Paper Dictionary
Paper Dictionary
Absolute Humidity
The actual weight of water vapor contained in a unit weight of air, expressed in grams per cubic meter in
metric system and pounds per cubic feet in English system.
Absolute Viscosity
A characteristic of one-component liquids which have a constant ratio of shear stress over shear rate
(constant viscosity)
Absolute White
In theory a material that perfectly reflects all light energy at every visible wavelength; in practice a solid
white with known spectral data that is used as the "reference white" for all measurements of absolute
reflectance. (When calibrating a spectrophotometer, often a white ceramic plaque is measured and used
as the absolute white reference).
Absorbency
The extent to which a paper will take up and hold a liquid.
Absorbent Core
The principal fluid-holding component of disposable hygiene products. Absorbent cores usually contain a
combination of absorbent cellulose fibers (fluff pulps) and super-absorbent polymers composed of
polyacrylates. Advanced cores can contain very specialized absorbent cellulose fibers, synthetic fibers
and super-absorbent polymers as well as fluff pulps.
Absorbent Paper
Papers having the specific characteristic of absorbing liquids such as water and ink. These papers are
soft, loosely felted, unsized and bulky e.g. blotting paper.
Accept
Accepted portion of pulp after cleaning and or screening operation.
Acetate Fiber
A manufactured fiber in which the fiber-forming substance is cellulose acetate (US Federal Trade
Commission (FTC) definition). Acetate fibers are derived by treating pure cellulose, which has been
extracted from vegetable matter and generally wood pulp or cotton linters, with acetic anhydride. The
resulting product is dissolved in acetone and extruded into filaments and the acetone evaporated. Acetate
fibers are moderately strong, generally soft and lustrous like rayon. Acetate staple and filament fibers are
more commonly used in weaving operations supplying end-markets such as lingerie, blouses, dresses,
men’s ties and other apparel. (Source: http://www.inda.org/wp-content/uploads/2015/04/glossaryfc.pdf
)
Acetate Pulp
A highly purified (high alpha cellulose) pulp made especially to be dissolved in acetic acid, acetic
anhydride and sulfuric acid to make acetate rayon and acetate fiber.
Accelerated Aging
Exposing paper at elevated temperature usually at 110C in an oven or on a hot plate. The purpose of
accelerated aging is to simulate the effect of aging in the laboratory.
Accordion Fold
A term for two or more parallel folds that result in the sheet opening like a fan. Accordion folds are used
on products such as brochures and maps.
Achromatic
Material that is white, gray and black and have no color or hue.
Acid Alum
A mixture of aluminum sulfate (papermaker's alum) and sulfuric acid.
Acid Detergent Fiber (ADF)
Organic matter that is not solubilized after 1 hour of refluxing in an acid detergent of
cetyltrimethylammonium bromide in 1N (Normal) sulfuric acid. ADF includes cellulose and lignin.
Acid Free Paper
A type of paper, which does not contain any acidic substance that may affect acid sensitive material. Acid
free paper is anti rust and is used for metal wrapping.
Acid Hydrolysis
The treatment of cellulosic, starch, or hemicellulosic materials using acid solutions (usually mineral
acids) to break down the polysaccharides to simple sugars..
Acid Migration
The transfer of acid from an acidic material to a less acidic or neutral-pH material. Occurs when neutral
materials are exposed to atmospheric pollutants or when two paper materials come in contact. Acid can
also migrate from adhesives, boards, endpapers, protective tissues, paper covers, acidic art supplies, and
memorabilia.
Acid Proof Paper
A paper that is not affected by acid physically or chemically. This paper is used with substance containing
acid.
Acid Sizing
Internal sizing carried out in acidic pH range (0-7). Rosin and alum sizing is acid sizing.
Activated Carbon
A highly absorbent powdered or granular carbon used for purification by adsorption.
Activated Sludge
The biomass produced by rapid oxygenation of effluent.
Active Alkali (AA)
Caustic (NaOH) and Sodium sulfide (Na2S) expressed as Na2O in alkaline pulping liquor.
Additives
Clay, fillers, dyes, sizing and other chemicals added to pulp to give the paper greater smoothness, color,
fibered appearance or other desirable attributes.
Adsorbable Organic Halogen (AOX)
A measure of the amount of chlorine that is chemically bound to the soluble organic matter in the
effluent.
Aerated Lagoon
A biological wastewater treatment method in which air (oxygen) fed into an aeration basin reduces the
effluent load.
Air Blade
A stream of air pressure across the width of roll to remove excess liquid/coating solution.
Air Brush Coater
A coater, which uses the pressurized air to atomize the coating mixture and spray it on the paper.
Air Dry (AD)
Refers to the weight of dry pulp/paper in equilibrium with the atmosphere. Though the amount of
moisture in dry pulp/paper will depend on the atmospheric condition of humidity and temperature but as a
convention 10% moisture is assumed in air dry pulp/paper.
Air Drying
Using hot air to dry pulp or paper sheets.
Air Filter Paper
A type of paper used for filtration of air to remove suspended particles. (car air filter, vacuum bag etc.)
Air Knife Coater
A device that applies an excess coating to the paper and then removes the surplus by impinging a flat jet
of air upon the fluid coating, leaving a smooth, metered film on the paper.
Air Laying or Air Laid Process
A nonwoven web forming process that disperses fibers into a fast moving air stream and condenses
them onto a moving screen by means of pressure or vacuum.
Air Laid Nonwoven
An air laid web that has been bonded by one or more techniques to provide fabric integrity.
Air Laid Web
A web of fiber produced by the air laid process.
Air Laid Pulp
An air laid nonwoven that is produced with fluff, wood pulp. The web can be bonded with resin and/or
thermal plastic resins dispersed within the pulp.
Air Mail Paper
It is lightweight, high opacity, good quality writing/printing type paper used for letters, flyers and other
printed matter to be transported by airlines.
Air Permeability
Commonly referred to as "porosity." The ease with which pressurized air can flow through a paper's
thickness. Typically measure by the Gurley or the Sheffield porosity tests, which measure the volumetric
flow of air through the paper thickness.
Air Pollution
The contamination of air around the plant due to the emission of gases, vapors and particulate material in
the atmosphere.
Albumin Paper
A coated paper used in photography; the coating is made of albumen (egg whites) and ammonium
chloride.
Algae
Micro organic plant life that forms in paper mill water supplies.
Algicides
Chemicals added in to the paper mill water (fresh, white, back etc.) system to reduce or prevent growth of
algae.
Alkali Lignin
Lignin obtained by acidification of an alkaline extract of wood.
Alkfide Process
A variation of the kraft process using hydrosulfide (sulfide-type cooking chemical). It was developed for
continuous cooking using a two-body digester for a two-stage cook.
Alkali Resistance
Freedom of paper from a tendency to become stained or discolored or to undergo a color change when
brought in contact with alkaline products such as soap and adhesives.
Alkaline Extraction
Alkaline extraction, i.e. E stage, is used in lignin removal before or between bleaching stages; the stage is
often enhanced with an oxidizing agent, oxygen (Eo stage), hydrogen peroxide (Ep stage) or both (Eop
stage).
Alkaline Papermaking
Paper manufactured under alkaline conditions, using additives, basic fillers like calcium carbonate and
neutral size. The anti-aging properties in alkaline paper make it a logical choice for documents where
permanence is essential.
Alkaline Pulping
Pulping by alkaline solutions of sodium hydroxide, with or without sodium sulfide. Without sodium sulfide
it is called soda process and with sodium sulfide it is known as Kraft or sulfate process.
Alkenyl Succinic Anhydride (ASA)
ASA is a sizing agent designed to increase resistance to water penetration in the case of paper formed
under neutral or alkaline conditions. ASA is especially used in cases where full cure is desired before the
size press and where it is important to maintain a high frictional coefficient in the paper product. ASA can
improve paper machine runnability and preserve paper's dimensional stability by limiting penetration of
size-press solution into the sheet.
Alpha Cellulose
The portion of the pulp or other cellulosic material that will not dissolve in 17.5% NaOH (Sodium
Hydroxide) solution at 20oC.
Alpha Pulp
A specially processed, high alpha cellulose content, chemical pulp. It is also called dissolving pulp.
Alternative Fibers
Common name for non-wood or tree free fibers.
Alum
The paper maker alum is hydrated Aluminum Sulfate {Al2(SO4)3}. It is used to adjust the pH of the mill
water or as a sizing chemical in combination with rosin size.
Aluminium Foil Lamination
The combination of thin Aluminium foil with a paper backing used as a positive moisture barrier. Normal
combination is kraft backing with Aluminum foil laminated to the kraft by means of asphalt, adhesive, or
polyethylene. The Aluminum foil can also be coated with polyethylene.
Annual Vegetable Fiber or Agricultural Residue Fiber
A source of fiber for pulp and papermaking, including, for example, wheat or rice straw or other fibrous by-
products of agriculture.
Anaerobic Reactor System
An effluent treatment system that uses microbes in the absence of oxygen to break down effluent
constituents into methane, carbon dioxide and hydrogen sulfide.
Animal Fiber
Papermaking fibers such as wool obtained from animals.
Annual Crop Fibers
Papermaking fibers derived from plant harvested on a seasonal basis such as wheat straw, rice straw etc.
Annual Ring
Papermaking fibers derived from plant harvested on a seasonal basis such as wheat straw, rice straw etc.
Anthra Quinone (AQ)
A quinoid compound added to white liquor (alkaline cooking liquor) to improve pulp yield and to increase
the rate of delignification.
Anti-foam or Defoamer
Chemical additives used at wet end to reduce or eliminate tendencies of the machine white water to
foam. For more details
Anti-Oxidant Board
Boxboard chemically treated to increase the shelf life of foods containing fats and oils by retarding
rancidity of such products when packaged in cartons made of it. The treatment does not change the
appearance of the board and is non-toxic and odorless.
Antiquarian
The largest available handmade paper (53 x 31 inches or 134.6x78.7 cm).
Anti Rust Paper
Paper containing added substances which give it the property of protecting the surfaces of ferrous metals
against rusting.
Antique Finish
A term describing the surface, usually on book and cover papers, that have a natural rough finish.
Applicator
Means of applying the aqueous coating, sizing or coloring to the paper web.
Apparent Density
Weight (mass) per unit volume of a sheet of paper obtained by dividing the basis weight by the Caliper
(thickness).
Apparent Viscosity
A characteristic of multi-component liquids that have a variable ratio of shear stress over shear rate
(variable viscosity depending on conditions).
Approach Flow System
The stock flow system from Fan pump to headbox slice. The term approach flow system refers
specifically to the fan pump loop where in the pulp mixture is measured, diluted, mixed with necessary
additives, and finally screened and cleaned before being discharged on to paper machine wire.
Aqueous Coating
A water-based coating applied after printing, either while the paper is still on press ("in line"), or after it's
off press. An aqueous coating usually gives a gloss, dull, or matte finish and helps prevent the underlying
ink from rubbing off. Unlike a UV coating or a varnish, an aqueous coating will accept ink-jet printing,
making it a natural choice for jobs that require printing addresses for mass mailings.
Aragonite
A crystalline form of precipitated calcium carbonate that tends to adopt a needle-like shape, often used in
coatings.
Archival Paper
A paper that is made to last for long time and used for long lasting records.
Art Paper
High quality and rather heavy two-side coated printing paper with smooth surface. The reproduction of
fine screen single- and multicolor pictures ("art on paper") requires a paper that has an even, well closed
surface and a uniform ink absorption.
Artificial Parchment
Wood free paper that is produced by fine and extended grinding of certain chemical pulps and/or the
admixture of special additives. As a result of the "smeary" grinding, the fiber structure closes
homogeneously. It is used e.g. for wrapping meat and sausages or as corrugating medium for biscuit
packaging.
Ash Content
The residue left after complete combustion of paper at high temperature. It is generally expressed as
percent of original test sample and represents filler content in the paper.
Aseptic Packaging
Extends the shelf life of non-refrigerated beverages and foods. Laminates and extruded coatings applied
by the customer ensure an appropriate liquid barrier. Aseptic grade board is clay-coated on one side and
is suitable for gravure, offset, and flexographic printing.
Asphalt Laminated Paper
Two sheets of natural kraft paper laminated in a single ply by means of asphalt. This is used as a
moisture barrier; also to resist action of weak acids and alkalis.
Automatic Packaging System
Term applicable to any one of several available systems for open mouth and valve bag packaging where
bags are automatically applied to filler spout, filled, weighed, closed (if open mouth), palletized, and shrink
wrapped.
Azure
The light blue color used in the nomenclature of "laid" and "wove" papers.
B
Rs.1,275 Rs.1,400 Rs.1,250
Baby Dryer
A small diameter drying cylinder located in the dry end section of a paper machine.
Back End
That portion of a paper machine following the dryer section where the winders, rewinding reels, slitters,
and calenders are located.
Back Liner
The back side layer in a multi-ply paperboard. Normally back liner is made out of inferior grade pulp
compared to top liner.
The surface of the boxboard which forms the interior of the carton.
Backbone
The back of a bound book; also called the spine.
Backing Roll
Rubber covered roll against which the metering device such as rod or blade can press.
Backing up
Printing the reverse or back side of a sheet that has already been printed on one side.
Back Water
See White Water.
Baffle
A device which obstructs the flow of fluid, whether to aid mixing or restrict the flow rate.
Bag House
An air pollution control device that captures particulate in filter bags.
Bag Paper
Any paper made to be used in the manufacturing of bags.
Bagasse
Sugarcane residue left after extracting the juice.
Baggy Roll
Mill roll defect usually associated with a variation in caliper and/or basis weight across the width. Rolls
are normally checked for baggy areas by striking with a baton and listening for variations in audible pitch.
Bale
A large rectangular shaped compressed package of waste paper, rag, pulp etc. Bale dimensions and
weight varies widely depending on the baling material and handling capabilities.
Bale Pulper
A pulper designed to handle and pulp entire bale of paper.
Baling
Compressing and wrapping a material with wire, twine, string to form a unit which is more readily handled,
stored and transported.
Bamboo
A plant of grass family grown in Asian countries and used for papermaking fibers.
Banknote or Currency Paper
Used for printing currency. De-facto highest grade of paper. Very high folding endurance, permanency,
tensile strength, suitable for 4-colour printing, with watermark and other falsification safeguards such as
embedded metal strip. Often contains cotton fibers.
Bark
The outer protective layer of a tree outside the cambium comprising the inner bark and the outer bark.
