Glossary of PaperMAKING TERMS

Abaca: Pronounced ah-be-KAH, Musa textilis. This Philippine species in the banana family is an important papermaking fiber also known as Manila hemp. The bast fiber from the stems makes a very strong paper that is used for making tea bags, and was originally used for making Manila folders and envelopes. When beaten for a long time it becomes very translucent.  

Acid Free: Archival paper that is neutral pH or slightly alkaline. Technically the paper is not completely “free” of acid, but the acidity is at a low enough level that it will not cause degradation.

Base Sheet: A sheet formed to support other layers of paper. For example, a freshly formed base sheet of thick cotton might become the “canvas” for multiple thin layers of pulp painting.

Bast Fiber: Type of plant fiber, mainly from the inner stalks of plants. Kozo, flax, hemp, and abaca are examples of bast fibers used in papermaking.

Beater: Also known as a Hollander beater, a seventeenth-century Dutch invention that is still in use today to macerate fibers into pulp by cutting or crushing fibers between the rotating bars of the beater roll and the stationary bars of the bed plate. The term “Reina beater” refers to a beater fabricated by David Reina of Brooklyn, NY. The term “Valley beater” refers to a test beater used by the machine-made paper industry. 

Beating: The physical or mechanical process by which fibers are cut, macerated, fibrillated, and separated in water, until they form a usable pulp. Common beating mechanisms include Hollander beaters, whiz mixers, blenders, and mallets.

Blowout: A papermaking technique for creating images. A stencil or object is used to protect portions of a freshly formed sheet of paper while the rest of paper is removed or “blown out” with water pressure.

Calcium Carbonate: A common chemical found in chalk, often abbreviated as Cal Carb or CaCO3. Added to pulp as a buffer that creates an alkaline reserve (making the paper slightly alkaline to withstand future contact with acidic materials, pollution, etc.).

Calendering: Flattening and smoothing paper mechanically by running it through a press or passing it between metal rollers.

Casting: Making relief forms or sculpture in-the-round with paper pulp or newly-formed sheets of paper. See also “laminate casting” and “pulp casting”

Cellulose: Chemically, a high-molecular-weight polymer (or chain) of glucose; the chief component of plant tissue. The attraction between cellulose molecules is the principal source of fiber-to-fiber bonding. Cotton, linen, abaca and other fibers contain generous amounts of cellulose and are ideal for papermaking.

Charge: Add pulp to a vat to replenish vat stock: “charge” a vat.

Cotton Linters: The coarser, shorter fibers left on the cotton seed after the long staple fiber has been ginned away for use in the textile industry. They are cut from the seed, cooked, and formed into pulp sheets. Cotton linters are low-shrinkage fibers and recommended for hand casting and forming base sheets for pulp painting, stenciling, etc. Cotton linters may be mixed with other stronger fibers such as abaca when more durable handling and folding is required.

Cockle: Distortion or ripples in a sheet of paper that occurs either in the drying process or when a sheet is rewet. 

Collaborator: At Dieu Donné this is a master papermaker who works with an artist and is intrinsically involved in the artistic process of creating work in the paper studio. Similar to a master printer in that the collaborator offers technical expertise to the artist that helps realize the artist’s vision. The artist and collaborator work together in the planning stages, and are usually both involved hands-on in the wet studio.

Couch: Rhymes with “smooch,” meaning to transfer a freshly made sheet of paper from the mould surface onto a dampened felt. From the French word “coucher” meaning to lie down or put to bed. Layering an additional sheet on top of the first is known as “double-couching.”

Deckle: The removable frame that fits onto the mould to contain pulp, which determines the size, shape, and edge of the sheet.

Deckle Box: A self-contained setup to make a single sheet of paper, as opposed to setting up a vat.

Deckle Edge: The natural, feathery edge of a handmade sheet of paper, which is created by small amounts of pulp running under the deckle.

Drying: Paper can be dried in various ways, including air drying (allowing to dry naturally), restraint drying in a forced air system (usually between blotters and corrugated cardboard under weight), or by brushing or pressing paper onto metal, glass, wood, or other another material.

Dye: A liquid colorant that chemically bonds to fiber. Dyes are soluble and penetrate fiber, while pigments are insoluble and attach to the outside of the fiber. Generally dyes need a mordant (fixative) to help them attach, whereas pigments use a binder. Pulp colored with dyes is generally more translucent than pigmented pulp, but dyes tend to be less lightfast.

Embed: To trap a material between layers of wet paper. For example, fabric might be embedded between two thin sheets of abaca.

Emboss: To impress a pattern or image into a sheet of paper while wet (or dry), generally using a press.

Felt: The material (traditionally a woolen blanket) onto which a newly formed sheet of paper is couched. The paper stays on the felt until it has been pressed. Many contemporary papermakers use sheets of pellon for this purpose, and leave the paper on them during the drying process.

Flax: Linum usitatissimum. The bast fiber from the plant is used for papermaking, and for making linen textiles (which can in turn also be processed into papermaking pulp).

