Glossary of Papermaking Terms

Abaca - plant more commonly known as manila hemp.

Abrasiveness - property of the paper surface.

Absorbency - capacity of the paper to absorb liquid.

Acid free - paper free from any acid content or other substances likely to have a detrimental effect on the paper.

Agitator - a revolving paddle used in stuff chests or vats.

Air-dried - term applied to machine-made paper which is dried by being passed over hot air drums.

Air-knife - a thin flat jet of air acting as a doctor blade to remove excess coating from a wet sheet.

Alum - aluminium sulphate, added to gelatine in the sizing of paper to stabilise the gelatine.

Apron - sheet of oiled cloth, leather or rubber which bridges the gap between the breast box and the moving wire on a Fourdrinier machine.

Ass - curved wooden post on the corner of the vat where the mould is rested after forming the sheet.

Back - marks left in a sheet of hand made paper where it has been dried over ropes.

Badger - term applied to a residue of pulp remaining in the vat after papermaking is completed.

Bamboo - now rarely used for the production of paper, the fibres are short and needle shaped.

Beater or Hollander - introduced mid seventeenth century and superseded the method of preparing pulp by hammering or stamping the rags.

Beater roll - cylinder or drum set with knives set against a bedplate to cut up rags in a beater trough.

Beating - process of reducing raw materials to a fibrous state in the production of pulp.

Bedplate - in a stamper it is a flat plate of iron in the bottom of the trough against which rags are pounded. In a Hollander it has ridges or knives and acts with the beater roll.

Bleach - chemical used to whiten paper pulp, often a chlorine solution.

Board - thick sheet of paper, either homogenous or made from several layers of paper pressed or glued together.

Board machine - similar to cylinder mould machine but has from two to seven cylinder moulds in line to form multi-ply boards.

Breaker - reduces rags to smaller pieces for beating in  a Hollander.

Breast box - part of the papermachine from which the pulp issues onto the moving wire.

Bridge - platform across the vat.

Broke - un-saleable flawed paper, usually repulped.

Brown-white - papermakers description of papers made from blends of white and coloured linen rags, and usually having some addition of hemp or jute fibre derived from rope.

Calcium carbonate - loading agent or filler.

Calender - set or stack of rollers at the end of the papermachine to smooth paper, may have heated rolls. See also Super-calender.

Calendering - process of pressing to smooth or glaze a sheet of paper during the finishing process.

Cardboard - thick stiff paper produced by pasting several layers of paper together.

Cartridge - originally used for making cartridges, later used as a strong wrapping paper and as an artists paper.

Cast paper - form of paper made by pouring pulp into a specially constructed mould.

Cellulose - basic substance of paper manufacture derived from plant tissues.

Chain lines - the more widely spaced watermark lines across the narrow way of a sheet of paper. Caused by the wires used to hold the laid wires together.

China clay - fine clay used as a filler.

Chemical wood pulp - wood reduced to pulp by a chemical process, e.g., with caustic soda or bi-sulphite of lime. See also Soda process.

Coating - mineral substances such as china clay applied to the surface of paper to make it more suitable for some methods of printing.

Cold pressed - surface quality of a sheet of paper made the same way as a Not surface.

Contraries - unwanted pieces of materials which have become embedded in a sheet of paper.

Cotton - source of fibre for papermaking, usually in the form of linters or rags. The fibres are strong and flexible and suited to the production of fine papers.

Couch - action of transferring sheets of newly formed paper from hand moulds to felt blankets.

Couch rolls - rolls at the end of a Fourdrinier machine to transfer the paper from the moving wire to a felt blanket.

Coucher - person who transfers newly formed sheets of paper from hand moulds to felt blankets.

Cover - wire surface of a hand mould through which the water drains, can be made of laid or wove wire, also the surface of a dandy roll.

Cracking - breakline occurring where sheets of paper are folded.

Cross - T shaped wooden tool used to remove paper from ropes in a drying loft.

Curing - allowing the paper to mature before sale.

Cylinder - term indiscriminately applied to various kinds of rolls or drums on papermachines. More particularly the steam heated cylinders for drying paper.

