Useful Paper Terms
A Helpful User's Guide to Paper Terminology
Paper that contains no free acid. Acids have pH values below 7 (1-6). Alkalies have pH values above 7 (8-14). Specifications for an acid-free paper range from 6.5 to 7.
The state of a substance that contains acid. Paper becomes acidic from the ingredients used in its manufacture, from the environment or both.
An astringent crystalline substance used in rosin sizing to hold paper fibers together and responsible for introducing acid into the paper.
A term describing the use and collection of government or corporate documents. Agencies that govern large archives, like the Library of Congress, set standards for their curation, called "archival standards."
Refers to a group of fibers commonly used in Japanese papermaking, including flax, gampi, hemp, jute, kozo and mitsumata.
A process that neutralizes a paper's acidity over time by adding an alkaline substance, like calcium carbonate, at the pulp stage. Buffering helps reduce the acidity of paper over time.
Mildly textured surfaces produced by pressing the paper through unheated rollers. Generally considered to be a surface between rough and hot pressed.
1. Wood frame resting on or hinged to the edges of the mould that defines the edges of the sheet in handmade papermaking.
2. Strap or board on the wet end of a paper machine that determines the width of the paper web.
Natural, fuzzy edges of handmade papers, simulated in mouldmade and machine-made papers by a jet stream of water while the paper is still wet. Handmade papers have 4 deckle edges, while mouldmade and machine-made papers usually have two.
The degree to which paper retains its original qualities with use.
A grass from North Africa which makes a soft, ink receptive sheet (Basingwerk contains esparto.)
The slender, thread-like cellulose structures that cohere to form a sheet of paper.
Generic term to describe the nonoxidizing clays or minerals added to the pulp at the beater stage to improve paper density.
Term used to describe the cutting, sorting, trimming and packing of paper.
A bast fiber from the gampi tree used in Japanese papermaking to yield a translucent, strong sheet.
The European measure of weight for artists' papers. It compares the weights of different papers, each occupying one square meter of space, irrespective of individual sheet dimensions.
Direction in which the fibers of machine-made paper lie due to the motion of the machine. When machine-made paper is moistened, the fibers swell more across their width than along their length, so the paper tends to expand at right angles to the machine direction. Handmade and mouldmade papers have indistinguishable grain directions.
A sheet of paper, made individually by hand, using a mould and deckle.
A nearly pure form of wood pulp which has the same potential longevity in paper as cotton, linen or other natural fiber.
Smooth, glazed surfaces produced by pressing the paper through hot rollers after formation of the sheet.
The most common fiber used in Japanese papermaking, it comes from the mulberrv tree. This is a long, tough fiber that produces strong absorbent sheets.
Paper with a prominent pattern of ribbed lines in the finished sheet. It is accomplished in handmade paper using a screen-like mould of closely set parallel horizontal wires, crossed at right angles by vertical wires spaced somewhat further apart The same effect is achieved in machine-made paper with the use of a "dandy roll," positioned at the top of the wire in the wet end of the paper machine.
A general term for pre-processed pulp, cotton or wood, purchased in sheet form. Cotton linters are fibers left on the seed after the long fibers have been removed for textile use. They are too short to be spun into cloth but can be cooked and made into paper. Stiffer and more brittle than long-fibered cotton, linters produce a low-shrinkage pulp good for paper casting. They cannot produce a paper with the strength of cotton rag. Wood linters are called hardwood or softwood depending on grade.
A sheet of paper produced on a rapidly moving machine called the Fourdrinier, which forms, dries, sizes and smooths the sheet Uniformity of size and surface texture marks the machine-made sheet
A bast fiber used in Japanese papermaking that yields a soft, absorbent and lustrous quality.
The main tool for hand-papermaking, it is a flat screen that filters an even layer of fibers through it to form the sheet In western papermaking, it is accompanied with a wooden frame called a deckle.
A sheet of paper that simulates a handmade sheet in look, but is made by a slowly rotating machine called a cylinder- mould. The machine was introduced in England in 1895. No mouldmade are made in the U.S.
The degree to which paper resists deterioration over time.
A measure of the hydrogen ion concentration of a water solution and substance, denoting acid or alkaline. A substance with a value of 7 is considered neutral.
pH Neutral Paper
Paper made with any kind of pulp having a pH of 6.5 to 7.
A smooth surface found on paper that has been run under a calender machine one or more times.
