Glossary of Paper Terms
Adsorbable Organic Halogens.
A = Active carbon (charcoal) is a method of measuring the amount of organic chlorine compounds (calculated as organically absorbed chlorine) resulting from bleaching.
O = (Organic) Halogens, Fluorine, Chlorine, Bromine and Iodine.
X = Adsorbable
Acid-free papers are manufactured in an alkaline environment, which prevents the internal chemical deterioration of the paper over time. The addition of calcium carbonate as a buffer also makes the paper resistant to the effects of an external acidic environment.
Rough paper finish created by reducing pressure at the wet presses on the paper machine and with little or no calendaring.
Acid-free paper made to resist deterioration for documents that must last and meet special specifications. (See Acid Free).
Bendtsen smoothness is established by measuring the amount of air escaping between an annular ring and the material surface. The rougher the surface, the greater the loss of air thereby producing a higher reading. A smoother print finish with a greater degree of dot sharpness can be achieved on material that has a smooth surface. The lower the figure, the smoother the surface.
One of the many sources of power used by integrated paper mills is gained from the incineration of black liquor. This liquor is essentially liquefied lignin, which has been removed from the cellulose fibre during the cooking stage.
(TCF) Totally Chlorine Free - The pulp is bleached without the use of chlorine chemicals, ie. No chlorine gas or chlorine dioxide, giving zero AOX level.
(ECF) Elemental Chlorine Free - This pulp is bleached without the use of chlorine gas. However, some chlorine dioxide is used, plus other non chlorine based products such as Oxygen. Pulps using this bleaching method contain up to 0.5kgs AOX per tonne of air dried pulp.
An image that is printed to the edges of a page, or the ability of a press or printer to print an image to the edges of a page. A full bleed document is printed on a larger sheet and is trimmed to size, since ink or toner would foul press cylinders or belts if it actually extended off the edges of the paper. Printers typically charge more for bleeds because more paper is required.
Originally a term applied to cotton-content paper used for printing bonds and legal documents, and distinguished by strength, performance, and durability. Used for letterheads and forms, bond paper may now be made from cotton, chemical wood pulp, or a combination of the two. Today, writing, digital, and cut-size papers are often identified with the bond scale.
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 colour and contrasty blacks.
Ink Technology Developed by Canon.
Cyan, magenta, yellow and black are the process colours of toner or ink used in offset and digital printing. The colours overlap and appear to mix visually to reproduce a complete spectrum of colours.
Caliper is a measure of paper thickness under specified conditions expressed in thousandths of an inch. The micrometer is used to measure caliper.
Made with a surface coating, which allows for maximum smoothness and ink holdout in the printing process. Coated papers are available in a range of finishes from dull to matte, and gloss.
China clay and calcium carbonate combined with starch and latex binder.
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.
Characters per second: measure of matrix printer speed.
When folding it is often necessary to pre-crease. Best results are obtained when folds are made parallel to the grain. Always fold into the bead. Creasing on a litho machine or with the Rotary score method will not always give a satisfactory result.
Wire cylinder used in papermaking process to create effects such as laid, as well as watermarks.
Produced in hand-papermaking by drainage under a wooden frame surrounding the hand mould. The rough edges on hand-made and some machine-made papers were originally considered an imperfection. The deckle edge cam back in fashion with the handcraft revival in the last decade of the 19th century.
Instrument used to measure printed ink density to determine consistency throughout a press run.
Papers designed for the specific 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.
Printing in which an image is applied to paper or another substrate directly from a digital file rather than using film and/or plates.
DPI or Resolution
Dots per inch.
Carefully assembled pages of actual paper stock represent exact form of final printed piece. Helps printer and client visualize written specifications.
Two-colour halftone reproduction from black and white original.
When both sides of paper are copied/printed in one pass.
The ink converts from solid to vapor back to solid on polyester impregnated paper or film.
A printing or copying method which uses an electrical charge to create an image on a photoconductive surface. Toner is attracted to the charged area and then transferred and fused to paper.
Finish imparted to a web of paper in an embossing machine. Process is separate from the main papermaking process and involves running a web of paper between a steel embossing roll and a cardboard backing roll.
Most materials will emboss satisfactorily.
This is an overall process usually carried out on the last unit of the litho process. Emulsion sealers are used to enable the printed work to progress to other departments more quickly, thus minimising the problem of spray or ink rub. Always check that the sealer used is compatible with subsequent processes.