Cylinder mould machine, cylinder machine - invented by John Dickinson in 1809 and has a cylinder covered with a wire through which the water drains, leaving the pulp on the surface. The cylinder is partially immersed in a vat of pulp. It has been developed into board machines and machines for making paper with complex watermarks.

Dandy roll - light skeleton roll or cylinder covered with wire which presses gently on the paper while still wet. It helps to improve the formation of the sheet by gently pressing the top surface and can be used to impart a laid or wove look-through. Also used to impress a watermark into the top surface of paper by images attached to the roll.

Daphne - plant known as the 'Nepal paper plant' used as a source of fibre for papermaking.

Deckle - on a hand mould is the removable frame which retains the pulp on the cover while the water drains through. On a Fourdrinier machine, the deckle strap performs the same function on the moving wire.

Deckle edge - slightly wavy line to the edge of handmade paper, formed by a slight thinning of the edge of the sheet by pulp creeping under the edge of the deckle during forming of the sheet.

Deckle slip - strip of wood fixed to the underside of the deckle to stop the pulp from creeping.

Devil - machine for removing dust and dirt from rags or esparto grass (also called a willow)

Digester - vessel in which wood chips, rags or esparto grass are boiled with chemicals. It can be stationary or revolving, horizontal or upright, cylindrical or spherical.

Disc refiner - machine with rotating ribbed discs or plates which beats out pulp for papermachines.

Dished - stack of paper lying concave rather than flat.

Doctor - thin metal blade which scrapes off excess liquid or fibres off a roller to help maintain a smooth surface.

Double-faced mould - mould with a secondary supporting wire layer underneath the forming surface. Developed towards the end of the eighteenth century for wove moulds, also began to be used for laid moulds by the end of the eighteenth century.

Dry cylinder machine - is one where pulp is poured onto the surface of the cylinder so that the water drains away through the cover on the cylinder.

Dry end - term for the drying section of the papermachine consisting of the drying cylinders, calender, reel. etc.

Dry pressing - various pressing sequences applied to sheets after drying.

Drying loft - large airy room in which sheets of hand made paper are hung or laid to dry.

Duster - mechanical device, usually a revolving wire mesh drum, for opening out rags etc. and for getting rid of dirt.

Edge chains - extra chain lines running on the outer edge of both short sides of the mould for extra strength.

Embossed watermarks - see Shadow watermarks.

Embossing - form of printing to produce a raised impression or pattern on the surface of a sheet of paper.

Engine - originally a term applied to any machine but in a papermill particularly to the Hollander beater.

Engine-sized - paper to which the sizing was added during the beating stage.

Esparto - grass used for papermaking, the fibres are short and smooth, esparto paper has an even texture, softness and elasticity.

Felts - material woven from either cotton or wool with a raised surface which supports the wet sheet of paper during the stages of removal of water.

Felt mark - texture acquired on the surface of the paper from the felt.

Felt side - the side of the paper in contact with the felt after forming, opposite to the wire side.

Fermentation - old method of preparing rags for the beater of letting piles of wet rags heat up and begin to rot.

Fibre - fibres for papermaking, can be animal (e.g. wool or hair), mineral (e.g. asbestos) or plant. Plant fibres are the most important group, the important constituent being cellulose which is extracted from a variety of plants. Suitable plant sources can be grouped into several types: 
    Seed hairs, e.g. cotton
    Bast fibres from the inner bark or stems, e.g. linen, hemp, jute, ramie, mulberry
    Leaf fibres, e.g. esparto and manila
    Grasses, e.g. straw, bamboo
    Wood, usually softwoods such as spruce, fir or pine, but can be hardwoods. 
    See chemical, mechanical and thermo-mechanical pulps.
Plant fibres can be extracted from the plant itself or from secondary sources such as rags.

Fibrillation - the act of breaking up the surface of cellulose fibres during the beating process.

Filler - material added to the beating stage to fill in the pores of the fibre, producing a harder surface.

Finish - term used when describing the nature of the surface of the sheet.

Finishing - process of imparting the final surface to the sheet.

Flong - board used for forming stereotype moulds.