Fiber: Cellulose-based material derived from plant matter that forms the basis of a sheet of paper. 

Formation Aid: A chemical or natural substance used to keep fibers in suspension in the vat (especially in Asian papermaking styles). It also can be added to pulp paint to improve flow.

Hog: the act of stirring up the slurry in the vat immediately prior to forming a sheet. 

Hydraulic Press: A type of press used in papermaking that goes straight up and down to squeeze out water and is powered by pressurized hydraulic fluid. A simple hydraulic press can be made using a car jack.

Hydrogen Bonding: The electrostatic attraction between hydrogen atoms in water helps to bring fibers together as the sheet is formed. As the final molecules of water leave the sheet, hydrogen bonds form between the fibers.

Kiss Off: When a sheet of paper that is still on the mould is unsatisfactory, the mould surface is lightly touched onto the surface of the vat, causing the pulp to fall back in.

Kozo: Broussonetia papyrifera, also known as paper mulberry. The main fiber used in Japanese papermaking. Kozo is noted for its long fiber length, which enables the papermaker to make very thin but strong and flexible sheets.

Laid mould: a type of mould that has wires across the surface to support the pulp in sheet forming. These wires impart a slight texture and watermark in the paper.

Laminate Casting: A sculptural papermaking technique in which sheets of paper are laid over a form and allowed to dry, taking the impression of the object below. Papier-mâché is a familiar form of laminate casting.

Methyl Cellulose: A powdered substance derived from cellulose that forms a viscous gel when mixed with water. Safe, pH neutral, and archival, it has many industrial and food grade uses. It is used as an adhesive or light sizing on dry paper. It can be added to wet pulp to promote fiber-to-fiber bonding in casting, or added to pulp-painting pulp to improve flow and handling.

Mould: A rectangular wooden frame covered with screen or laid wire upon which paper is formed and drained. The British spelling of mold, preferred by papermakers.

Overbeaten: High shrinkage pulp that has been beaten for a long time. Longer beaten pulps typically create more translucent, harder, more impervious sheets, which are prone to cockling.

Pellon: Brand name for a non-woven polyester material sold in fabric stores as interfacing and available in varying thicknesses. Can be used as a substitute for papermaking felts.

Post: A stack of newly formed sheets of paper between felts.

Pigment: Coloring matter in the form of insoluble, finely ground particles. Pigments attach to the outside of the fibers they are coloring, as opposed to penetrating like dyes. Generally, a retention agent is needed to keep the pigment attached to the fiber.

Pressing: Compacting freshly formed sheets to remove excess water and compress the fibers sufficiently so that the sheet can be lifted from the felt without falling apart. Usually done in a hydraulic press.

Pulp: The aqueous mixture of macerated fibrous material from which paper is made.

Pulp Casting: Laying dense, wet pulp into a mold or onto a surface, pressing it in, and extracting water with a sponge until the pulp is firmly compressed to the surface. A hydraulic press may be used to facilitate water removal when casting in rubber molds. When dry, the pulp is removed and takes the form of the surface upon which it was cast.

Pulp Paint: Very finely beaten pulp that acts like paint and can be pigmented in almost any color.

Rag: Woven fabric used for papermaking. The term “rag” or “all rag” properly describes a sheet made entirely from woven fabric. Today however, the term is sometimes used as a misnomer to describe paper made from cotton linters. 

Retention Aid: A cationic agent used to help pigment bond to fiber. A retention aid is generally necessary to keep color attached to the fiber, so that it will not wash away with the water in the papermaking process.

Rice Paper: A common misnomer for thin Asian papers usually made from kozo, but which might also be made from other fibers such as wood pulp. The origin of the term is not known, but it is inaccurate at best, and considered derogatory by many papermakers. Better terms are “Asian paper” or “Mulberry paper” if the content is largely kozo.

Sizing: Used to control absorption, ink bleeding, and durability of paper. Sizing can be added to the pulp (internal sizing) or applied to finished sheets (external sizing). Dieu Donné generally adds internal sizing (Hercon 100) to pulps.

Shake: The action of the papermaker when s/he dips a layer of pulp onto the mould and moves the mould in a front-to-back and side-to-side motion. The shake is important part of the papermaking process that helps the watery pulp slurry to settle evenly and causes the fibers to interlock well, creating a strong sheet of paper.

Vat: A tub or vessel that holds pulp for sheet-forming. 

Watermark: A pattern or image created in the papermaking process that is visible when the sheet is held up to the light. Watermarks are made by attaching a raised design to the mould surface, which creates thinner areas of the sheet when the pulp settles. Traditionally watermarks were made with thin wire, nowadays they can also be made using vinyl, 3D printing, or fabric paint on mesh.

Whiz Mixer: A device with a mixing attachment that hydrates pulp sheets or already processed pulps. It is not mechanically designed to beat rags into pulp.

Wove Mould: A type of mould with a fine wire mesh surface so that the rib lines of the mould will not show through in the paper. The wove surface is a later invention than the laid one.