glossary

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Absorbency: The ability of the paper to absorb fluids such as water or printing ink.

Acidification: The act or process of acidifying, or changing into an acid. Acidi fication is caused by acid depositions which originate from antropogenic emissions of the three main pollutants: sulfur dioxide (SO2), nitrogen oxides (NOx), and ammonia (NH3). Acid depositions have a negative impact on water, forests, and soil.

Adjustment (print): Regulation of the different print units on the printing machine in order to obtain a print proof which is the reference during the whole printing process.

Alternative energy: Alternative energy refers to energy sources that are not based on the burning of fossil fuels or the splitting of atoms. For example, solar energy, wind power and hydroelectricity.

AOX – Absorbable Organic Halogens: Absorbable Organic Halogens. AOX expresses the amount of organic chlorine compounds produced in effluent. AOX measures all chlorine compounds ie. both harmful and harmless (a sum parameter).

AOX – Absorbable Organic Halides: Measures the quantity of chlorinated organic compounds in mill wastes. It is also an indirect indicator of the quantity of elemental chlorine used in the bleaching process and the amount of lignin in the unbleached pulp before it enters the bleach plant.

Apparent Density: The apparent weight per unit volume. It is often calculated by dividing the basis weight by the thickness, though it must be recognized that the numerical value thus obtained depends on the definition of the ream. Consistent numerical values can be obtained by using in every case the basis weight in metric units (gsm) and the thickness in millimeters.

Bible paper: Woodfree, sometimes rag-containing speciality paper with a low grammage, mostly with a high filler content.

Binding: Converting of several signatures into a book.

Biochemical Oxygen Demand –BOD: Biochemical Oxygen Demand (BOD) measures the amount of oxygen that microorganisms consume to degrade the organic material in the wastewater.

Biodegradable: Biodegradable waste is capable of being broken down into non-harmful products by the action of living things such as microorganisms.

Black Liquor: Chemical residue containing lignin.

Blanket: Rubber (or similar) cloth covering the cylinder on a printing machine. The blanket conveys the image from the plate to the paper. (Offset printing)

Bleaching: Elimination or alteration of the pulp color in order to increase the whiteness.

Brightness: Brightness is measured as the percentage of light in a narrow spectral range reflected from the surface of a sheet of paper. It is not necessarily related to color or whiteness. A paper with a brightness of 98 is an extremely bright sheet with almost all light being reflected back to the viewer. Bright white papers illuminate transparent printing inks, giving cleaner, crisper color, and contrasty blacks.

Broke: Paper and pieces of paper arising at any point in the mill which are suitable only for repulping, e.g. wet paper removed from the paper machine or dry paper such as trim etc., waste paper etc.

Bulk: An expression used principally in the context of papers for book printing to denote the theoretical thickness in mm of 100 sheets of the given paper in 100 g/m². It thus gives an indication of the volume of the paper.

Bulky (Paper ~): Paper which appears to be thick in relation to its substance.

Bursting Strength: A measure of the ability of a sheet to resist rupture when pressure is applied to one of its sides by a specified instrument, under specific conditions. It is largely determined by the tensile strength and extensibility of the paper or paperboard. Testing for bursting strength is very common although its value, except for limited, specific purposes is questionable.

Calender: Device used to compress paper. Constituting a number of fixed superimposed cylinders, one of which can be adjusted in order to change the paper characteristics by altering the level of compression.

Calendering: Smoothing operation between polished cylinders called calenders, this process is usually carried out at the dry end of the paper machine.

Caliper: The thickness of a single sheet of paper measured by a micrometer and expressed in thousandths of an inch.

Carbon Footprint: This is the amount of greenhouse gases emitted during the process of creating a product or service. (See Greenhouses gases)

Cast-Coated: Coated paper, dried under pressure against a polished cylinder to produce a high gloss finish.

Cellulose: The main solid constituent of woody plants, occurring widely elsewhere in the vegetable kingdom. Chemically, it is a linear polysaccharide of high molecular weight. Wood cellulose is the material remaining after a large portion of the lignin and certain carbohydrates have been removed by pulping and bleaching.

