- CALENDERED Paper which has been smoothed and polished between sets of rollers called a calender; this process is usually done at the dry end of a paper making machine. CALIPER See thickness.
- CARBON PAPER A thin tissue paper coated on one side with colouring agent or carbon black which is transferred to a sheet of paper underneath when pressure in applied.
- CARBONLESS COPY PAPER This consists of two sheets of paper; the underside of the top sheet is coated with colourless dye in minute gelatine capsules; the underneath sheet is coated with a reactive chemical which turns blue or black when mixed with the colourless dye; pressure from a pen or typewriter on the top sheet causes the gelatine capsules to break, the dye and chemical mix and the blue or black copy appears on the bottom sheet.
- CARTON A container usually made of relatively thin carton or folding board, but sometimes partially or totally of plastic; it is delivered by the carton manufacturer to the user in either flat or collapsed form.
- CARTRIDGE PAPER Slightly rough coated or uncoated printing surfaced paper used for a variety of graphic purposes such as envelopes. The name comes from the original use for the paper which was for forming the tube section of a shotgun shell.
- CASES, CORRUGATED Large boxes made of board which are used as containers for packages; cases are mainly used for transit and storage purposes.
- CAST COATED A method of dxying coated paper by contact of the freshly coated surface with a highly polished chromium plated heated metal surface.
- CELLULOSE WADDING A crêped web or sheet of open formation made of cellulose fibres and comprising one or more plies of light-weight paper.
- CHAIN LINES Spaced lines at right angles to laid lines occurring as a watermark in paper.
- CHAIN WELTS (CHAIN MARKS, ROPEMARKS) Defect in reels due to variations in thickness across the width, resulting in the slack areas assuming a chain-like pattern around the periphery. CHALKING The ready removal, in the form of a powder, of an insufficiently bound layer of pigment on the paper surface resulting from the absorption into the paper of too high a proportion of the vehicle of an ink.
- CHEMICAL OXYGEN DEMAND (COD) This measures the oxygen demand caused by all impurities in the water when oxidising a sample with a strong oxidant. (c.f. BOD).
- CHEMICAL PULP See pulp.
- CHINA CLAY Natural mineral, consisting essentially of hydrated silicate of alumina, used as a filler or as a component in a coating slip.
- CHIP BOARD A cheap board grade usually manufactured from the lower grades of wastepaper.
- CHROMO A term used to describe both papers and boards used
- for subsequent brush coating. The various qualities are determined both by the actual grade of base material used and the quality of the coating, which may be gummed. Coating may be applied to one or both sides, depending on end use.
- COATED PAPER OR BOARD Material coated on one or both sides with a mixture of china clay, latex and other loadings to fill up surface pits and improve the printing surface. The process can be accomplished either on-line on the paper making machine or away from the paper making machine as a separate operation. There are a variety of coating methods, these include: roll coating, blade coating, air-knife coating and brush coating, or combinations of these types. A very high quality form of off-machine coating is cast coating.
- COATING (MINERAL) A layer of minerals applied to one or both sides of paper or board to improve brightness, gloss and printability; the mineral most often used is china clay, hydrated aluminium silicate, but calcium carbonate and titanium dioxide are also used; the coating is held together and stuck to the paper by a binder.
- COCKLE Local deformation of a sheet of paper due to unequal shrinkage giving it a slightly crumpled appearance.
- COD See Chemical Oxygen Demand
- COLLOTYPE A planographic printing process capable of producing high fidelity continuous tone colour reproductions, I.e. no screen is used in producing the negatives from which the plates are prepared.
- CONDITIONED PAPER Paper which has been treateo in the mill by exposure to hot, moist air to increase the moisture content of the paper to what is considered to be an optimum level for flatness and stability.
- CONTAINER BOARDS These boards are.made to provide a variety of product containers and are made from waste materials. They may, however, be lined with bleached or unbleached kraft, or other papers, depending on end use. Some of these boards may also be treated with plastics to provide special characteristics.
- CONTINUOUS STATIONERY A grade widely used on modern high-speed accounting and similar machines. The paper is supplied in reel form and along with the printing process many finishing techniques can also be used, such as perforation and special folds. A particular use is for invoices, statements and similar documents, when it is normally fan-folded.
- CONTINUOUS TONE An image in which tonal gradation is produced by changes in density.