Foils - tapered strips of plastic fitted under the moving wire of a Fourdrinier machine to scrape off excess water and drain the sheet more quickly.

Form - old name for the mould.

Forming - the action of making a sheet of paper by dipping the mould into a vat of pulp, the water drains through the cover leaving the pulp on the surface.

Fourdrinier - name applied to the papermachine  after the Fourdrinier brothers who financed its early development. It produces a continuous web of paper and was developed by Bryan Donkin from the original invention of Nicholas-Louis Robert.

Free - pulp from which water will drain easily when on the mould.

Furnish - raw material from which paper is manufactured, particularly the fibre or blend of fibres.

Gampi - Diplomorpha spp, plant used for papermaking, the fibres are long and thin and difficult to fibrillate.

Gelatine - nitrogenous constituent of skin, bones, and hooves of animals, used as a size added to the dry sheet, has the added effect of strengthening the surface of the sheet.

Glaze - gloss or polish on a sheet of paper. See also Plate glazing.

Grain - alignment of fibres in a sheet of paper caused by the flow of the web of wet paper in cylinder or Fourdrinier machines.

Grinder - machine used to prepare mechanical wood pulp, consisting of a revolving grindstone against which the debarked logs are pressed to disintegrate them.

Ground wood - pulp produced by grinding wood.

Half stuff - partially broken or beaten fibres for papermaking. See also Stuff.

Hemp - Cannabis sativa, one of the oldest fibres recorded in use in papermaking, the fibres are strong and inclined to split in the beating process.

Hollander - see Beater.

Hog - wooden paddle used to keep the fibre in suspension in the vat, later replaced by a mechanical paddle in the base of the vat.

Hot pressed - one of three traditional finishes of hand made paper. Originally produced by pressing the paper between hot metal plates, later by plate glazing.

Hydration - process of take up of water by the fibres through crushing and fibrillation during beating.

Hydropulper - vat with a machine driven agitator or cutter used to reduce fibres to pulp and aid hydration.

Insides - the best paper regardless of type, the sheets used as the inside quires of a ream, the paper being packed with the best paper protected by lower quality paper top and bottom of the ream, the outsides.

Intermittent board machine - produces thick sheets of board by winding the paper as it comes from either a Fourdrinier or a cylinder mould machine onto a roller. When sufficiently thick the web is cut along the length of the roller and pulled off.

Jordan - machine for reducing or making finer the stock or pulp before it passes to the papermachine. It has a cone set with knives around its circumference which rotates within another also set with knives. Invented by J Jordan, Hartford, Connecticut, USA in 1859.

Jute - Corchorus capsularis, plant source of fibre, the fibres are strong and do not fibrillate or bleach easily.

Kaolin - fine white clay used as a filler.

Knots - small lumps of badly beaten or twisted fibres in the pulp.

Knotter - appliance with vibrating screens for removing knots or lumps from the pulp.

Kollergang - German name for an edgerunner used in pulping materials in papermaking.

Kõzo - Broussonetia spp, several species of the paper mulberry used in papermaking, the fibres are long and sinewy.

Laid lines - close light lines in laid paper formed by the laid wires of the laid mould or dandy roll.

Laid papers - those which, when held up to the light, have a ribbed or lined effect due to the paper being made on a mould made with a cover of closely placed parallel laid wires to form the sieve through which the water drains.

Laid mould - mould made with close fine laid wires fastened to wider spaced stronger chain wires running at right angles producing a paper with a slightly ribbed surface to one side of the paper.

Laminated paper - two or more sheets of paper couched together directly on top of one another.

Layer - person who separates the sheets of hand made paper from the felts on which they have been pressed.

Lignin - unwanted part of woody plants, can cause degradation later in the life of the paper.

Linen - Linum usitatissimum, term covers either flax or linen as a source of fibre, often in the form of rags. The fibres are hard and fibrillate easily.

Linters - three grades of cotton fibres obtained from the cotton plant after the ginning operation and used in papermaking: first cut or lint, mill cut and second cut. The fibres are short and do not need much refining.

Liquor - general term for chemical solutions, but in paper making chiefly used for alkaline solutions.