Cellulose fibers: Structural filaments which give wood cells its strength.

Chain of custody: A systematic procedure for tracking a material or product from its origin to its final use.

Chalking: The ready removal in the form of a powder, of an insufficiently bound layer of pigment on the paper surface resulting from absorption into the paper caused by over saturation of ink.

Chemical Oxygen Demand – COD: COD determines the amount of organic compounds found in surface water – measured by the mass of oxygen consumed per liter of solution - making it a useful measure of water quality.

Chemical Wood Pulp: Pulp that is prepared from chipped wood by treating with chemicals to remove the non-cellulose material. Used in the better grade of wood pulp papers, and improves the qualities of mechanical pulp when the two are mixed.

Chemical Pulp: Pulp in which wood fibers have been separated by chemical, rather than mechanical means.

Chill Rolls: Cylinders on the web printing press which harden the ink to lower the tem petemperature of the paper after the drying process.

Clothing (machine): Fabrics of various types employed on the paper machine to carry the web and perform other functions. This includes the machine wire and wet and dry felts which can be composed of either natural or synthetic materials.

CMYK: The four primary colors in the printing industry: Cyan (blue), Magenta (red), Yellow and Black.

CO₂: Carbon dioxide is the main greenhouse gas resulting from the combustion of petrol, coal, oil and natural gas.

Coated (paper ~): Paper that has been subject to the process of coating. The coating carried out in the paper machine is generally applied on non-finished paper. The coating process consists of applying a layer of certain substances in order to improve some of the characteristics of the paper: whiteness, opacity, surface, printability.

Coating: Process that consists of applying a mineral pigment (for example kaolin) on one or two sides of the paper. Coating is applied in order to improve printing on the paper.

Collate: The ability of a printer, copier or press to assemble sheets in a proper order, for instance, for binding.

Color: The number of colors depends on the printing units, including the black one for 4-color printing. Direct colors are the result of mixing base inks dedicated to only one printing unit.

Compensation carbon: Action to counterbalance (compensate) greenhouse gas emissions produced by carrying out project aimed at reducing these emissions.

In general, these are projects based on renewable energy, on energy effectiveness and sylviculture.

Conductivity: The electrical property of a sheet of paper which enables it to attract charged toner. Low conductivity can result in poor image quality in digital systems.

Cone: Element of the folding device where the first folding operation is done. This operation is simply called cone folding.

Coniferous trees: Long cellulose fibers conferring on paper good mechanical characteristics.

Converting: Last operation to treat, modify or otherwise manipulate the finished paper to meet the needs of the end-user.

Core: Tube usually made of paperboard on which a paper roll is wound.

Cover Paper: Also called card stock, these papers are heavyweight coated or uncoated paper with good folding characteristics. Their diverse uses include folders, booklet covers, brochures and pamphlets.

Cromalin: Quick proof obtained by photographic means.

Cross direction: The direction in the plane of the sheet, at right angles to the machine direction in a sheet or web of paper EG: Left to Right.

Curl: Natural trend of the paper to wind around its own axis.

C1S: Paper that is coated on one side only.

C2S: Paper that is coated on both sides.

Damping: The process of applying water to the lithographic plate on a printing machine. Also the application of moisture to paper in preparation for a subsequent process, e.g. supercalendering.

Deckle Fill: The width of the paper machine taken up by a making of paper. For economic reasons reel width’s should cover as far as possible the maximum trim width of the machine (Full deckle).

Delignification: The process of removing lignin from wood or other cellulosic material by means of chemicals, leaving a residue of cellulose, hemicelluloses and other carbohydrate materials.

Density: The ability of an object to stop or absorb light. The less the light is reflected, the higher its density, eg a solid black area on film reflects no light and therefore has 100% density.

Die-Cutting: The use of sharp steel rules to cut special shapes from printed sheets.

Digital Imaging Surface: A new and unique surface treatment for both uncoated and coated papers, specifically engineered to enhance paper: toner performace and yield increased print fidelity.