The inner bark is a layer of living bark that separates the outer bark from the cambium and in a living tree
is generally soft and moist. The outer bark is a layer of dead bark that forms the exterior surface of the
tree stem. The outer bark is frequently dry and corky
Barker or Debarker
An equipment used to remove bark from wood.
Barking or de-barking
Removing bark from wood.
Barograph Paper
Red thin paper coated on one side with a white wax, so that the needle of the barograph make a red line
on a white ground, sold in rolls and coils and to suit the type of barograph.
Base Paper or Base Stock
Refers to paper that will be subsequently be treated, coated or laminated in other ways.
Basic Dye
Dye that have a positive charge due to amine groups and
have a strong affinity for the surfaces of high-yield fibers. Basic dyes are economical, have high color
strength but very poor lightfastness.
Basis Weight
In English system of units, basis weight is the weight in pounds of a ream (500 sheets) of paper cut to a
basic size. (Basic size differs from category to category of the paper. Basic size for Bond and Ledger is
20"x26", book, offset and text paper have basic size of 25"x38"). In metric system of units, basis weight is
the weight in grams of a single sheet of area one square meter. Basis weight is also called as substance
and grammage in metric system of units.
Bast Fibers
Fibers derived from the bark of some annual plants such as flax, gampi, hemp, jute, kozo and mitsumata
etc. Main characteristic of these fiber is long length.
Bastard Size
The non-standard sheet size of a given grade.
Batch Cooking
A chemical
Batt
A collection of fibers assembled into a sheet suitable for needle punching. The term is synonymous with
web.
Beater
An equipment used for beating, refining and mixing pulps.
Beater Dye
Dye added to the beater to color the pulp.
Beater Loading
Addition of a filler to the pulp in the beater.
Beating or Refining
The mechanical treatment of the fibers in water to increase surface area, flexibility and promote bonding
when dried. One of the unintended effect of beating is fiber length reduction.
Effect of Degree of Beating on Paper Properties
Properties Increased Beating Decreased Beating
Belt Washer
Washer, which uses rotating wire for dewatering and washing of pulp.
Bending Resistance/Flexural Stiffness
Corrugated board's ability to resist bending, along with its edge crush resistance, relates to the top-to-
bottom compression strength and general performance of corrugated containers.
Bible Paper
Thin white opaque heavily loaded, used for printing bibles. Not suitable for pen and ink, because of its
absorbency.
Binder
Chemicals which facilitate fiber bonding.
Binder (Coating)
A natural or synthetic compound used to adhere coating to the paper surface.
Biocide
A biological control chemical such as fungicide or a bactericide used in papermaking.
Biodegradable
Capable of destruction/decomposition by biological action.
Biochemical Oxygen Demand (BOD)
When effluent containing biodegradable organic matter is released into a receiving water, the
biodegradation of the organic matter consumes dissolved oxygen from the water. The BOD of an effluent
is an estimate of the amount of oxygen that will be consumed in 5 days following its release into a
receiving water; assuming a temperature of 200C.
Biological Waste Water Treatment
A method of cleaning up waste water using living micro-organisms such as bacteria
Biomass
Any plant-derived organic matter. Biomass available for energy on a sustainable basis includes
herbaceous and woody energy crops, agricultural food and feed crops, agricultural crop wastes and
residues, wood wastes and residues, aquatic plants, and other waste materials including some municipal
wastes. Biomass is a very heterogeneous and chemically complex renewable resource..
Biomass Boiler or Hogged Fuel Boiler
Biomass boilers burn bark, saw mill dust, primary clarifier sediment and other solid waste, and other
wood-related scrap not usable in product production. Also called "hogged fuel" boilers, biomass boilers
make steam and heat for mill use.
Bio-sludge
Sludge formed (in the aeration basin) during biological waste water treatment or other biological
treatment process.
Bitokoshi
Bitoko/Bitokoshi is a grade of printing and writing paper unique to Japan. It is a very lightly coated paper,
occupying a niche market between LWC and coated woodfree papers. The furnish includes both chemical
and mechanical pulp in variable proportions, thus the Japan Paper Association (JPA) recognises both
woodfree bitokoshi and mechanical bitokoshi depending on the proportion of mechanical pulp in the
furnish.
Black Liquor
The liquor that exits the digester with the cooked chips at the end of the Kraft cook is called "black" liquor.
Blackening
Defect associated with calendered paper occurring as unintended local areas of apparently darker or
grayer color due, for example, to the paper being too damp when passed through the calender.
Blank or Black Box
A flat sheet of corrugated or solid fiberboard that has been cut, slotted and scored so that, when folded
along the score lines and joined, it will take the form of a box.
Blade Coater
A device that first applies a surplus coating to paper and then remove extra color after evenly leveling by
means of a flexible steel blade.
Blank
Category of paperboard ranging in thickness from 15 to 48 points (Graphic art terminology).
Bleach Plant
Section of a pulp mill where pulp is bleached.
Bleaching
A chemical process used to whiten and purify the pulp. Bleaching also adds to the sheet's strength and
durability.
Bleaching Sequences
Series of subsequent bleaching stages, typically described by abbreviation such as CEHH (Chlorination,
Extraction Hypochlorite, Hypochlorite .
Bleed
The feathered edge of inks caused by absorption into un-sized paper.
Bleed (corrugation)
The penetration of laminating agents, such as asphalt, through the kraft plies making up the combination.
Bleed Fastness
The ability of a dye to remain attached to fibers in paper even when exposed to fluids or to sweaty hands.
Bleed Through
When printing on one side of a sheet of paper shows through to the other side.
Blending or Mixing
Blending of different pulps in a chest to achieve quality of the final product.
Blind Drilled Roll
A matrix of small holes drilled into the soft press roll which aid the water removal capability of that roll.
Blind Embossing
A printing technique in which a bas-relief design is pushed forward without foil or ink.
Blind Image
Image debossed, embossed or stamped, but not printed with ink or foil..
Blister
Defect on a paper surface often shaped like a human blister. It is due to de-lamination of a limited portion
of paper without breaking either surface.
Blister Pack
This term describes a packaging system that is a combination of board and plastics. The board, usually
made from lower grades of waste paper, can be lined in whole or in part on one or both sides, to carry a
printed message or advertising. The product is sealed to the board by a transparent plastic film. This
system is often used for small products with difficult shapes and sizes.
Blister Resistance
Resistance of paper to developing blister during printing and print drying.
Blotting Paper
An un-sized paper used generally to absorb excess ink from freshly written manuscripts, letters and
signatures.
Blow
It is the discharging of the pressure and contents of the digester in to blow tank.
Blow Heat Recovery System
The system used to recover heat from the flash steam generated while digester is blown in to blow tank.
Blow Tank
The tank in which cooked chips and spent liquor is blown from digester at the end of the cooking cycle.
Blue Angel
It is label defined by the German Federal Environmental Agency. The Blue Angel label is awarded to
papers which do little damage to the environment. The paper is controlled in detail: its composition, its
production process and its conversion. Only papers made from 100 % post consumer waste paper are
certified..
Board
Thick and stiff paper, often consisting of several plies, widely used for packaging or box making
purposes. Its grammage normally is higher than 150 g/m2 or thickness is more than 9 point (thousandth
of an inch).
Bogus
Paper of inferior quality to a standard grade.
Boil Out
The occasional cleaning of a paper machine system, during a shut-down, by filling the system with a hot
solution the usually contains detergent and either NaOH, an acid, or an enzyme.
Bond Paper
The name "bond" was originally given to a paper, which was used for printing bonds and stock
certificates. It is now used in referring to paper used for letterheads and many printing purposes.
Important characteristics are finish, strength, freedom from fuzz, and rigidity.
Bonded Airlaid
A thermal bonding process in which airlaid fibers are cured in a large oven and passed through heated
rollers to create an overall or a patterned bond.
Bonding Strength
The internal strength of a paper; the ability of the fibers within a paper to hold to one another. Bonding
strength measures the ability of the paper to hold together on the printing press or other converting
processing machines. Good bonding strength prevents fibers from coming loose ("picking"). Bonding
strength of fiber is improved by beating/refining and/or adding bonding agent.
Bone Dry
Moisture free or zero moisture.
Book Paper
A general term used to define a class or group of papers having in common physical characteristics and
properties that make them suitable for printing and other uses i graphic art industry.
Bow Roll
Bow Rolls are also known as Banana Rolls, Spreader Rolls, Curve rubber expander. Bow rolls are useful
for removing of wrinkles, slack edges, spreading and slit separation. Most of the Expander Rolls are driven
by web tension itself without any extra drive. Bowed Rolls are key component to making wrinkle free
paper as well as keeping clothing in top working condition on some Paper Machines.
Box
A rigid container having closed faces and completely enclosing its contents.
Boxboard
A class of board frequently lined on one or both sides, with good folding properties and used for making
box and cartons.
Breaking Length
The length beyond which a strip of paper of uniform width would break under its own weight if suspended
from one end. Usually expressed in meters.
Breaks
Rupture of paper on the paper machine during paper making. It the paper on couch roll, it is termed couch
break. If the paper breaks in paper section, it is termed as press break. If the paper breaks in dryer section,
it is dryer breaks and so on.
Breast Roll
A medium size metal or plastic/fiberglass/granite covered roll located at the headbox side of the paper
machine to support the wire.
Broke
Paper that is unusable because of damage or non-conformity to the specifications. It is put back in to the
pulping system.
Broke Pit
A pit below the machine in to which broke is disposed from the machine floor.
Broke Pulper
A broke pulper is used to break down the broke into a stock that can be pumped and treated. This term
can cover a wide range of machines and is often used to refer to both stand alone broke pulpers and
under the
machine (or UTM) pulpers which receive paper directly from the machine including any trim. A stand
alone broke pulper is used to process finished reels that have been rejected or for broke that for any
reason has been baled or collected away from the UTM pulpers.
Brown Pulp
A mechanical pulp made from wood, which is steamed before grinding. The color-bearing, non-cellulosic
components of the wood remain with the pulp. The pulp is generally used for wrapping and bag paper.
Brown Stock
The unbleached chemical pulp.
Brush Coating
A Coating method in which the freshly applied coating color is regulated and smoothed by means of
brushes, some stationary and some oscillating, before drying.
Brush Finish
A paper that is run under stiff brushes, after coating, to give a high finish.
Buffering
The neutralizing of acids in paper by adding an alkaline substance (usually calcium carbonate or
magnesium carbonate) into the paper pulp. The buffer acts as a protection from the acid in the paper or
from pollution in the environment.
Bulk
Reverse of density, expressed as cubic centimeter per gram.
Burnout
The loss of color during drying.
Burnt Paper
Paper, which has been discolored and is brittle, but otherwise intact.
Burst
An irregular separation or rupture through the paper or package.
Air Shear burst: Burst caused by air trapped in the winding roll producing rupture of the web along the
machine direction.
Caliper shear burst. Cross Machine tension burst that generally occurs between an area or relatively high
and low caliper extending for some distance in the machine direction; due to non uniform nip velocities
between hard and soft sections of the roll.
Core burst: Inter-layer slippage just above the core, often over the key way, which terminates an Air Shear
Burst. Core bursts are most often seen on core-supported unwinds and winders.
Burst Factor
The ratio of the bursting strength (expressed in g/cm2 ) and the substance of paper/paperboard
(expressed in g/m2) determined by standard methods of test.
Burst Index
The ratio of the bursting strength (expressed in kilo Pascal ) and the substance of paper/paperboard
(expressed in g/m2) determined by standard methods of test.
Burst Ratio
The ratio of the bursting strength (expressed in lb/inch2 ) and the substance of paper/paperboard
(expressed in lb/ream) determined by standard methods of test.
Bursting Strength
The resistance of paper to rapture as measured by the hydrostatic pressure required to burst it when a
uniformly distributed and increasing pressure is applied to one of its side.
Butt Joint
The joint resulting from making a butt splice by joining the ends of two webs of paper with a single sided
adhesive. The two webs are laid end to end without overlapping.
Butt Roll
A small diameter roll left at the end of a lot or job. It is sold as job lot or recycled.
C
C1S
Coated on one side of the paper.
C2S
Coated on both sides of the paper.
Calcined Clay
A product that results from heating of ordinary clay in a furnace, making it white and bulky.
Calcite
The most common crystalline form of calcium carbonate, including almost all ground calcium carbonate
and most PCC products.
Calcium Carbonate
CaCO3, a naturally occurring substance found in a variety of sources, including chalk, limestone, marble,
oyster shells, and scale from boiled hard water. Used as a filler in the alkaline paper manufacturing
process, calcium carbonate improves several important paper characteristics, like smoothness,
brightness, opacity, and affinity for ink; it also reduces paper acidity. It is a key ingredient in today's paper
coatings.
Calender
A stack of highly polished metal cylinders at the end of a paper machines that smoothes and shines the
paper surface as sheets pass through.
For more detail see Mark Your Calender by Wire & Fabrics
Calender Blackening
Coverage of calendered paper web with glazed translucent spots due to excessive calender roll heat,
calender pressure, poor and/or excessive and uneven moisture.
Calender Cut
Weak lines or fractures in paper that break easily under tension, caused by wrinkles going through the
calender stack of the paper machine.
Calender Spots
Paper defect usually indicated as a transparent spot in the sheet; caused by foreign material adhering to a
calender roll and being impressed into the sheet with each revolution.
Calendering
Passing paper web through a stack of calender rolls.
The main object of calendering is to impart the desired finish to paper.
Machine Calendering: Paper passes through one or more nips formed by a set of iron rolls.
Super-Calendering: Paper passes through one or more nips formed by steel roll and a fiber roll
made of compressed fibrous material.
Gloss Calendering: Paper passes through one or more nips formed by soft roll (e.g. rubber
covered) and highly smooth mirror like finish steel roll at high temperature.
Matt Calendering: Any calendering technique used to produce a smooth surface without a
considerable increase in gloss.
Friction Calendering: The calendering is achieved by speed differential between rolls. The paper
passes through one nip (2 steel rolls) or 2 nips (2 steel rolls separated by a fiber roll) in which
rolls are driven independently and speed variation may be from 10 to 30%.
Brush Calendering: The paper is pressed against a cylindrical brush by a backing roll or by web
tension. The circumferential speed of the brush is several times higher than the web speed.
Caliper
The thickness of paper usually expressed in thousandths of an inch in English system of units and in
millimetres in Metric system of units.
Camber
Larger diameter in the centre of a papermaking rolls (press & calender etc), compared to the ends, to
compensates the deflection of roll due to its own weight.
Cambium
In plants, layer of actively dividing cells between xylem (wood) and phloem (bast) tissues that is
responsible for the secondary growth of stems and roots (secondary growth occurs after the first season
and results in increase in thickness).