Continuous stationery, typically used for computer printouts and invoices. Holes running down both sides allow the use of pin or tractor feeds.
Woven textile, originally wool but now usually synthetic, used to carry the web while moisture is pressed from it. While on the paper machine, the felt acts as a support for the paper web. Felts, if they are rough, can impart a felt finish to the paper.
The topside of the paper web, which comes in contact with the papermaking felt.
Flecked, Flocked and Fibered
Terms commonly used to describe decorative fiber additives to text and cover papers. Coloured cotton and/or rayon fibers are added to the paper stock to create the look of hand-made paper. Other additives include jute fibers, and coloured bits of paper stock. For a listing of Spicers fiber-added papers consult the stock comparator.
Types and locations of fibrous raw materials.
Different types of laminates are available in both Matt and Gloss. Ensure that printing inks are suited to this process. Eg. Low wax and stable pigments.
Additive in the base sheet, generally calcium carbonate, china clay and titanium.
What the paper looks like when held up to the light. Paper is made from fibres; when they are uniformly distributed, solid ink coverage will go down smoothly. Poor formation may lead to print mottle.
Platen which guides single sheets of paper through a printer.
Fluorescent Whitening Agent. (As O.B.A.)
Genuine Felt Finish
A finish applied to paper by means of marking felts while the paper web is still very wet. These felts impart their distinctive textures by gently rearranging the paper fibres. This creates a soft, resilient, textured surface suitable for printing and relief operations.
Giga (10) Joules
The S.I. (System International) unit of work, energy and quantity of heat.
Gloss is the surface reflectance value at a given angle. The greater the value the greater the surface of Gloss.
The direction along which the majority of fibres lie. The alignment is parallel to the movement of paper as it travels through the paper machine.
As the paper web is carried forward on the machine, the majority of fibres orient themselves in the machine direction. When the web of paper is sheeted, the sheets will be grain long (fibres that run parallel to the long side of the sheet) or grain short (they run parallel to the short side). Grain direction should be considered during the design process for best results during printing, folding, and converting. In sheetfed printing, paper is generally printed grain long. Folds are smoother if they go "with the grain".
Basis weight of paper stated in metric terms.
Heat Set Web Offset. A rotary printing process using heat to set the ink. A cylinder transferring the image from the printing plate to blanket to paper at speeds of 30000 or more impressions per hour.
The arrangement of pages on a press sheet so they are in the proper order when folded.
A characteristic of printing and paper related to the capacity to keep ink sitting on its surface rather than absorbing into the sheet. Better ink holdout produces sharper printed images.
A type of printer that sprays droplets of ink onto paper to forma an image. Continuous inkjet printers spray a continuous stream of ink, which is electronically controlled to print an image. Drop-on-demand inkjet printers shoot out single drops of ink as needed.
Local Area Network.
A linear pattern, which is applied by a dandy roll while the paper is still very wet, to mimic the effect of some hand-made papers. The laid dandy roll is comprised of wires that run parallel to the roll's axis (laid lines), and chain lines, which connect the laid lines and run in the grain direction.
Acronym for Light Amplification by Stimulated Emission from Radiation. An intense, focused beam of light used in many imaging systems to produce images through electronic impulses.
Very smooth, low-moisture papers manufactured in cut sizes for laser printers and office duplicating equipment. Low moisture prevents paper curling from high heat in laser printers. Note: If your job is designed to run through a laser printer, you should specify laser-compatible offset inks.
A desktop printer, which 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.
Light Emitting Diode. An alternative page printer technology, which draws the image on a light sensitive drum using LEDs rather than a laser beam.
One of the many textured effects that is produced by embossing a web of paper with a patterned steel roll. Embossing takes place off the machine as a separate operation.
Fuses dry ink from a cassette ribbon on to paper. 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.
Printer technologies which do not strike the page. Advantages include the speed, quality and near silent operation. Main disadvantage is that they cannot print onto multi-part stationery.
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.
Measure of the percentage of light passage through a sheet of paper. The more opaque a paper is, the less show-through there will be from printing on the sheet below. Basis weight, brightness, type of fibres, fillers, coatings and formation all influence opacity. Generally, opacity and brightness are inversely related to each other: the brighter the paper, the less opaque. Other factors that affect opacity are bulk, surface smoothness and shade.
Also called fluorescent dyes, these are used extensively to make very high bright, blue-white papers. They absorb invisible ultraviolet light and convert it to visible light on the blue/violet end of the spectrum.