Digital Papers: Papers designed for the speci½c processes of the emerging digital printing technologies. Unlike traditional offset printing, the digital environment is centered in quick turnarounds, short runs, and the ability to vary printed information within the run. Mohawk Digital Papers—Navajo, Options, Super½ne, Satin 2.0, and 50|10plus —are designed for both digital and offset operations, and are available in popular digital sheet sizes and small rolls.

Dimensional Stability: Ability of a paper to retain its dimensions and its shape despite changes in its moisture content due to: Variation in the surrounding atmosphere or variations due to the differing physical and mechanical stresses during printing and converting.

Dioxin: Dioxins are environmentally persistent compounds that find their way into the food chain. They have been linked to chronic diseases such as cancer and are believed to be a cause of birth defects. Dioxins are produced during incineration of wastes and are a contaminant in chemical manufacturing processes. Dioxin is also a by-product of older, chlorine pulp bleaching technologies.

Dry End: Part of the paper machine where the paper passes through steam-heated drying cylinders.

Driers: A series of steam-heated metal cylinders, 30-60 inches in diameter, varying in number up to 130 or more, and arranged in two or more tiers. The cylinders are gear driven, and the wet paper passes over and under successive cylinders. The temperature of the cylinders, their number and their speed determine the drying capacity of the paper machine.

Dummy: A sample of a proposed job made up with the actual materials and cut to correct size to show bulk, style and binding, etc. Also a complete layout of a job showing position of type matter and illustrations, margins, etc.

Duplexing: The ability of a press or printer to print on both sides of a page without having to manually turn the sheet over.

Ecosystem: A system formed by the interaction of a community of organisms with their physical environment.

Elementary Chlorine Free – ECF: The cellulose of paper bleached with oxygen, hydrogen peroxide and dioxide of chlorine instead of elementary chlorine.

Environmental footprint: In an industrial context, it concerns the environmental impact of a company which is given according to the quantity of raw materials and non-renewable resources that it consumes by manufacturing its products, and the quantity of waste and emissions generated during the process.

Environmental sourcing: The purchase of environmentally preferable products, along with efforts to support suppliers with sound environmental practices.

Eutrophication: The process by which a body of water becomes enriched in dissolved nutrients (as phosphates) that stimulate the growth of aquatic plant life, usually resulting in the depletion of dissolved oxygen.

Felt side: Paper side that it is not in contact with the wire of the paper machine.

Felt: Clothing element of the paper machine acting as a blotter in order to eliminate the water.

Finish: Ascertain the appropriateness of the paper's finish to the desired end result. For example, a gloss finish offers the ultimate in reproduction detail, while dull and matte finishes offer easier reading for large quantities of text.

Finishing: It can be the hand operations of lettering and ornamenting the covers of a book or all operations after printing.

Foils: Static bar-like devices situated below the forming wire of a paper machine to help to drain the water from the pulp.

Forest Certification System: Refers to the system whereby forests undergo an external auditing process that focuses on the environmental aspects of commercial forests. This includes the Pan European Forest Certification (PEFC) and the Forest Stewardship Council (FSC) certification.

Format (sheet size): Paper cut up into square or rectangular sheets, taking into account the length and the width.

Formation (of the sheet): The aspect of a sheet of paper when you look-through it. This aspect can be « uniform », « close » or « cloudy ».

Four-Color-Printing: Printing with four different colors; generally black, cyan, magenta, yellow.

Fourdrinier machine: Paper machine type that forms the paper in a continuous sheet; it was named after the Fourdrinier brothers who financed the first operational machine at Frogmore Mill (UK) in 1803.

Free sheet paper: High-quality paper free of groundwood pulp or mechanical wood pulp fibers. Free sheet paper is much more durable and resistant to aging from exposure to air and light than mechanical pulp paper, and is well suited for book paper and catalogs with a long useful life. Its clean white surface is appropriate for the high-quality four-color process printing used in magazines and merchandise catalogs.

FSC - Forest Stewardship Council: International organization which promotes responsible management of the forest has developed principles of forest management which can be used to certify the management of forest companies and a follow-up, checking and labelling system for the wood and the products resulting from wood coming from FSC certified forests. FSC is recognised by Greenpeace and WWF as being the only credible international certification system.