Cellulose Fiber
An elongated, tapering, thick walled cellular unit, which is the main structural component of woody plants.
Fibers in the plants are cemented together by lignin. In British English Fiber is spelled as Fibre. Thermal
conductivity of cellilose fiber varies from 0.034 to 0.05W/m K, making it a good insulator.
Chain of Custody
The process of tracking materials used within a manufacturing facility so that the source of raw materials
used to make specific end products can be identified. Commonly applied in the context of use of certified
fibre supplies.
Chain Marks
Also called chain lines or chains. Watermarks in paper that resemble impressions of a chain, running
parallel to the grain, approximately one inch apart. These watermark lines are found in laid papers.
Chalking
Improper drying of ink. Ink vehicle has been absorbed too rapidly into the paper leaving a dry, weak
pigment layer which dusts easily.
Check or Cheque Paper
A strong, durable paper made for the printing of bank checks or cheques.
Chelating Agent
An organic compound that forms more than one coordinate bond with metals in solution; organic
compound participating in chelation; e.g. EDTA and DTPA.
Chelation
A chemical complexing (forming or joining together) of metallic cations (such as iron) with certain
organic compounds, such as EDTA (ethylene diamine tetracetic acid); a reaction between a metallic ion
and an organic compound that removes the metallic ion from solution.
Chemical Ghosting
A light duplication of a printed image on the other side of the same sheet, created by chemical reaction by
the ink during the drying stages; also referred to as "gas ghosting.".
Chemical Oxygen Demand (COD)
The amount of oxygen consumed in complete chemical oxidation of matter present in waste water;
indicates the content of slowly degradable organic matter present. COD is easier to measure compared to
BOD (Biological Oxygen Demand).
Chemical Pulp
Pulp obtained from the chemical cooking or digestion of wood or other plant material.
Chemical Recovery
It is the process in which cooking chemicals are recovered.
Chemo-Thermo-Mechanical Pulp (CTMP)
Mechanical pulp produced by treating wood chips with chemicals (usually sodium sulfite) and steam
before mechanical defibration.
Chest
Vessel equipped with an agitating device for storing, collecting, mixing, blending and/or chemical
treatment of pulp suspension. Chest can be horizontal and or vertical. Tower are special type of chest
generally used in bleached plant to provide retention time and to provide down/upward flow out of pulp.
Chill Rolls, Cooling Rolls or Sweat Rolls
Rolls located immediately after heated or drying ovens on either paper making, coating, or printing
equipment, to lower the temperature of the web, and in the case of heat- set inks, to the "setting"
temperature of the inks. Can also be called "cooling rolls" or "sweat rolls."
China Clay
Natural mineral, consisting essentially of hydrated silicate of alumina, used as a filler or as a component
in a coating color. (Also see clay)
Chip
Wood chips produced by a chipper; used to produce pulp, fiberboard and particle board, and also as fuel.
Chipboard
A paperboard, thicker than cardboard, used for backing sheets on padded writing paper, partitions within
boxes, shoeboxes, etc.
Chipper
The machine that converts wood logs in to chips.
Chlorine Number
A test method to determine the bleach requirement of a pulp. It indicates the number of grams of chlorine
consumed by 100 g of pulp under specified conditions.
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.
Cigarette Paper
This light weight, unsized paper (grammage 18 to 24g/m2). It normally has approx. 30% calcium
carbonate as filler to control the burning rate and match it with tobacco burning rate. Very long fiber such
as jute, cotton etc is used to achieve high strength and porosity.
Clarifier
Basin where sludge is removed from treated effluent by settling.
Clay
A natural substance used as both a filler and coating ingredient to improve a paper's smoothness,
brightness, opacity and/ or affinity for ink.
Clear Cutting
A forestry/logging practice in which most or all trees in a harvest area are cut down.
Cloned Fiber
Wood raw material derived from trees that are genetically cloned species. Specifically refers to fiber from
fast growing, cloned tropical hardwood plantations (Eucalyptus and Acacia especially) in South America
and Asia, but also cloned softwood plantations in some areas of the world, particularly South America.
Cloned fiber has the advantages of being less costly than fiber from managed or natural forests, and
results in a more consistent supply to the pulping process.
Closed Loop Recycling
When a used product is recycled in to a similar product; a recycling system in which a particular mass of
material is remanufactured into same product.
Closed System
Papermaking system wherein white water is mainly re-circulated and not discharged as effluent.
Clot
Thick element composed of several entangled fibers. Its presence is harmful to the production process
and needs to be eliminated.
Clump
A knot of fibers resulting from improper separation of the fibers.
Coagulation
(1) A process whereby finely divided particles are made to combine to produce a particle capable of
settling. It is commonly done in the clarification of the mill water supply by chemical means. (2) The
clumping of particles in order to settle out impurities in mill supply and wastewaters by the use of lime or
alum.
Coarsenss
A property of pulp related to the refining, fiber perimeter, and wall thickness characteristics as it affects
the weight per unit length of the fiber.
Coarse Paper (also Industrial Paper)
Various grades of papers used for industrial application (abrasive, filter etc.) rather than cultural purposes
(writing, printing etc.)
Coat Weight
The amount of coating applied to base paper, expressed as pounds of air-dried coating on the surface of
a 25X38 in ream or grams per meter square.
Coated Paper
Term that applies to paper which has a special coating applied to its surface. Material such as clay,
casein, bentonite, talc, applied by means of roller or brush applicators; or plastics applied by means of roll
or extrusion coaters.
Coated White Top Liner
White liner that is coated to produce superior printability.
Coating
Process by which paper or board is coated with an agent to improve its brightness and/or printing
properties.
Coating Color
Mixture used to coat paper and board: contains pigment, binder, special additives and water.
Coating Color Kitchen
Section of Coating Plant where coating colour is prepared and mixed
Cobb Test
Measures paper's water absorption rate and is expressed as the amount of water pick-up per unit surface
area of paper by Tappi method T441. The test duration must be specified to properly know the absorption
rate. United Nations (UN) and Code of Federal Regulations require the 30-minute pick-up must be 155
grams per square meter or less for containerboard used in hazardous material transport.
Cockle Finish
Produced by air drying paper with controlled tension. This uneven surface is available in bond papers.
Cockling
When the surface of the paper has wave like appearance.
Cogeneration
It is the process to generate electricity from high pressure steam and using low and/or medium pressure
steam in the mill process.
Coir
Fiber derived from the outer husks of the coconut.
Cold Blow
Pressure ejection of cooked pulp from batch or continuous digesters after the pulp has been cooled to
below 100oC. The cooling step reduces damage to the fibers.
Color-fast papers
Colored papers that will not run when wet or fade under bright light.
Colored Kraft
Natural or bleached kraft paper to which a dye or pigment has been added.
Colored Pigments
These are water insoluble colored materials. They belongs in the category of fillers and loading material
but are colored and used in small quantity.
Pigments has no affinity to fiber and must be used in conjunction with alum or a cationic retention aid in
order to retain them.
Combined Deinking
Deinking process combining flotation and washing.
Composting
The controlled biological decomposition of organic material in the presence of air to form a humus-like
material
Compression Strength (CD or MD)
Can be referred to as ring crush or "STFI (stiffy)". The amount of force needed to crush paper resting on
its edge. Compression testers hold and support the paper specimen so as to emulate its position and
orientation in the walls of a corrugated container. Due to the corrugated board making process, paper
must support compressive loads orthogonal to their grain (a CD orientation). The test is unidirectional so
the paper orientation during testing must be known.
Coniferous Trees
Cone bearing and evergreen trees. Also known as soft wood trees. e.g. pine, spruce etc.
Pine Spruce
Consistency
The percentage of bone dry solids by weight in pulp or stock.
Consistency Regulator
A device or instrument used to regulate the consistency of the pulp on-line. Regulator works only in
reducing the consistency i.e. add water, but can't remove water or thicken.
Construction Paper
Sheathing paper, roofing, floor covering, automotive, sound proofing, industrial, pipe covering, refrigerator,
and similar felts.
Containerboard
The paperboard components (linerboard, corrugating material and chipboard) used to manufacture
corrugated and solid fiberboard. The raw materials used to make containerboard may be virgin cellulose
fiber, recycled fiber or a combination of both.
Continuous Pulping
Production of pulp in continuous digester as compared to a batch digester.
Contraries
Unsuitable material found in wastepaper which must be removed from the pulp before making it into
paper, e.g. paperclips, string, plastics.
Contrast
The degree of difference between light and dark areas in an image. Extreme lights and darks give an
image high contrast. An image with a narrow tonal range has lower contrast.
Converting
The operation of treating, modifying, or otherwise manipulating the finished paper and paperboard so that
it can be made into end-user products.
Cooking
Reacting fibrous raw material with chemical under pressure and temperature to soften and or remove
lignin to separate fibers.
Cooking Liquor
Liquor made up of selected chemicals and used for cooking pulp. e.g. cooking liquor in kraft pulping
mainly consist of NaOH and Na2S.
Cooling Cylinders or Cooling Drums
Water cooled cylindrical metal vessel over which dry paper web after dryers is passed to cool the paper
before calendering..
Copier Paper or Laser Paper
Lightweight grades of good quality and dimensionally stable papers used for copying correspondence
and documents. For detailed characteristics of copier/Laser paper, please visit Paper Needs of
Xerographic Machines (A Summary) by Chuck Green
Copper Number
It is the measure of degree of fiber degradation. It is weight of copper in grams reduced to cuprous state
by 100 grams of pulp.
Cord
Pulpwood volume measurement indicating a pile measuring 4 ft x 4 ft x 8 ft, equaling 128 ft³ (3.62 in³ ). A
long cord measure 4ft x 5ft x 8ft equaling 160 ft3. Also see cunit
Core
Fibrous tube used to wound paper for shipment.
Core Plug
Metal, wood, particleboard, or other material plugs which are driven into the ends of the paper core of
finished roll to prevent crushing of the core.
Corona Treatment
An electrostatic treatment that reduces the surface tension of a substrate (e.g., a polycoated substrate)
to ensure adhesion of ink and glue.
The Corona treatment involves high voltage, high frequency electricity discharged from an electrode when
it pours through the polycoated board increases the surface energy of the board to better receive inks or
glue.
Corrugated Board
Usually a nine-point board after if has passed through a corrugating machine. When this corrugated board
is pasted to another flat sheet of board, it becomes single-faced corrugated board; if pasted on both
sides, it becomes double-faced corrugated board or corrugated (shipping) containerboard.
Open Face Single Face Single Wall
Cotton Fiber
Cotton is a natural fiber and is one of the strongest and most durable fibers known to man. Papers
manufactured of cotton fiber will last longer and hold up better under repeated handling and variant
environmental conditions than paper made from wood pulp. Generally, given reasonable care, one can
expect one year of usable life for every 1% of cotton contained in the sheet. Typically cotton fiber papers
are made of either all cotton fiber (100% cotton) or a blend of cotton and wood pulp.
Cotton "fibers" are made from unicellular hairs that grow out from the surface of the seed immediately
after fertilization. The hairs are twisted into usable thread which is tough and strong. Cotton hairs (lint)
of tetraploid (4n) species may be up to 50 mm long. In the cotton gin, fine brushes pull the lint off the
seed by drawing it through holes too fine for the seeds to pass. Cotton thread is spun from countless
billions of microscopic hairs covering the surface of cotton seeds, each hair up to 50 mm (2 inches) in
length. The total length of hairs in a single cotton boll (one seed capsule) may exceed 300 miles.
Imagine how many miles of cotton hairs are in a standard 500 pound bale. Cotton is the textile
produced in the largest volume worldwide. (From http://waynesword.palomar.edu/traug99.htm )
Crescent Former
Sheet forming section in a tissue machine, with the pulp suspension jet-out of the headbox flowing
between a felt and a wire both moving at the same speed.
Crinkles
A defect in linerboards caused by the separation of the liner ply and/or the formation of fissures (cracks)
in the surface of the liner during creasing.
Cross Folds
Paper with cross folds have two or more folds going in different directions, typically at right angles.
Primarily used in reference to bookwork , cross folds also describes quarter-folds or 8-panel French folds.
Cross-machine Direction
A direction perpendicular to the direction of web travels through the paper machine.
Crystallization
A condition of a dried ink film, which repels another ink printed on top of it.
Culls
Off spec paper sold as lower quality product or recycled.
Cunit
A term used in the measurement of pulpwood, i.e. 100 cubic feet of solid wood, bark excluded. One cunit
corresponds to 2.83 cubic meter of wood. Also see Cord
Curl
Tendency of paper by itself to bend or partly wrap around the axis of one of its directions. For more
details on Curl, please read Curl Basics by Chuck Green.
Customark
A customark is a watermark made with a rubber printing plate treated with a tranparentizing solution that
leaves a mark in the paper. This process produces a wire appearance in which the mark is lighter than the
surrounding paper. It can be produced in smaller quantities and at a lower price than a genuine
watermark, which requires a dandy roll.
Cut Sheet
Paper cut in sheets (letter, legal, A, B or any other standard size) to be used in printer, photocopier, fax
machines etc.
Cutin
A wax like substance found in plant cell walls.
Cutter
A machine in the Finishing House of a paper mill, used for converting paper from reel to specific sheet
sizes.
Cutter Dust
Small loose paper particles which chip out of the edges of a sheet of papers as it is cut by the chopping
blade and/or disc knives on a sheet cutter.
Cutting (Refining)
A refining or beating action that splits the fibers in to two or more pieces.
Cylinder Mould or Cylinder Machine
It is a type of papermaking machine. Wire-covered cylinders are rotated through a vat of pulp, and paper is
formed as the water drains from the cylinder. Cylinder machines are used primarily to manufacture
paperboard. Multi-cylinder machines produce multi-layered paperboard (one layer for each cylinder).
D
Damp Streaks
Streaks caused by uneven pressing or drying during paper manufacturing.
Damping Rolls
A type of roll usually located just ahead of a coater or at the end of a paper machine. It is used to cool the
sheet by being operated at a temperature that is low enough to cause moisture to condense on its
surface and slow up the drying.
Dampening
The process of keeping the non-image areas of lithographic plates to be ink repellent by applying aqueous
Fountain solution to the plate from the Dampening system.
Dancing Roll
Usually, a weighted roll that rides on a web of paper between two fixed points (for example, between an
unwinding roll of paper and an impression or coating nip) to take up slack and maintain a uniform web
tension.
Dandy Roll
A hollow wire covered roll that rides on the paper machine wire and compacts the newly formed wet web
to improve the formation and if required to impart watermark or laid finish the paper.