Litress - kind of smooth cartridge paper made in two sizes, Royal and Foolscap, used for drawing.

Loading - non-cellulose material added to the pulp, e.g. smalts added to rags to make them appear whiter or china clay added to bulk up the fibre and act as an aid to ink retention.

Look-through - structural appearance of a sheet of paper observed when viewed by transmitted light.

Louvres (or luffers) - shutters in the drying loft allowing circulation of air.

Macerate - bruising of fibres during the beating process.

Manila - plant also known as 'abaca', the whole plant is used for papermaking and yields several qualities of fibre.

Maturing - see curing.

Mechanical wood pulp - pulp prepared by purely mechanical means, e.g., by grinding logs of wood.

M G or Yankee machine - has a single highly polished steam heated drying cylinder to which the sheet of paper adheres as it dries and receives a smooth surface on the cylinder side of the paper.

Millboard - heavyweight boards made from hemp and flax fibres and/or fibre refuse.

Mitsumata - Edgeworthia spp, plant used as a source of papermaking fibre, the fibres are fine and relatively short.

Mould - rectangular wooden frame covered with either a laid or wove wire surface used for forming sheets of paper by hand.

Newsprint - name for paper used for printing newspapers, the cheapest type made.

Not - traditional paper finish, slightly rough and unglazed, produced by pressing wet paper against itself after the first wet press.

Opacity - quality of a paper related to the amount of light that can be transmitted through its surface.

Outsides - second quality paper used top and bottom of a ream to protect the best quality paper, the insides.

Pack or wad - may be either the pile of wet sheets assembled by the layer after separation from the felts or a small number of sheets piled up ready for glazing.

Paper-hanging - obsolescent term for wallpaper.

Pasteboard - general term for cardboard formed by pasting fine papers to either side of a middle of inferior quality paper.

Picker - person who examines finished paper for defects.

Picking - property of paper to release surface fibres during printing operations.

Plate glazing - method of producing a smooth surface on sheets of generally hand made paper by placing them between polished plates of zinc or copper and passing the pack back and forth with slight friction between pressing rollers.

Plate paper - paper designed for copperplate printing.

Post - term applied to a pile of sheets, normally 144 but varying in number, of wet pulp, fresh from the mould, just made into paper couched with alternate felts and ready for pressing.

Potcher - one of a series of beaters or engines used in washing and preparing pulp, especially applies to esparto.

Potching stick - used to move pulp around in a beater or vat.

Presse pâté - machine almost identical to the wet end of a Fourdrinier used to turn wood pulp into sheets which can be transported to another mill for making into the final paper.

Pressing papers - rag and rope based papers or boards, sometimes heavily glazed, used for pressing or resurfacing woollen cloth.

Printings - papers designed for letterpress printing.

Pulp - the aqueous stuff containing disintegrated cellulose fibre from which paper is made.

Quire - originally a quantity of twenty-four sheets of paper, now measured at twenty-five sheets.

Rags - formerly the principal raw material for making paper, now rarely used except for very high quality papers. Could be linen or cotton but by association also includes jute, sailcloth and hemp ropes.

Ramie - Boehmeria nivea, plant commonly referred to as 'China grass' used as a source of fibre for papermaking.

Rattle - sound produced by shaking a sheet of paper indicating its hardness.

Ream - term used for a quantity of sheets of paper, traditionally twenty quires (480 sheets) of paper but could vary with the type of paper. Now consists of 500 sheets.

Ream wrappers - sheets of coarse paper used to wrap a ream of paper.

Reel - general term for the revolving frame or drum which receives the paper coming off the machine.

Refining - was originally beating out any lumps left in the pulp before it passed to the papermachine but is now used for the final beating of wood pulp. See Disc refiner.

Resilience - property of paper that allows it to return to normal after distortion.

Retree - sheets of paper with minor faults.

Retting - term applied to the process of soaking flax in water to rot the hard stems to ease the process of beating into fibres. The process can also be applied to rags. See fermentation.

Ribs - thin bars of wood which support the wire cover of a mould, normally across the narrow way and in a laid mould support the chain lines.