Glazed (paper ~): One side of the paper is made smooth and glossy by drying in contact with a large heated, polished cylinder which forms part of the drying section of the machine. The other side of paper remains relatively rough.

Glossy (paper ~): Coated paper that has been highly compressed.

Grammage: Mass per unit of surface area of paper. It is expressed in grams per square meter (ex: 80 gsm or g/m²).

Gravure paper: Mostly mechanical, highly calendared (smooth) paper with a high ash content, which is produced as coated or uncoated grade. It must ensure uniform ink trapping at high printing speeds.

Greenhouse gas emissions: Emissions in the atmosphere of gases which affect the temperature and climate of the planet’s surface. Certain greenhouse gases are present naturally in the atmosphere, while others result from human activities such as the combustion of fossil energies. They include water vapor, carbon dioxide, methane, nitrous oxide and ozone.

Gripper: A device on a printing machine for holding the sheet during the printing or similar process.

GSM (g/m²): Abbreviation of grams per square meter. A method of indicating the substance of paper on the basis of weight in grams per square meter.

Half-tone dot: The representation of tonal gradation by an image composed of dots of varied sizes, the centres of which are equidistant.

Half-tone screen: A grid in which the lines and spaces are of equal thickness and equidistant used in photographing an original for plate or black making.

Hardwood pulp: Pulp obtained from the wood of hardwood trees by various processes. The fibers are generally shorter and give good opacity to the paper.

Head box: Front end of the paper machine through which the purified and diluted pulp arrives on the manufacturing wire.

Hydrophilic: Readily wetted by water.

Hydrophobic: Water repellent; not readily wetted by water.

Hygroexpansivity: The change in dimension of paper that results from a change in the ambient relative humidity. It is commonly expressed as a percentage and is usually several times higher for the cross direction than for the machine direction. This property is of great importance in applications where the dimensions of paper sheets and cards or construction board are critical.

Hygrometer: Laboratory apparatus which measures air humidity or paper humidity.

Impressions Per Minute/Hour: The number of printed units a press, printer or copier can print in a minute or an hour.

Infeed bar: Element of the web press that allows the crosswise positioning of the paper.

Infeed roller: Element of the printing press that ensures good lengthwise positioning of the paper sheet in the printing units.

Insert: Additional printed material put into a book, newspaper or magazine.

Internal bond: The force with which fibers are bonded to each other within a sheet of paper or paperboard.

Internal sizing: The addition of mineral fillers in order to enhance the opacity and surface resistance of the finished paper.

ISO: The International Organization for Standardization (ISO) is comprised of national standards institutes from 148 countries in partnership with governments and industry to develop international standards. It aims to identify, verify and reduce a business's environmental impact.

ISO 14001: Internationally certified and independent standard, relating to the systems of environmental management used, developed and retained by the International Standardization Organization.

ISO 9001: International Quality Management Standard.

ISO 14001: Internationally certified and independent standard, relating to the systems of environmental management used, developed and retained by the International Standardization Organization.

Jumbo Reel: A parent reel of paper from where smaller reels or sheet sizes are cut.

Kraft paper: German word meaning: strength – high-strength paper made almost entirely of unbleached kraft pulp. Kraft paper is suitable for the production of paper sacks and paper bags. Paper which is produced from wood pulped by a sulphate process which dissolves the lignin that binds the wood fibers together. Kraft has long fibers for added strength and is brown in color.

Kraft pulp: Pulp produced by a process where the active cooking agent is a mixture of sodium hydroxide and sodium sulfide. The term “kraft” is commonly used interchangeably with “sulfate” and is derived from a German word that means “strong.”

Laser printer: A desktop printer that uses a laser beam to create an image on a photoconductive drum. Dry toner is attracted to the charged area and is fused to paper with heat and/or pressure.

Life Cycle: The successive phases in the life of a product, from the extraction and treatment of raw materials to final disposal.

LCA – Life Cycle Assessment: Life Cycle Assessment is an efficient and systematic method by which to evaluate the environmental impact of a product, service or process. The fundamental aim is to lessen the burden on resources and the environment throughout the product's life-cycle, from the extraction of raw materials to disposal (landfill, incineration, recycling, etc.).