Dandy Roll
Deaeration
Debarking Drum
Large rotating cylinder in which pulpwood logs are tumbled against one another to remove the bark.
Debarking
The process of removing bark from tree my mechanical means. Click here to see Debarking Image 1 and
Debarking Image 2
Debarking Drum
Large rotating cylinder in which pulpwood logs are tumbled against one another to remove the bark.
Deboss
To press an image into paper so it lies below the surface.
Debossing
Pressing letters or illustrations into a sheet of paper using a metal or plastic die to create a depressed
(debossed) image.
Deciduous Trees
Broad leafed or hardwood trees which lose their leaves in fall such as birch, maple etc.
Birch Maple
Decker
A drum type filter used for pulp thickening.
Deckle
The width of the wet sheet as it comes off the wire of a paper machine. Also defied as the wood frame
resting on or hinged to the edges of the mould that defines the edges of the sheet in handmade
papermaking or strap or board on the wet end of a paper machine that determines the width of the paper
web.
Deckle Edge
The untrimmed, feathery edges of paper formed where the pulp flows against the deckle.
Decomposition
Change in chemical composition of organic matters due to the action of aerobic or anaerobic
microorganisms.
Deculator
A device that removes entrained and dissolved air from dilute stock furnish by applying vacuum as the
stock is sprayed into an open chamber, usually at the outlet of cleaners.
Decurler
A device on a web press or sheeter used to remove paper curl.
Defibration
Separation of wood fibers by mechanical and/or chemical means.
Deflaker
Deflaker mechanically treat the fiber flakes and bundles of fibers in the stock in order that they are broken
down into individual fibers in a suspension if possible. This is done for a number of reasons and in a
number of positions within the system. It can be installed to reduce remaining flakes after a pulper, in the
broke system to reduce flakes going back to the machine from the broke pulpers and can also be used in
the final stages of a screening system in a recycled fiber line to treat the concentrated rejects and the
flakes contained within it.
Deflour
Screening of pulp slurries to remove short fibers and small fiber particles.
Defoamer or Anti-foam
Chemical additives used at wet end to reduce or eliminate tendencies of the machine white water to
foam. For more details
Degree of Polymerization (DP)
As applied to cellulose, refers to the average number of glucose unit in each cellulose molecule of a pulp
sample. Usually determined by the CED viscosity test.
Deinked Pulp (DIP)
Paper pulp produced by deinking of recovered paper
Deinking
The process of removing inks, coatings, sizing, adhesives and/ or impurities from waste paper before
recycling the fibers into a new sheet.
Deinking Cell
A vessel or chest used to treat recycled paper with chemical to remove ink.
Delamination
The separation of the layers of a multiplex paper/paperboard/corrugated board.
Delignification
The removal of lignin, the material that binds wood fibers together, during the chemical pulping process.
Deliquescent
Material that has the ability to absorb enough moisture from the surrounding atmosphere to revert it to a
liquid form. Examples of deliquescent include calcium chloride and ammonium nitrate.
Densitometer
A sensitive photoelectric instrument that measures the density of photographic images or of colors. Used
in quality control to accurately determine the consistency of color throughout the run.
Depithing
The separation of the pith from the fiber so that bagasse can be used as a source of pulp for
papermaking.
Deresination
Reducing the resin (pitch) content of wood prior to cooking either by storage or using bleaching
chemicals to reduce the resin content in pulp.
Dewater
Process of water removal from slurry.
Digester
The reaction vessel in which wood chips or other plant materials are cooked with chemical to separate
fiber by dissolving lignin.
Digital Printing
1. Printing by imaging systems that are fed imaging information as digital data from pre-press systems.
2. Computer –to-plate Systems, which use printing plates, or other images carriers that do not require
intermediate films.
3. Computer-to-print (Plateless): Systems that produce reproductions directly on the substrate without the
need for intermediate films or plates
A. Electronic printers: Electrophotographic printers, for black or single color, used for short-run variable
information and on-demand book publishing.
B. Color copiers: Usually Electrophotographic printers, for spot or four color process printing, used for
making one or several copies of spot or four color process subjects.
C. Electronic printing systems: Electrophotographic, magnetographic, monographic, field effect, ink jet or
thermal transfers printing. For One-colour, four color process or up to six-color printing. Used for some
degree of variable information, on-demand. Examples of use are direct mail, temporary product labels for
trade shows, billboard posters and the like.
Dimensional Stability
The ability of paper or paperboard to maintain size. It is the resistance of paper to dimensional change
with change in moisture content or relative humidity. Dimensional stability is essential for keeping forms
in registration during printing and keeping sheets from jamming or wrinkling on press or in laser printers.
For more details on Dimensional Stability, please read Dimensional Stability Notes by Chuck Green
Dioxin
A group of 75 chlorinated compounds. Dioxins are formed in a complex process, where chlorine
combines with other additives during bleaching..
Direct Cooking
Batch cooking in which digester contents are heated by blowing steam directly into the digester.
Direct Dye
Dye molecules that are sufficiently large and planar that they tend to remain on a fiber surface without
need of a fixative. Direct dyes have moderate lightfastness but duller shades
Directionality
Dependency of a given paper property on the orientation of the fiber in paper e.g. CD or MD.
Dirt
Dirt in paper consists of any imbedded foreign matter or specks, which contrast in color to the remainder
of the sheet.
Dirt Count
The average amount of dirt specks in a specific size of paper area. Both virgin sheets and recycled sheets
have "dirt," although recycled paper usually has a slightly higher dirt count than virgin paper. However, it
rarely affects recycled paper's quality and use.
Dirty Blow
When a batch digester is discharged in to a blow tank with uncooked chip, pulp or liquor remaining in
digester or blow line.
Dispersion
A distribution of small particles in a medium. It also describes the uniform suspension of fibers in water
for wet forming.
Following the deinking process of waste papers, residual ink particles are dispersed into tiny bits that are
usually invisible to the eye. Bleaching the fibers helps to remove the last of the inks and improve paper
brightness.
Dispersants
Substances such as phosphates or acrylates that cause finely divided particles to come apart and remain
separate from each other in suspension.
Displacement Washing
An event of pulp washing in which washing liquid displaces free liquor from a pulp bed in order to improve
the washing; enables washing with reduced amount of water.
Dissolving Pulp
A high purity special grade pulp made for processing in to cellulose derivatives including rayon and
acetate.
Doctor Blade
Thin metal plate or scraper in contact with a roll along its entire length to keep it clean. Blades are also
used for creping.
Document Paper
Document paper is paper with a high ageing resistance. It is woodfree but may also contain rags or be
fully made from rags and is used for documents that have to be preserved for a longer period.
Double Coating
Coating of paper or paperboard twice on one or both sides.
Down Cycling
Every time cellulose fibers are recycled they deteriorate slightly and become contaminated, so the new
product is of lower quality than the original product which went to form the waste; the progressive
deterioration of fibers means that there is a limit to the number of times they can be recycled, thus the
term down cycling is used as a more accurate description of recycling.
Drainage or Dewatering
Removal of water from wet web during formation of paper sheet.
Draw
Difference in speed between two adjacent section of the paper machine.
Dregs
The solids which settle down in the clarifiers in the Causticizing process.
Drum Reel
The reel drum (also called a "pope reel") is motor driven under sufficient load to ensure adequate tension
on the sheet coming from the calendars. The web wraps around the reel drum and feeds into the nip
formed between the drum and the collecting reel.
Drum Washer
One type of pulp washers; uses pressure gradient and filtration for dewatering and displacement.
Dry Coating
Coating method in which a binder is applied to the paper surface followed by dry coating pigment.
Dry End
That part of the paper machine where the paper is dried, surface sized, calendered and reeled.
Dry Line
The dry line is the location on a Fourdrinier paper machine forming section where the appearance of the
wet web of paper changes abruptly. Before the dry line the furnish has a glossy, wet appearance. After the
dry line the wet web appears dull. The optical change is related to the effect of fibers poking through the
air-water interface. On a well-adjusted paper machine the dry line ought to be straight. Increased refining
and lower freeness of the pulp tend to move the dry line in the direction of the couch. Chemicals that
promote drainage tend to move the dry line in the direction of the slice.
Dry Offset
Uses a rotary letterpress plate on an offset press. Because the image is relief, the method requires no
dampening. Image is transferred to a rubber blanket, then to paper.
Dryer Felt
A continuous cotton and or synthetic belt and used in the dryer section of a paper machine to press and
maintain positive contact of the web against the surface of the dryer cylinder.
Fabric Press
Paper machine wet press that uses a special multiple weave fabric belt sandwiched between the regular
felt and the rubber covered roll, increasing the capacity to receive and remove water from the nip between
the rolls.
Falling Film Evaporator
A type of heat exchanger used for concentrating a solution consisting of a non-volatile solute and a
volatile solvent; solution flows downward on the heat exchange surface by gravity; the heat exchange
surface is typically a bundle of plates, lamellas or tubes; commonly used in pulp mills and chemical
recovery process.
Fan-out
A dimensional change in paper associated with its passage through a printing unit. In web offset printing
it is the increase in web width after each blanket impression.
Fan Pump
A high flow rate, low head pump used to pump diluted stock to paper machine headbox.
Fanfold
Continuous multiple ply form manufactured from a single wide web which is folded longitudinally.
Feathering
The tendency of liquid ink to spread along the paper fibers so that the image produced does not have
sharp, clean edges.
Felt
A woven cloth used to carry the web of paper between press and dryer rolls on the paper machine.
Felt Filling
Undesirable accumulation of particulate matter within the void spaces of press felts.
Felt Finish
Surface characteristics of paper formed at the wet end of a paper machine, using woven wool or synthetic
felts with distinctive patterns to create a similar texture in the finish sheets.
Felt Mark
Imprint left on the paper by one or more of the felts used in making the paper. The mark may be wanted or
unwanted and special effects can be introduced in this way.
Felt Side
The side of the paper which does not touch the wire on the paper machine. The "top side" or felt side is
preferred for printing because it retains more fillers.
Fiber or Fibre
The slender, thread-like cellulose structures that forms the main part of tree trunk and from separated and
suitably treated, cohere to form a sheet of paper.
Softwood Fiber Fiber Internal Structure
Ink absorbency (Uncoated paper) Gets more uniform Gets less uniform
Initially, fillers were used o replace more expensive fibers without detrimentally affecting the properties
of the sheet. Since then, with increasing sophistication of papermaking, the role of fillers has
dramatically changed. Although the financial value of using fillers still exists, a wide range of optical
and physical properties can be imparted to the sheet.
In addition, the use of fillers also affects such parameters as chemical usage, drying and formaion as
well as brightness and printability.
Filter Paper
Unsized paper made from chemical pulp, in some cases also with an admixture of rags, sometimes with a
wet strength finish. Filtration rate and selectivity, which are both dependent on the number and the size of
the pores, can be controlled by specific grinding of the pulps and creping.
Filtrate
The effluent from the washing or filtering process.
Fines
Small particles fiber defined arbitrarily by classification.
Fine Papers
Uncoated writing and printing grade paper including offset, bond, duplicating and photocopying.
Finish
The surface characteristic of a sheet created by either on-machine or off-machine papermaking
processes. Popular text and cover finishes include smooth, vellum, felt, laid, and linen.
Finishing
The trimming, winding, rewinding and packing of paper rolls or trimming, cutting, counting and packing of
paper sheets from parent roll.
Finishing Broke
Discarded paper resulting from any finishing operation.
First Pass Retention
First-pass retention gives a practical indication of the efficiency by which fine materials are retained in a
web of paper as it is being formed. First-pass retention values can be calculated from just two
consistency measurements, the headbox consistency, and the white water consistency. There is a very
wide diversity of first-pass retention on different paper machines, from less than 50% to almost 100%.
The key rules that papermakers follow are that (a) first-pass retention should have a steady value, and (b)
that value should be high enough to avoid operational problems or an excessively two-sided sheet. Some
operational problems that can be caused by low values of first-pass retention are increased frequency of
deposit problems, filling of wet-press felts, poor drainage, and unsteady drainage rates and sheet
moistures.
Fish Eye
A paper defect appearing as glazed, translucent spot caused by slime, fiber bundles, and/or improperly
prepared chemical additives in the stock.
Fixative
An additive having the tendency to help retain dye material on fiber surfaces, usually because of a strong
positive charge.
Flag
A strip of paper protruding from a roll or skid of paper. May be used to mark a splice in a roll of paper or
used to mark off reams in a skid.
Flame Resistant
Treatment applied to kraft paper to make it resistant to catching on fire (not fire proof—will char but not
burst into flame).
Flat Crush of Corrugated Board
A laboratory test (Tappi T808 or T825) of a single wall combined board specimen to measure its
resistance to crushing forces from conversion and handling. Test can also be an indicator of flute
formation and the presence of crushed or leaning flutes.
Flashing
Spontaneous boiling and cooling of a liquid caused by the reduction of pressure below the vapor pressure
of the liquid. Flashing occurs in blow tank during blowing.
FlyLeaf/Shaving
Trim scrap from printing operation.
Flexography
A form of rotary letterpress using flexible rubber or photopolymer plates.
Flexural Rigidity
The measurement of a combined board resistance to flexing. Combined with ECT box perimeter and flute
type, it is key to predicting box compression resistance or static load resistance (Tappi T566).
Flocculation
A tendency for fibers to collect together in bunches in the presence of flow, and especially in the presence
of retention aids; the same word also refers to the action of high-mass polymers in forming bridges
between suspended colloidal particles, causing strong, relatively irreversible agglomeration.
Flotation Cell
Main equipment of Flotation Deinking, Large number of tiny air bubbles are injected into the cleaned pulp,
the free ink particles attach themselves to these bubbles and float to the surface where it is skimmed off
and removed.
Flotation Deinking
Using flotation method for removing ink from paper during the de-inking process.
Flotation Dryer
Non contacting dryer used in pulp drying or coating applications, drying is achieved by passing sheet
between two dryer hoods where hot dry air is impinged onto the sheet and the moisture is evaporated and
removed by an air system.
Flowspreader
Front end of the paper machine whose objective is to distribute the papermaking fiver uniformly across
the machine from back to front.
Fluff Pulp
A chemical, mechanical or combination of chemical/mechanical pulp, usually bleached, used as an
absorbent medium in disposable diapers, bed pads and hygienic personal products. Also known as
"fluffing" or "comminution" pulp
Fluorescent Dye
A coloring agent added to pulp to increase the brightness of the paper. It may give a slight blue or green
cast to the sheet.
