Glossary of Terms

Acid-free: Paper that is free from any acid content or other substances likely to have a detrimental effect on the paper or its ability to last over time (see pH).

Alkaline: Alkaline means “base.” Anything that is alkaline has a pH over 7.0, and is considered to be free of acids.

Archival: Paper that is not only acid free but also lignin and sulfur free. Most commonly used to repair and restore historic documents, the paper must be long lasting without causing deterioration to itself or other materials it may come in contact with.

Batik: A method of treating fabric or paper with wax before dyeing, so the treated area does not pick up color.

Bagasse: The fiber left over after extracting sugar from sugarcane.

Bamboo: A grass yielding a fiber used for papermaking.

Basis Weight: The weight in pounds of a ream of paper. Its metric counterpart is grammage, where mass per unit area is expressed in units of grams per square meter.

Bleach: A chlorine solution used to whiten pulp in papermaking.

Bonding Strength: The strength of paper or board to withstand layer-to-layer separation. It is the force with which a coating or film adheres to the surface of a sheet.

Bristol: A stiff, heavy paper whose caliper ranges upwards from 0.006”.

Caliper (Thickness): The average thickness of a single sheet as determined by measuring the thickness of different sheets and averaging the results.

Cast-Coated Paper: A coated paper with high gloss and absorptivity in which the coating has been allowed to harden or set while in contact with a mirror-like polished chrome surface.

Chain lines: In a sheet of paper, the lines that run perpendicular to the laid lines. In a paper making mould laid wires are woven together by very thin wire or silk threads; these threads from watermark lines, called chain lines, in the newly formed sheet.

Chemical Pulp: Pulp obtained by cooking the fiber source such as wood with solutions of various chemicals.

Chin colle: A paper college process in which sheets of paper are laminated together by the pressure of the etching press and glue. this process allows for layers of colored areas to be achieved without having to use separate plates.

Chiri: A Japanese term for mulberry bark, commonly used to refer to any paper with inclusions of mulberry bark.

Coated Paper: Any paper that has been coated with pigment and its binder with a coat weight of 7.5 g/m2 or higher.

Cockle (Crinkle): The formation of ripples, bulges, or warped spots out of the plane of the sheet caused by uneven moisture, tension during drying.

Corrugated Board: A composite paper product made by adhering Linerboard to both sides of a web of corrugated medium on a Corrugator.

Cotton: One of the most commonly used plant fibers in the making of western papers. Also called “rag” or linters.’ Cotton is the purest form of cellulose produced in nature and it requires the least amount of processing before it can be used.

Cover Paper: A general term applied to a great variety of papers used for outside covers of catalogues, brochures, booklets, and similar pieces.

Deckle: The wooden frame that rests on top of a mould and defines the edge of a sheet during hand paper making.

Deckle edges: The feathered edges of a sheet caused where the pulp thins towards the edge of the deckle frame.

Die-Cut: A cut made with a special punching blade instead of with a conventional rotary knife.

Embossed Finish: Paper with a raised or depressed surface resembling wood, cloth, leather, or other pattern.

Esparto: A tough, wiry grass without cultivation in the semi-arid parts of Spain and North Africa. This fiber produces paper that is smooth and soft.

Finish: The finish of a sheet of paper denotes the condition of its surface. A high finish refers to a smooth, hard, surface. A low finish refers to a relatively rough, toothy surface.

Free (Wood-Free): Description for pulp or paper that contains nil or minimal mechanical wood pulp.

g/m2: Paper weight can be measured in variety of ways. The most accurate, and most common for decorative papers, is in “grammage.” whereby the weight measured in g/m2 refers to the weight in grams of exactly one square meter of paper. One gram is equal to .0022 pounds.

Grammage: The mass of a unit area of paper or board determined by the standard method of test: it is expressed in g/m2.

Hemp: An older name for abaca, manila hemp is related to the banana plant; its leaf fiber is often used in paper making. Not to be confused with true hemp-cannabis sativa, or marijuana plant.