Leafy trees: Short cellulose fibers bringing opacity to paper.

Letterpress printing: A printing method, as in the offset lithographic method, but from a relief plate and without the use of damping solution.

Lignin: Organic substance in wood which binds its fibers together and reinforces its structure. Lignin is removed in the manufacture of chemical pulp. Pulp brightness depends on the amount of lignin remaining in the pulp. Paper containing high content will “yellow” in sunlight.

Lithographic Printing: A printing process in which the non-image areas of the printing plate are made hydrophillic and the image areas hydrophobic. This printing process is the ancestor of Offset printing (Printing).

Machine direction: The direction the wire mesh on a paper machine is travelling; over 50 % of the fibers position themselves with their lengths parallel to this direction.

Magenta: Having a dark purplish red shade. One of the primary colors in 4-color-printing.

Mailing: Sending advertisements or other sorts of information to a large number of people by post.

Mat (coated paper ~): On-line coated paper without any mechanical treatment: with rough side, the coat increases the rigidity but still allows us to obtain a good level of print gloss.

Mechanical Paper: Any paper containing 10% or more mechanical wood pulp, such as newsprint.

Mechanical Pulp: Pulp consisting of fibers separated entirely by mechanical rather than chemical means.

Mechanical Wood Pulp: Produced by grinding wood mechanically; used for example in newsprint, and combined with larger proportions of chemical wood pulp for other qualities.

Mineral fillers: Materials such as chalk and china clay that are added to paper in order to change its density or improve its surface.

Moisture Content: The amount of moisture found in a sheet of paper. If the moisture content in a sheet is too high or too low, the paper can curl or build up static, which affects the way it runs through a press, printer or copier.

Net Energy Consumption: Net Energy takes the total amount of energy required to make the paper over its life cycle, and subtracts an energy credit for energy that is created by burning paper. If most of the energy used to make the paper is purchased, then the energy credit might make the Net Energy lower than the Purchased Energy.

NO_x: Nitrogen Oxides. These are emissions that occur when fuels that contain nitrogen are burned. In moist air, nitrogen oxides can form nitric acid, which, in turn, is precipitated as «acid rain».

Offset Paper: Uncoated paper designed for use in offset lithography. Important properties include good internal bonding, high surface strength, dimensional stability, lack of curl, and freedom from foreign surface material.

Offset Printing: A method of printing in which the image on the plate is transferred to the final substrate via an intermediate surface (blanket).

On-Demand-Printing: Term for new business developing around short-run color printing. Small quantities of high-quality color printing can be delivered “on demand” wherever and whenever required.

Opacity: An optical characteristic of the paper. The extent to which a paper is capable of obscuring matter printed on the verso or on an underlying page or other surface.

Operator Side (CC): Side of the paper machine where the staff are working and where the control panels are situated.

Optical Brightening Agent: Dyestuff which is capable of converting u/v light into the visible spectrum and improving the brightness of the paper.

Paging, pagination: Number of pages.

Pantone or PMS (Pantone Matching System): International reference system for direct ink color composition, paper colors, etc.

Parchment: A sheet of writing material made from animal skin, nowadays usually used to denote Vegetable Parchment or parchmentised paper. They have a high resistance to the penetration of grease and atmospheric humidity. (see also Vellum Paper)

PCC – Precipitated Calcium Carbonate: Precipitated Calcium Carbonate is generally made from a high-purity calcium carbonate rock called limestone. Calcium carbonates, including PCC, are considered to be non-toxic.

PEFC – Program for the Endorsement of Forest Certification: Independent organization with a non-profit making and non-governmental purpose, founded in 1999, which deals with the promotion of sustainably, managed forests by means of independent third-party certification.

Perforation: Converting operation consisting of making small holes or line of holes. Perforated paper is easy to separate.

Permanent Paper: Paper free from mechanical wood pulp or unbleached fiber, generally neutral/alkaline sized and containing calcium carbonate filer, made to controlled pH value and alkali reserve, intended for the printing of books and similar works for posterity.

PH Value: A number on a logarithmic scale extending from 0.3 to 14.5 which indicates the active acidity or alkalinity of an aqueous liquid.