Fluorescent Inks
Printing inks that emit and reflect light. Generally, they are brighter and more opaque than traditional inks,
but they are not color fast, so they will fade in bright light over time. Their metallic content will also affect
dot gain and trapping.
Fluorescent Whitening Agent
Also referred to as an "optical brightener." A chemical compound when expose to a light containing an
ultraviolet component will absorb and re-emit light in the blue spectrum or in other words fluoresce.
FWA's will enhance brightness and blueness quality of white paper.
Flute
One of the wave shapes pressed into corrugated medium. Flutes are categorized by the size of the wave.
A, B, C, E and F are common flute types, along with a variety of much larger flutes and smaller flutes.
Fluting
Waves or corrugation in heat-set web offset prints that runs in the press direction.
Flyleaf
Leaf or sheet of paper, at the front and back of a casebound book that is the one side of the end paper not
glued to the case.
Flying Paster
A device used to splice rolls of paper together during the converting or printing process without having to
stop the equipment.
Foamboard
C1S paperboard designed for lamination to a foam backing for point-of-purchase displays, posters, and
signs.
Foil or Hydrafoil
The flat strip used to support wire. Only the leading edge of the wire touches the foil. Foil helps in
removing water by creating gentle suction and also doctor the water removed in previous section. Two
most common types of foils are 1) Gravity Foils, which have a flat top, exert highest vacuum near the tail
of the foil and 2) Step Foils, which have a small vertical step soon after the foil toe, exert the highest
vacuum shortly after this step.
Folding
Doubling up a sheet of paper so that one part lies on top of another. Folding stresses the paper fibers. To
create a smooth, straight fold, heavy papers like cover stocks and Bristol need to be scored before they're
folded.
Folding Boxboard
Single or multi-layer paperboard made from primary and/or secondary fibers, sometimes with a coated
front, used to make consumer packaging (cartons).
Folding Strength or Folding Endurance
Folding strength is most important in currency paper. Multiple fold strength is also important for paper
used in books, maps, and pamphlets. It's far less important in one-fold greeting cards or envelopes, where
fold cracking is the vital consideration. Folding endurance or strength is measured and reported in
numbers.
Formation
The dispersion of fibers in a sheet of paper. The more uniform and tightly bound the fibers, the better the
sheet will print and look. Close Formation - Uniform distribution of fibers. Cloudy formation: A spotty,
non-uniform dispersion of fibers, the opposite of close formation.
Forming Board
Forming Board is the leading forming unit under the fabric closest to the slice. The stock jet velocity, the
impingement angle and the position of the impingement onto the forming board will determine the water
removal and the activity produced at this point. Modern Forming Boards are stepped to create suction at
high speeds – this greatly enhances the formation.
Fourdrinier
Named after its inventor, the Fourdrinier papermaking machine is structured on a continuously moving
wire belt on to which a watery slurry of pulp is spread. As the wire moves, the water is drained off and
pressed out, and the paper is then dried.
Free Stock
Unrefined stock. Stock that, when drained under gravity, parts easily with the water of suspension
Freeness
A term used to define how quickly water is drained from the pulp. The opposite of freeness is slowness.
Freeness or slowness is the function of beating or refining. Freeness and slowness reported in ml CSF
and degree SR respectively are also the measurement of degree of refining or beating.
Freesheet
Paper that is free of mechanical wood pulp, which is true of virtually all fine printing papers.
French Fold or cross fold
A sheet printed on one side and folded first vertically and then horizontally to produce a four-page folder.
Gatefold
Two or more parallel folds on a sheet of paper with the end flaps folding inward.
Ghosting
Variation in ink gloss, density or color that are not part of the original design, but appear as a repeat or
ghost image associated with another area of the copy.
Glassine Paper
A translucent paper made from highly beaten chemical pulp and subsequently supercalendered.
Glazed Paper
Paper with high gloss or polish, applied to the surface either during the process of manufacture or after
the paper is produced, by various methods such as friction glazing, calendering, plating or drying on a
Yankee drier.
Gloss
The property that's responsible for a paper's shiny or lustrous appearance; also the measure of a sheet's
surface reflectivity. Gloss is often associated with quality: higher quality coated papers exhibit higher
gloss.
Gloss Mottle
Blotchiness or non-uniformity in the paper's gloss (unprinted or printed). Typically only visible at certain
viewing angles. Usually attributable to poor formation and heavy calendering.
Grade
Papers are differentiated from each other by their grade. Different grades are distinguished from each
other on the basis of their content, appearance, manufacturing history, and/or their end use.
Grain
The direction in which most fibers lie in a sheet of paper. As the pulp slurry moves forward on the
papermaking machine's formation wires, the fibers tend to align themselves in the direction of movement.
Binding books parallel to the grain allows for a smoother fold then working across the grain. Grain
direction of sheet fed papers is usually indicated by underlining the number, e.g., 23" X -35". On a web
press, the grain direction should run along the length of the paper web.
Grain Long
Grain running lengthwise along a sheet of paper.
Grain Short
Grain running widthwise along a sheet of paper.
Grammage
Weight in grams of one square meter of paper or board (g/m2); also basis weight.
Granting
Uneven staining of fibers in pulp, usually due to a very high affinity of dye for fiber, together with
insufficient dilution and/or poor mixing.
Granite Finish
Paper to which multi-colors of fibers has been added to create a mottled surface that somewhat
resembles the texture or appearance of granite is said to be granite finish. Although many kinds of paper
can have a granite finish, it is often used for letterhead and envelopes.
Gravure
A printing process that uses intaglio, or recessed, image carriers. The image carrier, which is flat or
cylindrical, moves through an ink pool. A blade scrapes excess ink off the plane of the plate, leaving ink in
the recessed wells. A second cylinder presses the paper onto the plates, where it picks up ink from the
wells. The high speed of gravure presses and the durability of the metal intaglio plates make gravure an
economical printing method suitable for large print runs (more than two million copies).
Gravure Paper
Paper for gravure printing that has very low print roughness and good wettability of gravure inks.
Gray Board
A homogeneous board made usually of mixed waste papers with or without screenings and mechanical
pulp on a continuous board machine, in thickness less then 1 mm.
Greaseproof Paper
A protective wrapping paper made from chemical wood pulps, which are highly hydrated in order that the
resulting paper may be resistant to oil and grease.
Greenfield Mill
Mill or production facility built on undeveloped site.
Green House Gases
Gases that provide an insulating effect in the earth's atmosphere, potentially leading to global climate
change. These gases include carbon dioxide, methane, nitrous oxide, ozone, and water vapor.
Green Liquor
The liquor that results when the inorganic smelt from the recovery furnace is dissolved in water is called
"green" liquor.
Green Paper
Immature paper which has not been conditioned or had the opportunity to mature naturally.
Grinder
A machine in which logs are defibrated against a revolving grindstone.
Groundwood Papers
A general term applied to a variety of papers made with substantial proportions of mechanical wood pulp
together with bleached or unbleached chemical wood pulps (generally sulfite), or a combination of these,
and used mainly for printing and converting purposes.
Groundwood Pulps
A mechanically prepared (by grinding wood logs against a rough surfaced roll rotating at very high speed)
coarse wood pulp used in newsprint and other low cost book grades where it contributes bulk, opacity,
and compressibility. Groundwood pulp is economical since all the wood is used; however, it contains
impurities that can cause discoloration and weakening of the paper.
Guar Gum
A natural polymer that is used as a dry-strength additive, often as a cationic derivative.
Guillotine
A machine used to trim stacks of paper, which works the same way the original French guillotine worked.
A cutting blade moves between two upright guides and slices the paper uniformly as it moves downward.
Gurley Porosity
A method to measure the air permeability of paper by TAPPI method T536. See "Air permeability."
H
H Factor
It is the area under the curve when relative reaction rate is plotted against cooking time.
Half Fold
The half fold is commonly used for brochures and greeting cards. For cover weight paper, a score is
usually required to produce a smooth folded edge.
Half + Letter Fold
This fold is perfect for newsletters. An 11" x 17" sheet folded this way has only one open side and fits into
a #10 envelope. The newsletter looks good and is easy to handle. For picture of this type and other fold
please visit http://www.bradenprint.com/pdf/Folds-IS.pdf
Half Tone
Picture with gradations of tone, formed by dots of varying sizes in one color.
Handmade Paper
A sheet of paper, made individually by hand, using a mould and deckle.
Hard Cook
Undercooked pulp with respect to target conditions.
Hard Pulp
Chemical pulp with a high lignin content.
Hard Sized Paper
Paper treated with high degree of internal sizing.
Hardwood
Wood from trees of angiosperms class, usually with broad leaves. Trees grown in tropical climates are
generally hardwood. Hardwood grows faster than softwood but have shorter fibers compared to
softwood.
Head Box or Flow Box or Breast Box
The part of the paper machine whose primary function is to deliver a uniform dispersion of fibers in water
at the proper speed through the slice opening to the paper machine wire.
Heart Wood
The dark colored , center of a tree trunk, consisting of dormant wood.
Heat Embossing/Thermography
Heat embossing is done with embossing powder and a heat tool. The powder becomes liquid when
heated and then quickly dries hard when it cools. The end result of heat embossing is a raised surface on
the paper. This process is actually called "thermography" in the printing world.
Herbaceous Plants
Non-woody species of vegetation, usually of low lignin content such as grasses.
Hickey
An irregularity in the ink coverage of a printed page. Hickeys are caused by paper or pressroom dust, dirt,
or pick out on the printing blanket, all of which prevent the ink from adhering to the paper surface.
High Finish
Smooth finish applied to paper to improve the printing surface.
Hog Fuel
A mixture of bark and other wood waste usually produced by sawmills; burned to produce energy and
steam.
Hogged Paper
Paper that has been mechanically torn or ripped to reduce its original size.
Hold Out
Resistance of paper surfaces to the absorption of ink. High Hold Out offers higher resistance to ink
absorption. Regular Hold Out allows greater ink absorption.
Holocellulose
The total carbohydrate fraction of wood — cellulose plus hemicellulose.
Hologravure
Printining process by which great continuous 3D depth is achieved using textures and patterns.
Hood
A hood covering the paper machine drying section and designed for moist air removal.
Hot Melt
A type of glue or adhesive applied while hot/warm.
Hot Groundwood Pulp
Mechanical pulp produced by grinding logs that have been pre-treated with steam.
Hydration
The prolonged beating or refining of cellulose pulp in water to reduce it to a semi-gelatinous mass.
Hydrogen Peroxide Bleaching
A method in which pulp is bleached in an alkaline environment with hydrogen peroxide (H2O2),
sometimes using oxygen reinforcement. The method considerably reduces the need for chlorine-
containing chemicals in the final bleaching of chemical pulps.
Hydrophilic
Having strong affinity for water.
Hydrophobic
Lacking affinity for water.
Hydropulper
An equipment used to slush broke/paper in to pulp.
Hygroexpansivity
That property of a material which causes it to expand or contract when its moisture content is changed;
as in paper, when the relative humidity of the surrounding atmosphere is changed.
Hygroscopic
Having the property to absorb water vapor from the surrounding atmosphere. Most of the papers (except
glassine, greaseproof or wet strength etc.) are hygroscopic in nature.
Hysteresis (Paper moisture)
That property of cellulose fibers, and therefore paper, that allows the percent moisture content at
equilibrium with a specified relative humidity, to be dependent upon the most recent past relative humidity
exposure; as if paper had a "memory," with the equilibrium moisture content closer to the most recent
higher or lower relative humidity exposure, i.e., two pieces of paper that were last exposed respectively to
high and low relative humidities, will have higher and lower moisture contents when brought into
equilibrium at 50% relative humidity; dimensions will also vary accordingly.
I
Imbibition
The absorption of liquid by a fiber without a corresponding increase in volume.
Impact Printing
A paper printing process that physically applies ink to the paper surface.
Impregnation
Process of treating a sheet of paper with a chemical or wax so that the treatment penetrates into the
paper.
Impression Cylinder
The cylinder or flat bed of a printing press that holds paper while an inked image from the blanket is
pressed upon it.
Impression Watermark
Semi-genuine watermark made in the paper machine press section using engraved rolls while the web is
still wet.
Index Paper
A stiff, inexpensive paper with a smooth finish. The high bulk but low weight of this paper makes it a
popular choice for business reply cards.
Indirect Greenhouse Gases
Greenhouse gas emissions relating to an industrial process but not directly generated by it. Measurement
of such emissions, as per the World Resources Institute’s Scope 2 definition, is commonly limited to
those associated with purchased energy.
Industrial Papers
A very general term, which is used to indicate papers manufactured for industrial uses as opposed to
cultural purposes. Thus, building papers, insulating papers, wrapping papers, packaging papers, etc.
would be considered industrial papers.
Industrial Waste Papers
Waste paper created as a by-product of industry such as scrap, trimmings and cuttings from printing and
converting plants.
Infra Red Drying
Electric or gas infra red dryers used to initially achieve immobilization of the fluid coating and commence
the drying process.
Ink
Printing inks are made up of pigment, pigment carrier and additives formulated to reduce smudging,
picking and other printing problems associated with ink. The choice of ink depends on the type of paper
and printing process.
Ink Absorption
A paper's capacity to accept or absorb ink.
Ink Coverage
The portion of the total surface area of the paper which is covered by ink. The portion of the coverage
usually is expressed in terms of percent of ink coverage.
Ink Holdout
The way the ink pigment sits on the surface of the paper. Strong ink holdout results in a sharp, bright
image.
Ink Jet Printing
Printing process of an image or text by small ink particles projected onto the paper surface.
Ink Tack
The body or cohesiveness of ink. The measure of tack as the force required to split an ink film.
Insect Resistant
Paper treated with insecticide compounds to make it resistant to insect attack.
Insider Liner
The liner bonded to the medium at the single facer. Called inside liner because it is the inside facing of a
corrugated box. Also called the single face liner.
Insulating Board
A type of board composed of some fibrous material, such as wood or other vegetable fiber, sized
throughout, and felted or pressed together in such a way as to contain a large quantity of entrapped or
"dead" air. It is made either by cementing together several thin layers or forming a non-laminated layer of
the required thickness. It is used in plain or decorative finishes for interior walls and ceilings in thickness
of 0.5 and 1 inch (in some cases up to 3 inches) and also as a water-repellent finish for house sheathing.
Desirable properties are low thermal conductivity, moisture resistance, fire resistance, permanency,
vermin and insect resistance, and structural strength. No single material combines all these properties
but all should be permanent and should be treated to resist moisture absorption.