- CONTRARIES Unsuitable material found in wastepaper which must be removed from the pulp before making it into paper, e.g. paperclips, string, plastics.
- CONVERTER A finn that specialises in converting reels and sheets of paper and board into packaging or finished goods for sale to the public.
- COOKING Treatment of fibrous raw material by heat in the presence of water, usually with added chemicals.
- COPIER PAPER Lightweight grade of good quality, used for copying correspondence and documents. May be glazed or unglazed. Most copier papers are laser compatible and special grades are made for colour copying.
- CORRUGATED FIBREBOARD Board consisting of one or more sheets of fluted paper stuck to a flat sheet of paper or hetween several sheets. The following are the main classifications:
- Single face corrugated fmbreboard. Board consisting of one sheet of fluted paper stuck to one sheet of facing.
- Single wall corrugated fibreboard (also known as double faced). Board consisting of one sheet of fluted paper interposed between and stuck to two facings.
- Double wall corrugated fibreboard (also known as double-double faced). Board consisting of two sheets of fluted paper interposed between and stuck to three facings.
- Triple wall corrugated fibreboard. Board consisting of three sheets of fluted paper interposed between and stuck to four facings.
- COUCH That section of the wet end of the paper or board machine at which the wet web leaves the vat machine cylinder or Fourdrinier wire part or other forming surface.
- CREPING Operation of crinkling paper from a roll or cylinder in order to increase its stretch and softness. This process may be earned out on or off the paper making machine. Two types are recognised:
- Dry crêping An on-machine operation carried out on a dried web.
- Wet crêping On or off-machine operation carried out on a wet or partially dried web.
- CROSS DIRECTION The direction in the plane of the sheet, at right angles to the machine direction (q.v), in a sheet or web of paper; the set expansion coefficient of paper is about three times as much in the cross section as in the machine direction.
- CTMP See Thermo Mechanical Pulp.
- CUTTING AHEAD Operation of slitting and cutting watermarked paper without regard to where the design falls in each sheet. The design(s) may fall in different places in successive sheets and some may be cut.
- CURlING TO REGISTER Operation of slitting and cutting watermarked paper so that the design falls approximately in a given position in each sheet.
- DAMPING The process of applying water to the lithographic plate on a litho printing machin~. Also the application of moisture to paper in preparation for a subsequent process, e.g. supercalendering.
- DAMPING ROLLER The roller on a printing machine which applies the moisture directly to the printing plate.
- DANDY ROLL The roll on the wet end of a paper making machine which is covered with a woven wire and carries a design to form a watermark iii wet pulp.
- DECKLE See Machine Deckle
- DECKLE FILL See Machine Fill
- DE-INKING The removal of printing ink and mechanical impurities by flotation and/or washing pulped wastepaper before it is recycled.
- DIMENSIONAL STABILITY Ability of a paper to retain its dimensions and its shape (a) despite changes in its moisture content under the influence of, for example, variations of the surrounding atmosphere, or (b) despite variations of the physical and mechanical stresses during printing and converting operations or use.
- DISSOLVING PULP Highly purified chemical pulp intended primarily for conversion into chemical derivatives of cellulose.
- DOCTOR A blade-like device which rests on the upmnning surface of a roll in order to keep it clean by removing any foreign matter adhering to the roll.
- DOUBLING The appearance on the printed sheet, locally, of two non-coincidental images obtained at one impression. DRIERS Substances, generally metallic compounds, added to an ink to increase the rate of drying by catalytic action.
- DRY END The part of a paper making machine where the paper passes through steam-heated drying cylinders.
- DRY OFFSET A method of printing, as in the offset lithographic method, but from a relief plate, and without the use of fountain solution.
- DUCT The trough on a printing machine, usually including an adjustable blade, which contains the supply of ink and by means of which the ink is presented to the duct roller.
- DUCT ROLLER The cylinder in the duct of a printing machine which, in conjunction with the adjustable knife blade, regulates the amount of ink applied to the feed roller.
- DUMMY An imprinted representation of the text pages of a book made by suitably folding and collating sheets of the intended quality and grammage of paper so that an idea may be formed of the general appearance and thickness of the ultimate book.
- DUPLEX CUTTING The operation of converting a web of paper into sheets on a cutting machine equipped with two cross-cut knives so that two different lengths of sheet can be cut simultaneously.