Rosin - used in the sizing of paper, usually as an engine size but occasionally as a tub size.

Rough - traditional paper finish, formed by the weave of the felts during the wet press.

Rough shake - used to describe a sheet of paper in which the fibres are distributed at random, as in hand made papers.

Salle - room in the paper mill where sorting, curing and packing of paper took place.

Seconds - term for imperfect sheets. See also retree and outsides.

Shadow watermarks - formed on a woven wire cover by pressing it into higher or lower areas to form a pattern. The paper in the lower areas is thicker and in the higher areas is thinner. When looked through this produces dark and light areas in the watermark. Portraits and pictures can be made with this process and are often used in security papers. Also sometimes known as chiaroscuro watermarks.

Shadow zone - thicker area in the sheet of paper formed either side of the ribs on a single-faced mould by the water being drawn out and attracting more fibres.

Shake - sideways movement of a hand mould by the vatman or the wire of a papermachine to interlock the fibres whilst still suspended in the pulp.

Sheet - piece of paper or board, generally rectangular.

Shives (or sheaves) - specks in finished paper caused by impurities in the raw materials.

Silurian - term for paper which has flecks in it, often material or threads.

Single-faced mould - mould on which the wire cover sits directly on the ribs.

Size - originally a solution of glue or gelatine but later any substance that reduces the rate at which paper absorbs water or ink. Can be applied by coating the finished sheet or by addition to the pulp before forming. See also tub-sized and engine-sized.

Sizing - process of treating the paper with size.

Slice - opening through which pulp is poured onto the wire of a Fourdrinier.

Slushing - first dispersion of raw materials in water by agitation.

Smalts - finely powdered cobalt blue glass used in loading.

Soda process - alkaline treatment of wood for the production of chemical wood pulp by digesting the fibres under pressure with a solution of caustic soda.

Spur - group of sheets (from 3 to 38) dried together as a wad in the drying loft.

Stamper - early machine for making pulp, consisting of several sets of large wooden hammers falling into mortars filled with rags. Superseded by the beater.

Stationer - originally a tradesman who had a station or shop, as distinct from an itinerant vendor, formerly a book-seller, or publisher, or both, but now only a tradesman who sells writing materials.

Stock - see pulp.

Strainer - screens to filter out impurities from the pulp.

Strawboard - cheap coarse board made on a multi-cylinder machine from incompletely cooked straw.

Stuff - paper stock or pulp ready for making into paper. See also half stuff.

Stuff chest - large supply tank with an agitator in which the stuff is stored before passing to the vat or machine.

Suction or vacuum boxes - placed under the end of the wire on a Fourdrinier to draw out the water from the pulp or paper passing over them.

Suction couch roll - perforated revolving bronze shell passing over a suction box which serves to further extract water from the sheet of pulp or paper.

Sulphate process - method of cooking wood chips generally in sulphate of soda to produce chemical wood pulp, introduced by Dahl in 1884.

Sulphite process - process of pulping wood with sulphurous acid in closed vessels at high pressure.

Super-calender - set or stack of rollers separate to the papermachine to smooth paper, may have heated rolls. See also Calender.

Tearing wire - thick wire fixed to a mould producing a thinner line of paper to facilitate tearing into two sheets. Can also apply to a cylinder mould.

Texture - surface of the sheet, can be altered at various stages of the papermaking process.

Thermo-mechanical pulp - made by heating chips of wood under pressure.

Titanium dioxide - loading agent giving a degree of whiteness and opacity to a sheet.

Trebles (or tribbles) - racks of drying ropes often covered with horse or cow hair, used to dry paper in the drying loft. May also be hessian screens used to dry paper flat.

Tub-sized - refers to sizing applied to paper by soaking it in a solution of hot gelatine and alum after it has been formed, pressed, dried and allowed to cure.

Twin-wire - name applied to duplex paper made on a pair of Fourdrinier machines but joined while still wet in so that the two wire sides come together producing a sheet with the outer surfaces the same.

Vat - originally the tank containing the stuff from which hand made paper was produced but later also applied to the tank in which the cylinder of a mould machine is partially immersed.