Intaglio
A method of printing in which an image or letter is cut into the surface of wood or metal, creating tiny
wells. Printing ink sits in these wells, and the paper is pressed onto the plate and into the wells, picking up
the ink.
1. Gravure is considered an intaglio printing process.
2. In papermaking, watermarking from countersunk depressions in the dandy roll to provide a whiter or
denser design instead of increased transparency.
Integrated mill
A mill which starts with logs or wood chips and first produces wood pulp which it then processes to make
paper or board.
Intermittent Board Machine
A machine for producing sheets of thick board by winding the web formed on a Fourdrinier wire or
cylinder mould (s) around a making roll to form a sheet consisting of several layers. When the thickness is
sufficient the layers are cut, so forming a sheet which is removed from the machine for drying and any
further processing.
Internal Bonding Strength
Determines how strongly the coating is fused to the body stock. Caused by long periods of hydration,
paper with high internal bonding strength resists picking during the printing process
Internal Fibrillation
Loosening of internal bond within a fiber.
Internal Sizing
Occurs when sizing materials are added to the water suspension of pulp fibers in the papermaking
process. Also known as Beater, or Engine sizing.
International Paper and Board Sizes
Also known as ISO sizes are widely used in metric countries. ISO standards are based on a rectangle
whose sides have a ratio of one to the square root of 2 (1.414). No matter how many times a sheet of
these proportions is halved, each will retain the same constant proportions. There are three ISO series A,
B, and C.
The A Series: The A series is for general printed matter including stationary and publications.
SIZE Millimeters
The B series: The B series is about half way between two A sizes. It is intended as an alternative to the
A series, used primarily for posters and wall charts.
SIZE Millimeter
B0 1000 x 1414
B1 707 x 1000
B2 500 x 707
B3 353 x 500
B4 250 X 353
B5 176 x 250
B6 125 x 176
B7 88 x 125
B8 62 x 88
B9 44 x 44
B10 31 x 44
The C series: The C series is used for folders, post cards and envelopes. C series envelope is suitable to
insert A series sizes.
SIZE Millimeter
C0 917 x 1297
C1 648 x 917
C2 458 x 648
C3 324 x 458
C4 229 x 324
C5 162 x 229
C6 114 x 162
C7 81 x 114
C8 57 x 81
RA Series Formats
RA0 860 x 1220
RA1 610 x 860
RA2 430 x 610
RA3 305 x 430
RA4 215 x 305
Envelopes
DL 110 x 220
C6 114 x 162
C5 162 x 229
C4 229 x 458
C3 324 x 458
ISO Brightness
The brightness of paper and board measured at a wavelength of 457 nanometers under standard
conditions.
Ivory Board
High-quality board made in white or colors with a bright, clear appearance, particularly used for visiting
cards and similar high-class printed work. Original Ivory Board was and still is made in Holland, although
the grade is made in many countries.
J
Jet to Wire Speed Ratio
Papermakers adjust the jet-to-wire speed ratio to fine-tune the paper structure. The "jet" is the narrow
stream of dilute stock that comes out of the headbox slice opening. The "wire" is the continuous belt of
forming fabric. Often it is possible to improve the uniformity of paper by running jet-to-wire speed ratio as
one. "Rushing the sheet" means that the jet speed is higher than the wire speed. "Dragging the sheet"
means that the wire speed is higher than the jet speed. Especially in the case of dragging, increasing
values of jet-to-wire speed ratio tend to align fibers in the machine direction. For square sheet (paper
which has same strength properties in CD and MD), jet to wire ratio should be kept as close to one as
possible.
Job Lot
Out of specification, defective or discontinued types of paper made in small quantities for special orders
and sometimes sold at lower than regular prices.
Jog
To shake a stack of papers, either on a machine or by hand, so that the edges line up. Finisher jog the
paper to remove any improperly cut sheet. Printers jog the paper to get rid of any dust or particles and to
ensure proper feeding into the press.
Jumbo Roll
A roll of paper, direct from the paper machine, wound on a machine winder spool as distinct from rolls
that have been slit and rewound on cores.
K
Kaolin
White clay used as an additive and filler in paper and coating made up chiefly of minerals of the kaolinite
type.
Kappa Number
A term used to define the degree of delignification. Modified permanganate test value of pulp which has
been corrected to 50 percent consumption of the chemical. Kappa number has the advantage of a linear
relationship with lignin content over a wide range. Kappa Number x 0.15% = % lignin in pulp
Kenaf
An annual agricultural plant, native of India, which has along fiber in the bark that, is suitable for
papermaking.
1 Total Alkali Total of all viable sodium alkali compounds i.e. g/L
(TA) NaOH+Na2S+Na2CO3+Na2SO4+Na2S2O3+Na2SO3 excludes NaCl as
NaO
7 Sulfidity Ratio of Na2S to Active Alkali (AA) or to TTA (Basis of sulfidity should % on
be defined accordingly) NaO
basis
Kraftliner
Paperboard of grammages of 120g and more, generally made from bleached or unbleached sulfate pulp
and used as an outer ply in corrugated board.
L
L
Label
A separate slip or sheet of paper affixed to a surface for identification or description. For fiberboard
boxes, includes: Full Label, Mailing or shipping Label, Spot Label and UPC (Universal Product Code) Label.
Label Paper
Mostly one-side coated papers which must be printable in 4-colour offset and gravure printing. These
papers are usually suitable for varnishing, bronzing and punching and sometimes also feature wet
strength and alkali resistance (See "Wet strength and alkali resistant paper") in order to en-sure the
removal of the labels e.g. in the bottle rinsing machines of breweries
Laid
A finished produced with a dandy roll having closely spaced wires.
Laid Lines
A continuous watermark consisting of very close parallel lines, generally associated with spaced lines
(chain lines) at right angles to these.
Laminated Paper
A paper built up to a desired thickness or a given desired surface by joining together two or more webs or
sheets. The papers thus joined may be alike or different; a totally different material, such as foil, may be
laminated with paper.
Laminated Linerboard
Two or more plies of linerboard adhered to one another for increased structural stability.
Laminator
A machine that adheres multiple plies of paper or fiberboard. May be used to adhere full labels to a
facing, or, for enhanced structural properties, multiple facings, corrugating mediums or sheets of
combined board.
Lapping Machine
A wet machine on which folded wet pulp sheets are produced from screened pulp for storage and/or
shipment.
Laser Printing
Xerographic printing where a modulated laser ray is projected on to a photoconductive cylinder or belt by
a rotating mirror. The laser serves to product the electrostatic latent image, which is developed with
toners.
Latency
The curl and spiral of individual pulp fiber created during refining specially in thermomechanical pulping
process
Latency Chest
A storage chest after the second stage refining in thermo-mechanical pulping process in which pulp is
agitated and stored at a specified temperature for a predetermined time to remove latency.
Layboy
A device at the end of cutter for jogging sheets in to a square pile.
Leachate
Water that has as a component of dissolved matter accumulated as a result of passing through material.
e.g. rain water passing through waste dump.
Lead Dryer or Baby Dryer
A small diameter dryer just after the press section.
Leaf Fibers
Papermaking fibers coming from the leaves of the plant such as hemp, manila, flax, sisal etc.
Ledger Paper
A strong paper usually made for accounting and records. It is similar to Bond paper in its erasure and pen
writing characteristics.
Letter Fold
This common fold, used for mailings and brochures, is much like a letter folded by hand for inserting in an
envelope. The letter fold produces a self-contained unit, easily handled by automated envelope inserters.
For picture of this type and other fold please visit http://www.bradenprint.com/pdf/Folds-IS.pdf
Letter Press
A process of printing in which raised images are coated with ink and pressed directly onto a paper or
paperboard surface
Lick Coating
A light form of mineral coating, achieved by supplying the surface sizing press of the paper making
machine with coating material instead of normal surface sizing solution.
Life Cycle
All stages of a product&rsquos development, from extraction of fuel for power to production, marketing,
use, and disposal.
Lift
A pile of sheets of paper; usually the amount placed under the knife of a cutting or trimming (guillotine)
machine.
Lightfastness
The speed at which a pigment or colored paper fades in sunlight. or
How permanent a color is or how unaffected by light it is.
Light Weight Coating (LWC)
Coating applied at 7-10 g/m2 on one or both sides of the paper.
Light Weight Paper
Papers having a grammage (basis weight) normally less than 40 g/m2.
Lignin
A complex constituent of the wood that cement the cellulose fibers together. Lignin is brown in color.
Lignin is largely responsible for the strength and rigidity of plants, but its presence in paper is believed to
contribute to chemical degradation. To a large extent, lignin can be removed during manufacturing.
For further info
Lignocellulose
Refers to plant materials made up primarily of lignin, cellulose, and hemicellulose.
Like-Sided
Paper that has the same appearance and characteristics on both sides.
Lime Sludge or Sludge
Sludge of calcium carbonate (CaCO3) formed during preparation of white liquor in the chemical recovery
process.
Linen Finish
A finished paper that has an overall embossed pattern on the surface resembling the look and feel of
linen cloth, and one manufactured with engraved embossing rolls.
Liner
A creased fiberboard sheet inserted as a sleeve in a container and covering all side walls. Used to provide
extra stacking strength or cushioning. Also used as a short hand for "linerboard" or facing."
Linerboard
The inner and outer layers of paper that form the wall of a corrugated board.
Lines Per Inch (LPI)
The number of lines in an inch, as found on the screens that create halftones and four-color process
images (for example, "printed 175-line screen"). The more lines per inch, the more detailed the printed
image will be. With the demand for computer-generated imagery, the term "dots per inch" (which refers to
the resolution of the output), is replacing the term "lines per inch."
Lint
Loosely bonded fibers at the paper surface that attached to the plate or blanket of the printing machine.
Litho
A generic term for any printing process in which the image area and the non-image area exist on the same
plate and are separated by a chemical repulsion. Usually oil based offset printing.
Loading
Addition of fillers
Loft Dryer
A heated room in which wet sheet of paper/paperboard are hang on poles. This old method of drying is
known as loft drying or pole drying.
Log
A piece of pulpwood length cut from trees to convenient size for storage, transportation and handing.
Logging
The operation of harvesting trees from woodlands, processing in to barked/unbarked logs or chips.
Long Log
A whole length pulpwood before cutting to shorter log.
Look Through
The appearance of the paper when held up to transmitted light. It discloses whether the formation is even
and uniform or lumpy and ‘wild’. For book publishing papers, a regular, even look through is desirable,
indicating a well made, uniform sheet.
Loose Winding
A paper roll winding defect caused by insufficient sheet tension during winding.
Lumen
The center void portion of a cellulose fiber.
Lump
An incomplete separation of fiber bundling or coming together of fibers and other papermaking materials,
causing raised, hard and localized spots in the sheet.
M
M Weight
The weight of one thousand sheets of paper, any size; or double the ream weight.
M2 Yield/Ton
A measure of the surface area of paper/paperboard which is obtained from a ton of paper.
Machine Chest
Usually the last large chest or tank that contains thick-stock pulp before it is made into paper.
Machine Clothing or Paper Machine Clothing
Fabrics of various types employed on the paper machine to carry the web and perform other functions. It
includes the machine wire, dandy roll cover, press felts and dryer felts etc., which may be composed of
natural or synthetic materials.
Machine Crepe
Crepe paper produced on the paper machine, and not as a secondary option.
Machine Direction
The direction of the web through the paper machine.
Machine Finish
Finished produced on the paper as it leaves either the machine or the calender stack. For increased
printability, or smoothness when used as a liner, etc.
Machine Glazed
Machine glazed. Paper with a glossy finish on one side produced on the paper machine by a Yankee
cylinder.
Machine Speed
The rate at which paper machine runs, expressed as m/min or ft/min.
Machine Width
Width of the paper web in the paper machine.
Manifold Paper
A light weight bond paper used for making carbon or manifold copies or for airmail correspondence.
Manila
A semi-bleached chemical sulfate paper. Not as strong as Kraft, but have better printing qualities.
Manufacturing Order
Also known as making order. A quantity of paper manufactured to custom specifications, such as a
special weight, color, or size not available as a standard stocking item.
Market Pulp
Pulp which is made to be used elsewhere for the production of paper. Usually dried to reduce freight
costs but may be "wet lap" ( 50% water).
Marbling
Addition of strongly stained fibers to the stock to give the paper a marbled appearance.
Matte Finish
A dull, clay-coated paper without gloss or luster.
Maximum Trimmed Width
The greatest width of usable paper that is possible to make on a given paper making machine, i.e. the full
width less the necessary trim to give clean edges. There is 3-10% width shrinkage (depending on freeness
of stock) in dryers. It is not possible to specify sizes which, in aggregate, exceed this width.
Mechanical Paper
This paper contains mechanical pulp, thermomechanical pulp (TMP) or chemithermo-mechanical pulp
(CTMP) and also chemical pulp. The shares of chemical and mechanical pulp vary depending on the
application. Highly mechanical papers such as newsprint tend to yellow more rapidly if exposed to light
and oxygen than woodfree papers so that they are mainly used for short-lived products. In printing papers
the mechanical pulp improves opacity.
Mechanical Pulp
Pulp produced by mechanically grinding logs or wood chips. It is used mainly for newsprint and as an
ingredient of base stock for lower grade printing papers.
Medium Density Fiberboard (MDF)
A composite panel made from wood fibers and resin and formed under pressure and heat. MDF has a
smooth surface and good machinability, and is used for furniture, cabinetry and millwork.
Mesh
Count of wires per inch for metal and/or plastic screen used in paper mill.
Metamerism
The tendency of color to appear different under different light sources such as fluorescent or natural
sunlight.
MG Machine
A paper machine incorporating a Yankee or a MG drying cylinder in the drying section to produce MG
paper.
Modified Starch
Papermaking starch that has been processed generally by oxidation, to achieve lower viscosity or
chemical characteristics which are beneficial in use as an additive in papermaking.
Moisture Content
The amount of moisture or water in a sheet of paper, expressed in percent. 6 to 7% is desirable.
Moisture Resistant
Paper Treated with asphalt, wax, plastic, etc. to control penetration of moisture.
Molding Pulp
Pulp, which is used for producing pulp-based or fibrous products by pressing; example products: egg
packages, trays and boxes for fruits and vegetables.
Mordant
Chemical added to pulp to improve the fixation of dyes to the fiber.
Mottle
A random non-uniformity in the visual density, color or gloss of a printed area; also known as orange peel,
back-trap mottle, wet-trap mottle, pigment flocculation, striations, etc.
Mottling Fiber
Heavily dyed fibers added to a different color stock furnish to produce characteristic surface effects.