A single web of paper, used by itself or laminated onto one or more additional webs as it is run through the paper machine.
A general term describing the beaten, wet mixture of stock used in making paper, whether its contents are wood, cotton or other fibers. Also called pulp finish.
Processed clippings of new cotton remnants from the garment industry for use in high quality papers.
Paper made from fibers of non-wood origin, including actual cotton rags, cotton linters, cotton or linen pulp. Rag papers contain from 2-100% cotton fiber pulp.
A common misnomer applied to lightweight Oriental papers. Rice alone cannot produce a sheet of paper. Rice-straw is only occasionally mixed with other fibers in paper- making. The name may be derived from the rice size once used in Japanese papermaking.
Heavily textured surfaces produced by minimal pressing after sheet formation.
Material, such as rosin, glue, gelatin, starch, modified cellulose, etc. added to the stock at the pulp stage, or applied to the surface of the paper when dry, to provide resistance to liquid penetration
A term for pulp made from wood. Depending on how it is processed for papermaking, it can either be acidic or neutral in pH.
A term applied to a paper whose surface has been treated with a sizing material after the sheet is dry or semi-dry.
A term applied to a paper that has been surface-treated and/or impregnated with a sizing material in a tub-size press.
A slightly rough or "toothy" surface on a sheet of paper. Waterteaf - A paper with little or no sizing, like blotter, making it very absorbent If dampening is desired, this paper can be sprayed with an atomizer.
Design applied to the surface of the paper mould which causes less pulp to be distributed in that area and results in the transfer of the design to the finished sheet
The continuous ribbon of paper, in its full width, during any stage of its progress through the paper machine.
The strength of a sheet of paper after it is saturated with water.
Paper with a uniform unlined surface and smooth finish, generally made on a European style mould with a woven wire surface. Most papers produced are of this type.
Why Cotton Fibers Make Excellent Paper For Artists
Fibers are slender, thread-like cellulose structures that cohere to form a sheet of paper. You can only see them with the aid of a microscope. Paper strength is dependent on the length, strength and character of these individual fibers. Paper quality is dependent on the nature of the fibers.
A cotton fiber is a single hair-like cell which grows from the end of the cotton seed. Eventually, it grows into a long, flat tube about 1" long and 1/1000" to 1/1200" thick. Within the growing tube is a central canal containing the juices which make up the fiber. These juices dry up when the fiber reaches maturity and the tube collapses and becomes twisted. This twisted formation gives the cotton fiber its flexibility, softness and bulk.
Cotton fibers are white, opaque and have no pores or cross markings, like wood fibers. Their ends are round and blunt Because of their unique shape, cotton fibers will not pack closely together during their formation as pulp. Instead, they interlock during the beating process, adding strength, flexibility and bulk to the subsequent paper sheet.
Wood fibers are shorter and wider than cotton fibers. While they sometimes have a slight twist, it is not as pronounced as in cotton fibers. Fibers from coniferous trees, such as spruce and pine, are longer, stronger and have more bulk than those from deciduous trees.
Two Common Misnomers About Paper
- 100% rag means the paper is neutral pH and permanent. 100% rag means only that the fiber content of the paper is composed of fibers of non-wood origin, including actual cotton rags, cotton linters, cotton or linen pulp. Other ingredients in the papermaking process, such as type of sizing, water quality and the exclusion of residual bleaching chemicals and acidic compounds all contribute to the paper's ultimate pH and its potential permanence. Many sulfite paper- those made from wood pulp- are also neutral pH and considered permanent True paper permanence is the joint responsibility of the papermaker, the artist and the curator. The three factors which most determine paper permanence are: ingredients, environment and curation. A paper does not have to be 100% rag to be pH neutral and potentially permanent.
- A paper must be buffered to be permanent. Due to the environmental conditions present in much of the world today, a paper that is pH neutral in manufacture is apt to grow more acidic with time, if there are no residual alkaline salts stored in it This is where buffering, the addition of an alkaline carbonate, can be helpful. Buffering introduces an alkaline reserve of 1-3%, thus extending the neutrality of the paper over time. A paper that is not buffered, however, may last just as long. This is because there are many factors in the papermaking process, the environment and in curation that can affect a paper's pH. Since paper permanence cannot be guaranteed, under most normal circumstances, it is best to select papers that fit a wide range of qualifications, including surface texture, color, absorbency, resilience, quality of ingredients and affordability.