Ink Jet Printing: Printing process of an image or text by small ink particles projected onto the paper surface.

Kozo: A long, rough fiber from the mulberry tree that produces strong absorbent sheets of paper; the most common fiber used in Japanese papermaking.

Kraft paper: Paper made substantially from any kind of sulphate (Kraft) pulp.

Kraft Pulp (Sulphate Pulp): Any pulp made by the sulphate process, whose cooking liquor is mainly a mixture of sodium hydroxide and sodium sulphide.

Laid paper: Paper with a prominent pattern of ribbed lines in the finished sheet. It is customary for the laid lines to run across the width and the chain lines to run from head to foot. The mould used to make laid paper has numerous narrowly spaced laid wires that are woven together by very thin wires or threads called chain lines.

Laser Printing: Xerographic printing where a modulated laser ray is projected on to a photoconductive cylinder or belt by a rotating mirror. The laser serves to produce the electrostatic latent image, which is developed with toners.

Letterpress: The process of printing from a raised inked surface with a plate.

Lightweight Paper: Papers having a grammage (basis weight) normally less than 40g/m2.

Lignin: The primary noncarbohydrate constituent found in wood; a polymer that functions as a natural binder.

Linters: The short fibers that cling to cotton seed after the first ginning. these cotton fibers are too short thread spinning or clothmaking, but are useful in making paper pulp.

Machine-made: Paper that is produced on a rapidly moving machine which forms, dries, sizes, and presses the sheet. this process forms an extremely uniform sheet.

Matte: Dull finish of coated paper. The coating is a special formulation and there is little, if any, calendaring.

Mechanical Pulp: Pulp, which has been prepared from wood primarily by mechanical, rather than chemical, means of separating fibers or fiber agglomerates from each other.

Mould: A flat screen with wire mesh onto which the deckle is placed during hand papermaking.

Mould made: A sheet of paper that simulates the look of handmade paper but is actually made by a machine called a cylinder mould.

Paper: A name for a range of fibrous materials in the form of a coherent sheet or web used for writing, printing, wrapping, packaging, decorating, etc.

pH [p(potential of H(hydrogen)]: In lay terms, the measure of availability of free hydrogen ions representing the balance between the acid and alkaline components of a material. 7 pH (pH neutral) represents a balance between acid and alkaline components; 0 pH is very acidic; 14 pH is very alkaline. (see acid free)

Rag Content: The proportion of natural fiber rag like cotton in a paper furnish.

Rice paper: A common misnomer applied to Asian papers, this term most often refers to any paper made from the mulberry tree family and is not actually made from any part of the rice plant.  It is said that mulberry paper got the name rice paper because it was originally used to make packets of rice. Translucent unryu papers, with strands of kozo/mulberry fibers (see unryu definition), are most commonly described as “rice paper”.

Salago: A wild shrub native to Philippines which is harvested in a manner very similar to mulberry. Limbs are trimmed, the bark is stripped off and inner fiber of the branch is boiled and beaten to make it less absorbent. The amount of sizing in or in a paper determines its resistance to moisture. The more sizing, the less absorbent the paper, and vice-versa.

Su: A flexible bamboo or reed screen used in Japanese papermaking.

Tissue Paper: Thin, soft paper made from strong cellulose fibrous materials and of a substance usually between 12 and 25 gsm.

Unryu: Meaning “cloud dragon paper” in Japanese, urynu is characteristic of paper containing strands of kozo fiber that are added to the mulberry paper to create contrast and texture. The lighter weight translucent unryu papers are most commonly referred to as rice paper.

Vellum Finish: A toothy finish, which is relatively absorbent for fast ink penetration.

Washi: From the Japanese wa, meaning “Japan,” and shi, meaning “paper,” washi refers to any Japanese paper, traditionally made or otherwise.

Watermark: Localized modification of the formation and opacity of a sheet of paper while it is still quite wet, so that a pattern, design, or word group can be seen in the dried sheet when held up to the light.

Wove paper: A type of paper with a smooth, even surface made using a mould with a fine wire mesh.