Mullen
Measurement of the force required, in pounds per square inch, to rupture a sheet of kraft paper. Also
known as bursting strength.
Multi-stage Cooking
Chemical pulping process in which the alkalinity of the cooking liquor is varied by charging the alkali in
several stages.
Multiply Board Machine
A machine in which a number of plies of paper can be combined together in the wet state to produce thick
paperboard..
Multiply Paper Making Process
A paper/board making process in which different layers of fibers are deposited one over the other to form
the sheet. The multiply process is used to make the optimum use of various type of fibers available. It is
also used to make heavy basis weight papers.
N
Native Lignin
The lignin as it exists in the lignocellulosic complex before separation.
Natural Paper
Paper that is not bleached, dyed or tinted. Paper that is the color of natural kraft, a light tan or brown.
Neutral Detergent Fiber (NDF)
Organic matter that is not solubilized after one hour of refluxing in a neutral detergent consisting of
sodium lauryl sulfate and EDTA at pH 7. NDF includes hemicellulose, cellulose, and lignin.
Neutral Paper
Those papers with a pH of 6.5 to 7.5 that indicated freedom from acid and alkali. Such papers will not
cause corrosion when in contact with metals.
Newsprint
A paper manufactured mostly from mechanical pulps specifically for the printing of newspaper.
Nip
"Line of Contact" where two rolls on the paper machine come in contact.
Nitration Pulps
High purity pulps that are reacted with nitric acid to form a class of chemical derivatives called cellulose
nitrates. Cellulose nitrates are used in applications ranging from solvents to smokeless (gunpowder)
propellants.
Non Impact Printing
Printing using lasers, ions, ink jets or heat to transfer images to paper.
Non Wood Fibers
Papermaking fibers derived from plants other than trees such as cotton, hemp, bagasse, jute, bamboo or
straws.
Nonwoven
Fabric-like material made from long fibers, bonded together by chemical, mechanical, heat or solvent
treatment.
O
O
Odd Lot
Off standard paper. Also the term used for side rolls or sheet left after cutting standard size/order.
Off-machine Coating
Coating of paper on a separate coating machine.
Off-machine Creping
A method whereby paper is creped in a separate operation rather than by the paper machine's Yankee
cylinder.
Offset Paper
Also known as book paper. General description of any paper primarily suited for offset printing. Can be
coated or uncoated. Characterized by strength, dimensional stability, lack of curl and freedom from
foreign surface material. Finish can be vellum or smooth.
Offset Printing
Also know as web offset or lithography. Offers highest degree of precision, clarity, and quality.
Old Corrugated Container (OCC)
Brown boxes that have been used for their intended purpose, then collected for recycling.
On Machine Coating
Application of coating to the paper off the paper machine, or as a separate operation to the papermaking.
Optical Brightener
Fluorescent dyes added to paper to enhance the visual brightness; the dye absorbs ultraviolet light and re-
emits it in the visual spectrum.
Opacity
That properties of paper which minimizes the "show-through" of printing from the backside or the next
sheet. The higher the opacity the less likely that the printing on one side will be visible from the other side.
Open End Envelope
An envelope that opens on the short dimension.
Optical Brightness
Optical brighteners or fluorescent dyes are extensively used to make high, bright blue - white papers. They
absorb invisible ultraviolet light and convert to visible light, falling into the blue to violet portion of the
spectrum, which is then reflected back to our eyes.
Optical Whitener
A dye that is added to the fiber stock or applied to the paper surface at the size press to enhance its
brightness.
Orange Peel
A type of sheet surface that looks like orange.
Organosolv Pulping
Pulping method using organic solvent, e.g. organic acid or alcohol, as delignification/cooking chemical.
Out of Square
Paper which is trimmed improperly so the corners are not true 90 degrees. This will result in difficulty
when the presser does not have a good guide edge to work from for accurate register.
Out Turn Sheet
A sheet of paper, taken during manufacture, serving as a reference for the mill or client.
Oven Dry Moisture Content
The percentage loss in weight of a paper specimen when dried to constant weight in an oven maintained
at the temperature of 105 +/- 2 C.
Oxygen Bleaching
A process in which pulp is initially treated with oxygen followed by 4-5 bleaching stages.
Oxygen Delignification
A process in which oxygen gas and sodium hydroxide are used to remove lignin from brown stock.
Ozone (O3)
A highly reactive gas with molecules made up of three oxygen atoms.
Ozone Bleaching
A process that uses ozone to whiten cellulose fibers following the Kraft pulping and oxygen
delignification processing.
P
Packaging Paper
A paper or paperboard used for wrapping or packing good.
Pallet
A platform with a slatted bottom, used to hold and ship cartons of paper stacked on top of each other.
A standard amount of paper that fits on a wooden pallet. In cut-size sheets, a pallet equals 40 cartons.
Paper
A homogeneous sheet formed by irregularly intervening cellulose fibers.
Paperboard
A heavy weight, thick, rigid and single or multi-layer sheet. What differentiates paperboard from paper is
the weight of the sheet. If paperboard is very heavy it is called Board. Paper heavier than 150 gram per
meter square are normally called Paperboard and paperboard heavier than 500 gram per meter square
are called board.
Papermaking
Invented in China by T'sai Lun some 2,000 years ago, papermaking still follows the same basic
procedures. Today wood chips are cooked with chemicals to release cellulose fibers and dissolve lignin,
then washed to remove impurities. Most printing papers are then bleached to lighten the color of the pulp.
Pulp is mechanically and chemically treated to impart certain desired characteristics such as strength,
smoothness and sizing. Large quantity of water is added to uniformly distribution of fibers and additives.
The resulting slurry, which is 99 to 99.5% water, is cascaded onto the continuously moving forming fabric
of the Fourdrinier paper machine. Side-to-side shaking distributes the slurry, forming a tangled web of
fiber as the water drains off. A wire mesh roll called a dandy roll, moves over the surface to modulate the
turbulence and smooth the topside of the paper. A felt blanket absorbs more water from the paper and
sends the sheet on through a channel of hot metal drums that dry and press the paper at the same time
to give it a more even-sided finish. At this point the paper is fully dry and ready for off-machine processes
such as coating, embossed finishes and supercalendering.
Paper Cut
The excruciating, often unforeseeable, and usually invisible-to-the-naked-eye cut received when skin slides
along the edge of a piece of paper at just the wrong angle.
Paper-ink Affinity
The tendency for paper and ink to attract and stay attracted to each other. This keeps the ink on the paper
and off the reader's hands or the next sheet. An incompatibility between ink and paper can cause printing
problems.
Paper Surface Efficiency (printing)
Measure of the printability of a sheet of paper which is dependent upon the amount of ink the paper
absorbs, the smoothness of its surface, and the evenness of its caliper.
Papeterie
A paper used for greeting cards, stationery, etc…which is distinctive from regular stock in that special
watermarks and embossing may be used.
Papyrus
The Egyptians used this aquatic plant to create a writing sheet by peeling apart the plant's tissue-thin
layers and stacking them in overlapping, crosshatched pieces to form a sheet. Despite giving us the word
"paper," papyrus is not a true paper. To view a picture of papyrus plant click here.
Parchment
Animal skins or linings stretched and prepared as writing/painting surfaces. Produces a smooth, buttery
surface.
Parchmentization
Method of treating a paper sheet with sulfuric acid to make it greaseproof.
Parenchyma
Method of treating a paper sheet with sulfuric acid to make it greaseproof.
Particulate
Airborne solid impurities such as those present in gaseous emissions (sodium sulfate, lime, calcium
carbonate, soot).
Peel Strength
The amount of normal force required to delaminate a multiply paper. Strength measured by TAPPI useful
method UM808 or other similar methods.
Permeability
Degree to which a fluid (gas or liquid) permeates or penetrate a porous substance such as paper or fabric.
Perfecting Press
A printing press that simultaneously prints both sides of a sheet of paper as it passes through the press.
On other presses, printing both sides means running the sheet through the press to print one side,
allowing the ink to dry, turning the paper over, and then running the sheet through the press again to print
the other side.
Permanent Paper
A paper that can resist large chemical and physical changes over and extended time (several hundred
years). This paper is generally acid-free with alkaline reserve and a reasonably high initial strength.
Permanence
The degree to which paper resists deterioration over time. There is an international norm which applies to
woodfree papers. The ISO 9706 international norm defines the conditions for producing "permanent"
papers. A paper which fulfils these criteria can be stocked for many years under archival conditions
(temperate medium and protected from light).
Furthermore there is also the German DIN 6738 norm which can be applied to all papers.
Under the DIN 6738 norm, longevity is classified under the following categories :
CL 24-85 : these papers can be described as ageing-resistant,
CL 12-80 : the lifespan of these papers is of several centuries,
CL 6-70 : the lifespan of these papers is of at least 100 years,
CL 6-40 : the lifespan of these papers is of at least 50 years.
However in the German introduction to the ISO 9706 norm, there is a clear restriction concerning the DIN
6738 norm : "The task of archives, libraries, museums and other collections is to conserve documents on
a long lasting basis". That is why printers and editors should take care to respect the requirements of the
ISO 9706 norm. DIN 6738 is valid for books which will predictably be destroyed after use.
Permanganate Number (K Number)
Chemical test performed on pulp to determine the degree of delignification.
Permeability
Degree to which a fluid (gas or liquid) permeates or penetrate a porous substance such as paper or fabric.
Pernicious Contraries
Any material present in waste paper that is difficult to see or detect and which might be detrimental to the
paper being manufactured from the wastepaper or which might either damage paper making equipment
or render repulping difficult
Peroxide Bleaching or Hydrogen Peroxide Bleaching
Method of bleaching pulp with hydrogen peroxide (H2O2) to remove lignin; reduces or avoids the need for
chlorine dioxide in final bleaching.
pH (Hydrogen Ion Concentration)
A measure of the acidity (or alkalinity) of a solution. Range from 0-14 with 7 being neutral, less than 7
being acid; higher than 7 being alkaline.
Photodegradable
A material which undergoes destruction of its chemical structure when exposed to light. Typically, the
materials become brittle with time and fragment into small pieces or powder.
Photographic Paper
The base paper used for the production of photographic papers is a dimensionally stable, chemically
neutral chemical pulp paper with wet strength properties, that must be free from contaminants. Today
papers are coated on both sides with a thin polyethylene film. The cooking prevents chemicals and water
entering the paper during development. This also permits shorter rinsing and drying cycles.
Pick Out
A problem on press caused by unevenly sealed paper, or paper with low bonding strength. The ink "picks"
off weak areas of the paper, lifting coating from a coated stock or lifting fibers from an uncoated stock,
and transferring them to the printing blanket.
These fibers will eventually be transferred back onto the sheets being printed, causing inking and
surface inconsistencies.
Pick Resistance
The ability of paper fibers to hold together during the printing process.
Pick Up Roll
Roll, which lifts the wet paper or paperboard off the wire to transfer to press.
Picking (Papermaking)
To transfer the wet sheet from wire part to press part. If the sheet moves unsupported is called "poor man
pick up". If a solid/suction roll is used to lick/pick the sheet, it is referred as closed transfer.
Picking (Printing)
The problem of ink picking off paper fibers during printing. This may be an indication of a paper with low
bonding strength or the use of an ink with too much tack for the paper it is printed on.
Pigment
An ingredient added to pulp to increase the brightness and opacity of white paper or dye the pulp to
create a colored sheet. Pigments have very high lightfastness and bleedfastness.
Pigmentizing
Coating of paper with a chemical agent (pigment) to reduce surface porosity and increase opacity.
Pin Holes
Imperfections in paper which appear as minute holes upon looking through the sheet. They originate from
foreign particles, which are pressed through the sheet.
Piping
Defect in reels, consisting of ridges running around the circumference, due to moisture take-up by the
surface layers or uneven binding or hard and soft spots.
Pitch
Resinous material present in wood (mainly softwood) that carry over into the pulping and papermaking
system to form insoluble deposits.
Polymer
Organic chemical compounds consisting of repeating structural units. Cellulose is a polymer.
Ply
The separate webs, which make up the sheet formed on a multi-cylinder machine. Each cylinder adds one
web or ply, which is pressed to the other, the plies adhering firmly upon drying.
Plybond
Internal bond strength, measure of the resistance of a sheet of paper to delaminate or blister, due to
stresses created during printing and drying.
Point
A unit of paper or paperboard thickness measuring one-thousandth of an inch.
Polymer
A chemical term for several classes of organic or carbon containing chemicals where a monomer or
single chemical molecule is connected to itself in repeating units to form a chemical "chain." An example
of a polymer is cellulose, a repeating chain of glucose (sugar). Other examples are polyesters, nylons,
viscose, lyocell, polyolefins and polystyrenes.
Pop Test
A slang term for Mullen or bursting strength.
Porosity
The property of paper that allows the permeation of air, an important factor in ink penetration.
Postcard Board
Postcard board is either slightly mechanical or woodfree and calendered.
Post-Consumer Waste Paper
Waste paper materials recovered after being used by consumers.
Poster Paper
Poster paper is a highly mechanical, highly filled, mostly coloured paper that has been made weather
resistant by sizing.
Precision Sheeting
Converting rolls of paper into finished sheet sizes in a single operation.
Pre-Consumer Waste Paper
Paper recovered after the papermaking process, but before used by a consumer.
Press
A combination of two or more rolls used to press out water from wet paper web. Following are some of
the types of the press.
1. Plain Press or Solid Press
This is the simplest and the oldest type of press which is now a days rarely used except on very slow
speed machine. The solid press consist of two solid rolls covered with rubber and or granite. The top roll
is somewhat offset for the squeezed out water to flow by gravity.
2. Suction Press
In this type of press, one roll is drilled and shell of the drilled roll rotates over a suction box. The squeezed
water is sucked out through the felt.
3. Grooved Press
In this type of press, one roll is grooved. The squeezed water is hold in the groves and removed by
doctoring or sucking out on the return run of the roll.
4. Smoothing Press
A plain roll press just before the dryer section start, used to smoothen the paper surface.
Press Part or Press Section
The section of the paper machine which contains press (es). It is usually located between wire part and
dryer part.
Pressure Sensitive Coated Paper
Paper coated with a self-adhesive material which in dry form (solvent free) is permanently tacky at room
temperature. A bond with the receiving surface may be formed by the application of pressure (e.g. by the
finger or hand). A permanent adhesive is characterized by relatively high ultimate adhesion and a
removable adhesive by low ultimate adhesion. Until the time of application, the adhesive surface should
be covered by a suitable release coated paper.