Picking: Removal of particle from the paper surface during printing when ink tack is greater than surface strength (Impression).

Pigments: Mineral filler products (powder), added to the pulp before it enters the manufacturing grid, they are mainly used to improve the surface of the paper.

Piping: Defects in reels consisting of ridges running around the circumference, due to moisture take-up by the surface layers.

Plate: Printing form – Offset Printing.

Porosity: A structural property of paper measured by the size and distribution of pores.

Press: In a paper machine, a pair of rolls between which the paper web is passed for one of the following reasons: Water removal at the Wet press; Smoothing and leveling of the sheet surface at the Smoothing press ; Application of surface treatments to the sheet at the Size Press.

Process Color: The colors of ink or toner-cyan, magenta, yellow and black-used in four-color offset and digital printing.

Proof: A pre-production print, made for the purpose of checking the accuracy of lay-out, type matter, tone and color reproduction.

Pulp: Chemical pulp is made from a cellulose raw material (usually wood) by treating it (cooking) with chemicals to separate the cellulose fibers and dissolve the lignin, etc. which bind them together; It can be bleached or unbleached. Mechanical pulp is made from wood by purely mechanical means, i.e. grinding or refining of chips: lignin and other impurities are not removed, and further processing (bleaching) is required for a white sheet to be produced. Fiber obtained from wood by either of the above methods is called primary or virgin fiber. Some pulping processes involve both methods and also include heat treatment.

Pulper: A machine designed to break up, defiber and disperse dry pulps, mill process broke, commercial waste papers, or other fibrous materials into slush form preparatory to further processing and conversion into paper or paperboard. It normally consists of a tank or chest with suitable agitation to accomplish the dispersion with a minimum consumption of power. It may also be used for blending various materials with pulp.

Rag (pulp or paper): Pulp generally produced from rag fibers (hemp, flax mainly dedicated to the production of cigarette papers).

Rainforest Alliance: The Rainforest Alliance is a leading international conservation organization whose objective is to protect the environment, wildlife, workers and communities by implementing better business practices for biodiversity conservation and sustainability.

Raw from the machine (paper~): Paper that is not subjected to any mechanical finishing during its production.

Ream: Unit consisting of 500 identical sheets of paper.

Recto: Face of a sheet, first side printed (Impression). Right-hand-page of book.

Recycled (paper ~): Paper of which the fibrous composition contains a majority of recovered or recycled cellulose fibers (RCF).

Recycling: Using materials recovered from the solid waste stream as raw materials in the manufacturing of new products.

Reel Up: The final process in making paper, after passing through the drying cylinders and, if appropriate, the calender rollers, the newly-made paper is wound onto a jumbo reel : this is the reel up stage.

Refiner: A machine, usually equipped with discs or with a cone and plug, intended for the treatment of fibrous materials in an aqueous medium to give them some of the properties needed for the manufacture of pulp or paper with the necessary characteristics.

Register Marks : A set of fine line crosses or other suitable devices added to the original artwork to provide reference points for the subsequent registration of the colors of a set of printed images.

Renewable Energy: Renewable energy is energy that is derived from continuously available sources that do not rely on exhaustible fossil fuels like coal, oil and gas. Examples of renewable energy are wind, solar, hydroelectric, geothermal and ocean tides.

Retention: The amount of filler or other material which remains in the finished paper expressed as a percentage of that added to the furnish before sheet formation.

Runnability: How smoothly paper runs through a paper machine or printing press. Each grade of paper behaves differently on press. A paper's ability to absorb ink uniformly (absorbency), printed ink gloss (holdout), dimensional stability, and surface texture are all important factors to consider when preparing your design. For example, a paper with excellent opacity will present crisp, full-color images without 'showing through' on the back of the sheet, and can provide more flexibility when designing and laying out the printer's form.

SC (supercalendered) Finish: Surface finish on paper which may vary from relatively dull but smooth to highly glazed, produced by passing dampened paper through a supercalender stack. This is broadly similar to a machine calender stack except that it is separate from the paper making machine and some of the rolls are of compressed fiber.

