work.
- If your work is framed by a professional, be sure to specify the precautions you'd like taken.
It is important when buying paper to hold it to the light, to determine its hardness or softness, textures [both sides], and how much light it reflects. Talk to your art supplier, ask questions and write to the manufacturer, if necessary. Try out various kinds of paper. Knowing about paper will only enhance your pleasure in creating artwork on this versatile surface. The "paper of your dreams" may be the next one you try.
Source: Which Paper? By Silvie Turner, published by estamp, 204 St. Albans Ave. London W4 5JU