Optical Brightening Agent used to brighten the paper. Absorbs UV light and re-emits in the visible spectrum giving the appearance of a whiter or bluer sheet.
Printers which will link direct to a Personal Computer and will print whatever you see on the screen.
As a general rule paper/board substances are up to 200g/m - paper, over 200g/m board.
A company that makes web, sheet, and/or cut size paper and sells it through paper merchants and paper stores.
A liaison between the paper manufacturer and the paper buyer who offers a number of lines of papers and can offer advice to buyers on the best sheets to specify for particular jobs. Merchants sell paper and envelopes to printers.
PDF (Portable Document Format)
A file format which allows a file created on one computer platform to be viewed and printed intact by computer users on a number of different platforms. Created by Adobe Systems for Acrobat products.
Page Description Language. (Example: Adobe Postcript)
Bindery method where all pages are trimmed to single sheets. They are clamped together and a cover is wrapped around the spine. The pages are attached to the cover using an adhesive.
Degree of acidity or alkalinity measured on a scale of 0 to 14 with h7 being the neutral point. pH is important in paper permanence but also in proper functioning of fountain solutions in offset printing.
Porosity is the measurement of airflow through the sheet. The higher the figure quoted, the more porous the material.
Paper, paperboard and fibrous wastes from retail sores, office buildings, homes, municipal collection systems, etc., after such material has passed through its end usage as a consumer item including computer forms, tab cards, photocopies, cancelled cheques and general office waste.
A page description language that describes in detail how images and text on a printed page should look. PostScript code is translated by a raster image processor or RIPped-before it can be used by a digital printer or press.
Pages per minute.
Pre-Consumer Waste - Manufacturing waste such as dry paper generated after the papermaking process (butt rolls, rejected unused stock, roll converting shavings, envelope cuttings, bindery trimmings, and other paper waste resulting from converting, printing and trimming operations). Also includes printer overruns and other printed paper, which has not reached the consumer.
The part of a digital press that drives its printing process.
Conventional ink means an ink, which dries by both oxidation and penetration and does not include "Press open", "Duct fresh" or "Overnight" inks. These may be satisfactory depending upon the type of work to be printed and the material used. Always check that the inks used are suitable for subsequent processes.
500 sheets of paper.
An individually wrapped ream of paper.
Papers that contain postconsumer fibre can currently be called recycled. The Federal Executive Order calls for a 20% postconsumer fibre minimum for uncoated papers, and a 10% postconsumer fibre minimum for coated papers.
Paper which meets minimum reclaimed content standards established by federal, state and municipal governments, and the paper industry. Fibre content usually consists of post-consumer and pre-consumer reclaimed fibre plus virgin pulp. Uniform content standards (percentage of virgin and recycled pulp, proportion of post-consumer and pre-consumer recovered fibre) have not, as yet, been established universally.
Rigidity is the force required to bend a strip of paper or board through a known angle.
Resolution (Ink Jet)
Most Ink Jet machines are generally 360, 720 or 1440 DPI (dots per inch).
Also called off set. Transferring or smearing of ink from freshly printed press sheets to another surface. Printers often add a varnish or aqueous coating in line to avoid set off of printed sheets in bindery operations.
The surface quality of a sheet of paper, related to the flatness of the sheet. Smoothness affects ink and toner receptivity. Smoothness is measured by the Sheffield scale. A higher value typically indicates a rougher sheet. For example, coated paper may have a smoothness of 10-30, whereas vellum offset may have a rating from 200-250.
Solid ink blocks melted prior to printing (eg. Tektronix Phaser).
Surface pH is the degree of an acidity/alkalinity of the material's surface. The pH scale ranges from 1 - 14, 1-6.9 being acid, 7.1 - 14 being alkali, and 7 being neutral.
Paper that is processed through a heated pressurized stack of rolls. There are usually twelve, and they compress and polish the paper, imparting a gloss.
Paper that has a starch or chemical additive to make the paper resistant to water and improve ink hold out.
Text & Cover
A class of high-quality uncoated papers in a wide variety of colours and textures. Text is usually made with a matching or coordinating cover.
This process is not recommended if the material will subsequently be Laser printed. However, some companies are successfully UV curing thermographic letterheads to satisfy the laser copying process.
Paper made by beating the paper fibres until they are very short and translucent. Some translucent papers are transparentised using chemical treatments. Originally used for tracing paper, it is specified for flysheets and other decorative purposes in commercial printing. Translucent papers are fairly difficult to work with as they are fragile with low dimensional stability. However, they provide interesting visual contrasts and have been used successfully in a wide variety of applications.