Score: To partially cut with a rule onto heavy paper or board to break the grain and so to enable easier folding. (Also known as crease)

Set-Off: Unwanted transfer of printing ink from a print to a facing surface (Printing).

Sew: To fasten the sections of a book together by passing thread through the centre fold of each section in such a way as to secure it to the slips. In distinction from stitch.

SFI – Sustainable Forestry Initiative: Initiation program for a sustainable forest which promotes responsible management of the forest in North America and responsible purchases at global level.

Sheeter/Sheeting machine: Machine for cutting the paper webs into sheets.

Sheffield: A test used to measure the smoothness of paper by measuring the rate of airflow over the surface of the sheet. The lower the number, the smoother the sheet.

Signature: Group of pages or sheets. Results of folding sheets, signatures are bundled together.

Size: Resin or other sizing material included in the furnish of a paper to bind the fibers and loading together and to provide greater resistance to ink and greater strength in the sheet.

Sizing: This process can either be applied on the surface of the sheet or in the sheet. In the first case starch is applied to the surface to increase its strength and to resist the penetration of oil based inks (this process is carried out at the size press, which is about two-thirds of the way down the dry end); in the second case chemicals are added to the pulp before the sheet is formed.(See also Internal sizing)

Sludge (paper): The fiber and other components of papermaking that are recovered from wastewater treatment processes.

Smoothness: The property of a surface determined by the degree to which it is free of irregularities. In printing, the smoothness of the paper in the printing nip is important and is referred to as printing smoothness. Smoothness improves as the paper is compressed and locally deformed under mechanical pressure.

Softwood: Long fiber cellulose obtained from the wood of coniferous trees providing good mechanical characteristics to the paper.

Softwood Pulp: A pulp made from softwood or coniferous wood species.

Solid Waste: Solid Waste includes sludge and other wastes generated during pulp and paper manufacturing, and used paper disposed of in landfills and incinerators.

Speck: A particle of contrasting appearance in pulp or paper.

Spine: Part of a book where the pages are fastened and the title is usual printed.

Splicer: Element at the beginning of the web press.

Splices: Joint in a web of paper in or approximately in the cross direction made by an adhesive or an adhesive strip.

PM – Suspended particulate matter: Suspended particulate matter is a mixture of solid and liquid particles, both organic and inorganic, in air or water. In the paper-making process, these can include wood particles and smoke.

Spool (Roll): Continuous length of paper or cardboard wound around a core (a tube serving as the axis of the spool).

Stitch: To sew, staple or otherwise fasten together by means of thread or wire the leaves or signatures of a book or pamphlet.

Supercalender: A calender stack used to increase density, smoothness and gloss of paper. It is constructed on the same general principle as the calendar, except that alternate chilled cast-iron and soft rolls are used in the supercalender. The soft rolls are constructed of highly compressed cotton or paper. It is not an integral part of the paper machine, whereas the calendar is.

Suspended matter: Suspended components in waste water, such as fibers and particles, which remain after its water treatment.

Sustainable: Development practices that are inclusive of business, social and environmental goals.

Sustainable development: Development which satisfies present needs without compromising capacity of future generations to meet their needs.

Surfaced (paper ~): Paper having undergone a sizing process in order to improve characteristics of the surface. The Size Press is also called gluing press. The amount of the sizing pigments is less than 8g per sqm per side

Sylvan: Relating to trees and forests.

System of Environmental Management: An environmental management tool implemented by an organisation that, thanks to the principle of continuous improvement allows them to reduce their impact on the environment on an on going basis.

Tabloïd: Newspaper size with rather small pages and many pictures.

Tensile Strength: The maximum tensile force that a test piece of paper will stand before it breaks under the conditions defined in the standard test method.

Transmission side (TT): Transmission side of the paper machine.

Trimmings: Paper left over from web or sheet cutting operations.

Tack: Property governed by viscosity and adhesion which renders a film of printing ink sticky to the touch.

Uncoated Paper: Paper manufactured with no surface coating. There is a wide variety of grades and levels of quality among uncoated papers.

Xerographic printing: Dry printing process, on a special electric copying machine.