How well a printed ink can accept the next ink printed compared with how well blank paper accepts that ink. The thickness of ink application; the drying time of that ink; the printing ink sequence; and the settings of the press all affect trap.
The process of overlapping two adjoining colours in an image so that holes are not left in the image by the normal registration variations of the printing process. There is usually some debate about who should handle trapping, the designer or the printer - so it's important to discuss the matter before any files are created.
Printing or the ability to print different text and/or images on each sheet of paper that runs through a printer or press. Both the press and the software driving it must be able to offer this capability in order for the process to work.
There are four usual ways of varnishing. Machine which is carried out on the litho machine and puts down a very thin layer of varnish, either overall or in certain areas. UV which can be put down on a litho machine fitted with a UV drier and can either varnish overall or in defined areas. Roller Coat which is an overall process with a UV drier. Silk Screen which is carried out on a silk screen machine with a UV drier. With this system it is possible to varnish defined areas with a very thick varnish layer. Always use inks which are recommended for varnishing. It is best to try to leave narrow channels free from UV varnish in the areas to be creased.
A process on which fountain solution is not necessary. Non-image areas of the printing plate are treated with silicone so that they reject ink.
Designs formed in fine wire or in low-relief metal castings and sewn onto the dandy roll. The resulting thick and thin areas make the watermark slightly more translucent than the rest of the sheet.
A printing press or printer that is fed with a continuous reel of paper.
The side that is in contact with the wire on the paper machine, as distinguished from the felt or top side.
Whiteness related to the entire visible spectrum. The CIE whiteness formula gives the best correlation between instrumental and visual assessment of whiteness.
Description used of pulp and paper meaning that they contain little or no mechanically ground fibres. Implies that fibres are chemically treated, thereby eliminating lignin and making the product purer, whiter and stronger. Woodfree is an historical paper-making term shortened from "groundwood-free". However, when used in connection with finished paper products now widely available from office super stores etc, it understandably causes confusion amongst end consumers who wrongly assume it to mean the product thus described is literally woodfree, ie. Does not involve trees.
Most common plain surface paper used today. The opposite of Laid, it refers to the wire pattern created by a "wove" dandy roll without chain lines.
Glossary of Environmental Terms
Adsorbable Organic Halogens. Collective term for the halogen compounds (chlorine, fluorine, bromine and iodine) bound to organic substances, for example in waste water from the mill. The compounds arise when bleaching with chlorine-containing chemicals although they can also occur naturally and are potentially detrimental to water quality. The lower the AOX level the better.
Fuels from renewable raw materials such as bark, black liquor, logging residues and effluent sludge.
A German environmental label, which covers many products, including paper. It takes a ‘cradle to grave’ approach, considering manufacture and disposal as well as product use.
Chain of Custody
The means of tracking a product along the supply chain. For instance, being able to trace paper from the forest of origin, through pulp and paper mill, paper merchant and printer to the end user. Often a third party audits the Chain of Custody system, as with the FSC and PEFC schemes.
Combined Heat and Power. A power-generating unit that provides heat and electricity on site rather than drawing energy from the grid. CHP units can have the benefit of proportionally lower emissions to air than power stations. Many paper mills use CHP.
Corporate Social Responsibility. The continuing commitment by business to behave ethically and contribute to economic development while improving the quality of life of the workforce and their families as well as of the local community and society at large including the environment.
Dioxins are organochlorines, unwanted and toxic by-products formed in paper making when chlorine from bleaching combines with molecules in wood. They are also formed during the manufacture
of PVC. Dioxins have been linked with hormone disruption and an increased risk of cancer. Both the paper and plastics industries have made major reductions to the release of dioxins in recent years.
De-Inked Pulp. Pulp consisting of fibre from paper previously printed, which has had the ink removed.
Elemental Chlorine Free. Paper pulp bleached without the use of elemental chlorine but instead using some chlorine dioxide, along with non-chlorine agents such as oxygen. Pulps using ECF methods
contains up to 0.5kg of AOX per tonne of air-dried pulp.
Eco-Management and Audit Scheme. The European Union’s regulated environmental management system. Similar to ISO 14001 but also requires public reporting.
Environmental Management System. A business process that ensures that environmental matters are addressed through a documented system.
Fuels such as coal, gas, oil, peat, biofuels (such as bark) or electricity generated by a combined heat and power unit or bought in from the grid. The source of energy can influence the air emissions i.e. coal produces higher emissions than gas.
European Union scheme to promote ‘green’ products, including paper. It uses a stringent life cycle analysis to identify where a product might harm the environment (manufacture, distribution, disposal etc.) taking into account various factors such as energy usage and emissions. Rarely used for paper products.
Eugropa Recycled Mark
Similar to the NAPM scheme but only requires 50% of fibre to be recycled. For use Europe-wide but now defunct.
Finnish Forest Certification System. A scheme for auditing forestry operations in Finland, taking into account the effects on the environment. Now part of the PEFC scheme.
Forest Stewardship Council. An international organisation promoting responsible forest management. FSC has developed principles for forest management which may be used for certifying the management of forest holdings, and a system of tracing, verifying and labelling timber and wood products which originate from FSC-certified forests.
Integrated Pollution Prevention and Control. IPPC seeks to prevent or minimise air, water and soil pollution by emissions from industrial installations in the community.
The standard published by the international Standards Organisation specifying the requirements of an environmental management system.
Life Cycle Assessment / Analysis (LCA)
A method of evaluating the environmental impact of a product ‘from cradle to grave’, including how it’s made, how it’s used and how it’s disposed of.
Offcuts and rejected material that has not left the paper mill. Broke is routinely re-pulped and the fibre used in the production of new paper. Mill broke is not normally considered to be true recycled fibre.
NAPM Agriwaste Mark
The National Association of Paper Merchants (UK) scheme for recognising paper that contains at least 75% non-wood waste material, such as hemp, straw, cotton, bagasse or linen.
NAPM Recycled Mark
The National Association of Paper Merchants (UK) scheme for designating a paper as recycled.
Non-Governmental Organisation. Term applied to organisations such as charities and pressure groups. Environmental NGOs (sometimes referred to as ENGOs) include Friends of the Earth (FoE), the
Worldwide Fund for Nature (WWF) and Greenpeace.
An environmental label encouraging production methods that create minimum environmental impact. Evaluation for paper is based upon strict limits for emissions and effluent from pulp and paper mills.
Old Growth Forest (OGF)
Term sometimes applied to old, relatively untouched forest rich in biodiversity. May also be called High Conservation Value Forest (HCVF), pristine or natural forest.
‘Product declarations’ produced by some paper manufacturers, which list environmental information for their grades.
Programme for the Endorsement of Forest Certification. A scheme for auditing forestry operations, taking into account the effects on the environment.
These are a group of chemicals added to plastics (such as PVC) as a plasticiser in order to make flexible grades. Phthalates are alleged to be hormone disrupters although this has not been conclusively proven.
Waste that has reached the end user, typically homes and offices.
Waste that has left the mill but has not reached the end user. Typically trimmings and rejected material from printers, envelope converters etc.
Recycled Fibre Classification
Mill Broke – Waste that has not left the mill.
Pre-consumer fibre – Waste that has left the mill but not reached the consumer, typically from the printer or converter.
Post-consumer fibre – Post-consumer waste, collected from homes, offices etc.
Post-consumer mechanical fibre – Post-consumer waste, typically newspapers.
To be classified as recycled the grade should contain no less than 50% of the total fibre from any combination of the above sources with the percentages given for each.
Sustainable Forestry Initiative. The American Forest and Paper Association’s Sustainable Forestry Initiative aims to ensure ongoing renewable resources across the country.
A way of living and working which meets the needs of the present without compromising the ability of future generations to meet their own needs.
To obtain the Recycled label, a paper must contain recovered materials. The amount may vary considerably, from small percentages of pre-consumer to 100% post-consumer materials, and any combination of the two. Most recycled papers will have a recovered content of at least 20%.
Totally Chlorine Free. Paper pulp that is bleached without using chlorine in any form, thus giving an AOX level of zero. The alternative bleaching agents used might be liquid oxygen, hydrogen peroxide or
Woodfree is a description of pulp and paper meaning that they contain little or no mechanically ground fibres. Implies that fibres are chemically treated, thereby eliminating lignin (the substance that binds wood fibres together in the tree) and making the product purer, whiter and stronger. Woodfree is an historical paper-making term shortened from ‘ground wood-free’ and does not denote a paper or pulp made from materials other than wood.
WWF Forest and Trade Network (formerly 95+ group)
A voluntary collection of companies committed to the improvement of forest management standards. The group is administered by the World Wide Fund for Nature.