Pressure Sensitive Tape
Kraft tape, coated on one side with a pressure-sensitive material and on the second side with a release
agent. Requires only brief pressure at room temperature to use. Some pressure sensitive tapes are
supplied with a release backing of paper that is removed at the time of use.
Pressurized Groundwood Pulp (PGW)
Mechanical pulp produced by treating logs with steam before defibration against a grindstone under
externally applied pressure.
Primary Packages
The package which contain the actual product. E.g. beer bottle or ice cream tub etc.
Printability
The overall performance of the paper on press.
Printing
The transfer of ink onto paper or other materials to reproduce words and images.
Processed Chlorine Free (PCF)
Recycled pulp produced without elemental chlorine but using
chlorine derivatives.
Pulp
A suspension of cellulose fibers in water.
Pulp
Pulp Board
Also known as Printers’ Board, this grade is made from a single web of pulp on a paper making machine,
and is produced in various substances. Used for index cards and other general products, these boards
may be white or colored.
Pulper
Unit for defibrating (slushing) pulps and paper machine broke, usually at the wet end of the paper
machine.
Pulping
Pulping is the process by which plant material (wood, grass, straw etc.) is reduced to a fibrous mass. It is
achieved by rupturing bonds within plant structure. It can be accomplished mechanically, thermally,
chemically or some combinations of these treatments. Following table provides pulp yield and relative
strength achieved using various pulping methods.
Classification Process Yield of Relative Relative
Pulp Strength (SW) Strength (HW)
* Process not used for Softwood (SW). ** Process not used for Hardwood (HW).
Puncture Resistance
The puncture resistance of combined board indicates the ability of the finished container to withstand
external and internal point pressure forces and to protect the product during rough handling.
Q
Queen Roll
The second roll from the bottom in a calender stack, usually smaller in diameter than the king roll, but
larger than the rest of the rolls above it.
Quired
A ream of paper in which the sheets are folded in half instead of flat.
R
Rag
The term “rag” is often used interchangeably with “cotton fiber content” and harkens to a period of time
when paper was actually made using cotton rags which were cleaned and then broken down into fibers
which were then used to manufacture paper. In a sense it could be stated that the fine paper business has
been engaged in recycling materials for production since its very beginning. Today paper is no longer
made from rags and the term “rag” is falling in disfavored by the industry in lieu of the phrase “cotton fiber
content”.
Rag Paper
Today rag paper is mostly made from vegetable fibers consisting of cellulose, such as cotton, linen, hemp
and ramie. Rags are the most precious raw material for the papermaker. Rag papers and rag-containing
papers with admixtures of chemical pulp are used for banknotes, deeds, documents, books of account,
maps and copperplate engravings and as elegant writing papers. They are also used for special technical
applications.
Rag Pulp
Papermaking pulp made from textile waste, cotton, hemp or flax.
Ragger Rope
A rope used to remove contraries from the pulper.
Rattle
That combination of properties such as stiffness, density etc. which is responsible for noise when the
sheet is shaken or flexed.
Ream
500 Sheets of paper.
Reclaimed Fibers
Recovered fiber in a pure or usable form obtained from refuse matter.
Recovered Paper
Paper recovered for recycling into new paper products. Recovered paper can be collected from industrial
sources (scraps, transport packaging, unsold newspapers...) or from household collections (old
newspapers and magazines, household packaging).
Recovered Paper Grades
Recovered paper sorted by types in order to be recycled by paper mills. Specific grades are used by paper
mills, in order to produce different types of paper and boards.
Recovery Boiler
Boiler used to burn black liquor from chemical pulping for recovery of inorganic chemicals as well as for
energy production.
Reel
A continuous sheet of paper wound on a core.
Refiner
An equipment used to give mechanical treatment to the fibers.
Water 1.33
Cellulose 1.53
Starch 1.53
Clay 1.55
Talc 1.57
Registration
Putting two or more images together so that they are exactly aligned and the resulting image is sharp.
Reinforcement
Method for strengthening paper with an insert or surface layer of glass or other synthetic fiber or metal .
Reinforcement Pulp
Softwood chemical pulp added to give paper greater strength and to improve runnability on the paper
machine or printing press.
Reject
Material removed and discarded during the cleaning and screening of pulp/stock.
Release Paper
Release paper is used to prevent the sticking of glue, paste or other adhesive substances. Coating paper
with silicone yields papers with a surface that prevents adhesion of most substances. Application: cover
material for self-adhesive papers or films, e.g. in label production.
Relief
A method for printing ink on paper, using type or images that rise above the surface of the printing plate.
Ink sits on top of these raised surfaces, and as the paper is pressed onto them it picks up ink. Letterpress,
flexography, and rubber stamps all use relief plates. In letterpress, intense pressure can cause images to
be slightly debossed or depressed below the surface of the paper.
Residual Fibers
Fibers derived from sawmills scraps, plywood plants and other timber management activities.
Resilience
A paper's ability to return to its original form after being stretched, bent or compressed during the printing
and bindery process.
Retention
The amount of filler or other material which remain in the finished paper expressed as a percentage that
added to the furnish before sheet formation. Retention can occur by various mechanisms. The simplest
of these is mechanical sieving by the forming fabric. Once a fiber mat begins to form, the mat itself
usually can act as a much more effective and finer sieve than the forming fabric. But even then, particles
less than about 10 micrometers in size are not effectively retained by sieving. Rather, retention of fine
particles requires the action of colloidal forces, including polymeric bridging or a charged patch
mechanism (by mitchell at tf). Retention aid chemicals can be effective either by attaching fine particles
to fiber fines or fibers or by agglomerating them so that they can be sieved more effectively.
Retention Aid
Chemical additives, especially high molecular weight copolymers of acrylamide, designed to increase the
retention efficiency of fine materials during paper formation.
Rewinder
Equipment which slits and rewinds paper webs into smaller rolls.
Rice Paper
A common misnomer applied to lightweight Oriental papers. Rice alone cannot produce a sheet of paper.
Rice or wheat straw is used occasionally mixed with other fibers in paper making. The name may be
derived from the rice size (starch) once used in Japanese papermaking
Ridges
Roll defect where there are raised bands or rings of material around the circumference of the roll.
Right Handed or Left Handed Paper Machine
If the paper web runs left to right as one faces the machine on the front side, it is right handed machne. f
not, it is left handed.
Ring Crush Test (RCT)
A test method for measuring the edgewise crush resistance by forming the paper into a cylinder and
applying a crushing force to the edge. (TAPPI T818)
Rising Film Evaporator
A type of tubular heat exchanger used for concentrating a solution consisting of a non-volatile solute and
a volatile solvent; solution flows upward on the heat exchange surface; vaporization ' of the volatile
solvent reduces the density of the mixture and causes the vapour-liquid mixture to rise; commonly used in
pulp mills but less common in new installations.
Rod Coater
In rod coater, the rod is the metering device, which controls how much wet coating is allowed to leave the
coating station. Typically thirty times more will be applied compared to the actual target coat weight.
Roe Number
Measure of the amount of chlorine required for bleaching pulp.
Roll Coating
A process in which the coating is applied by roll and subsequently smoothed by means of reverse rolls
contacting the freshly coated surface.
Roofing Paper
Board that is impregnated with tar, bitumen and/or natural asphalt.
Rosin
Rosin, a natural resin from pine trees in combination with alum, is used for internal sizing of paper in
acidic paper making. The chemical formula of rosin is C19H29COOH.
Rosin Size
Partially or completely saponified (neutralized) rosin. The chemical formula of rosin is C19H29CONa.
Rotogravure
The opposite of letterpress printing in that the design areas are recessed into the plate instead of being a
relief. It is web-fed and prints thin, quick drying ink to produce multiple colors. Used in corrugated
packaging.
Rough
Heavily textured surfaces produced by minimal pressing after sheet formation.
Rough Finish
Paper having an exceptionally rough or coarse textured surface.
Runnability
The ease with which a paper moves through a printing press or converting machine. This is primarily
determined by the paper's strength, tear resistance, dimensional stability, bonding strength and water
resistance
S
Sack
The term is used interchangeably with the word "bag" applied to a non-rigid container made from paper or
other flexible material.
Safety Paper
Papers with a special protection against abusive imitation. The safeguards used during the production of
the paper - some of them chemicals are secret.
Salt Cake
Or sodium sulfate added to the black liquor to compensate for the soda loss.
Sanitary Papers
The group of sanitary papers includes cellulose wadding, tissue and crepe paper, made from waste paper
and/or chemical pulp - also with admixtures of mechanical pulp. As a consequence of the importance of
tissue today, this name is now used internationally as a collective term for sanitary papers. These grades
are used to make toilet paper and numerous other sanitary products such as handkerchiefs, kitchen
wipes, towels and cosmetic tissues.
Sanitary Tissue Paper
Tissue is a sanitary paper made from chemical or waste paper pulp, sometimes with the admixture of
mechanical pulp. It has a closed structure and is only slightly creped. It is so thin that it is hardly used in a
single layer. Depending on the requirements the number of layers is multiplied. Creping is made at a
dryness content of more than 90 %. The dry creping (unlike with sanitary crepe papers) and the low
grammage of a single tissue layer result in a high softness of the tissue products. For consumer products
it is normally combined in two or more layers. The flexible and highly absorbent product [is mainly
produced from chemical pulp and/or DIP - sometimes also with admixture of groundwood pulp] can also
be provided with wet strength. Applications: facial tissues, paper handkerchiefs, napkins, kitchen rolls,
paper towels, toilet paper.
Sap Wood
The fluid part of the tree that moves up from the roots through the outer portion of the trunk and branches
and contributes to its growth.
Satin Finish
A smooth, satin-like, semi-glossy finish of paper or Bristol.
Save-All
Equipment used to reclaim fibers from white water.
Saw Dust
Fine wood particles created when sawing wood; used as biofuel, pulping raw material, panel board
production, animal litter etc.
Scaling
To impress or indent a mark with a string or rule in the paper to make folding easier.
Score
To impress or indent a mark with a string or rule in the paper to make folding easier.
Scott Bond
An internal bond test that measures the force needed to separate fibers within a single ply by TAPPI
method.
Screen
Device used to remove large solids particles such as fiber bundles and flakes from stock. In good old
days screen used to be open type and could deal with thin stock only. Modern screen are closed
(pressurized) and can handle low, medium and even high consistency stock. Perforation in screen basket
can be circular, counter shrink or slotted. The screen used just before headbox not only remove large
particles but also align fibers in the direction of stock flow.
Scuff Resistance
Linerboard's ability to resist abrasion in the shipping environment may affect external appearance.
Seam
The means of joining the two ends of the fabric together.
Secondary Fibers
Fibers recovered from waste paper and utilized in making paper or paperboard.
Secondary Packages
These package the primary package which contain the actual product. E.g. water bottles shrinkwrapped.
Security paper
Paper which includes identification features such as metallic strips and watermarks to assist in detecting
fraud and to prevent counterfeiting.
Self Adhesive paper
Used essentially for labeling purposes, this grade has a self-adhesive coating on one side and a surface
suitable for printing on the other. The adhesive is protected by a laminate which enables the sheet to be
fed through printers or printing machines, the laminate subsequently being stripped when the label is
applied
Semi-Alkaline Pulp (SAP)
Sulfite pulp cooked at slightly alkaline pH (normal sulfite pulp is cooked at acid pH). SAP is superior in
strength to normal sulfite pulp. Used mainly in printing papers.
Semi-Bleached Pulp
Pulp bleached to a brightness somewhere between that of unbleached and fully bleached pulp.
Semi-chemical Pulp
Pulp produced by chemical treatment followed by mechanical treatment.
Sett
A number of units or bales picked up at the same time by crane or truck.
Shade
The color depth and hue in comparison to papers that are the same color; also used to describe the color
achieved by adding dye to pulp slurry. There is a wide shade variety in white papers, as well as in colored
papers.
Shadow Mark
A defect in paper appearance which looks like the drilling pattern in a suction roll. It is due to opacity
effects caused by areas of vacuum and pressure as the wet web passes over a suction roll.
Shake
The device to shake the wire at the breast roll end from side to side.
Shaving
Trim from paper converting and bindery operations.
Sheffield Porosity
A test used to measure the smoothness of paper by measuring the rate of air flow over the surface of the
sheet. The lower the number, the smoother the sheet.
Sheeter or Cutter
Machine for cutting the paper web into sheets.
Signatures
A section of book obtained by folding a single sheet of printing paper.
Shives
Small bundles of fibers that have not been separated completely during pulping.
Show Through
The degree to which a printed film is visible through paper due to the low opacity of the paper.
The undesirable condition in which the printing on the reverse side of a sheet can be seen through the
sheet under normal lighting conditions. The more opaque a sheet, the less the show-through.
Showers
Water jets or sprays used throughout the pulp and paper mills to wash wire mesh screen, forming wires,
press felts, pulp mat, to dilute pulp etc.
High Pressure Showers A shower consisting of numerous needle jet nozzles along its length at a
pressure of up to 300 psi.
Lubrication Showers A shower consisting of fan nozzles along its length to provide full coverage of the
felts surface with water. This lubricates the felt as it passes over the suction boxes.
Oscillation Showers The movement from side to side of the shower bar to ensure full coverage of the
felts surface by the water jets.
Side Run
(1) A narrow reel removed from a web during processing, the width of which is less than the size
ordered, but is large enough to permit its use for purposes other than re-pulping.
(2) An additional part of an order placed in order to better utilize the maximum trimmed machine width
of the making machine.
Size Press
Section of paper machine where surface treatments are applied to the sheet of paper to give it special
qualities. Normally comprised of a pair of rolls towards the end of the dryer train between which the dry or
partially dry web is passed, and into the nip of which a liquid, usually starch, is applied to impart strength
to the sheet. Sometimes a chemical may be added to produce a water-resistant sheet
Sized Paper
Sizing reduces the water absorbency of the paper and thus creates the condition for the writability with
ink. Sized paper is also used for many other purposes (printing, coating, gluing, etc.), and the sizing
agents must fulfill a wide range of tasks. For instance, they control the water absorbency and increase the
ability to retain water and ink (pick resistance).
Sizing
The treatment of paper which gives it resistance to the penetration of liquids (particularly water) or
vapors. Sizing improves ink holdout.
Slabbed
Type of paper stock normally generated by cutting rolls.
Slice
Outlet from the head box through which the pulp suspension is fed into the forming section.
Slide Resistance
The ability of containers to resist sliding in unit loads can be predicted for the coefficient of friction of the
combined board. A low coefficient demonstrates containers slipping from the load.
Slimes
Fungus or other bacteriological growth. If not controlled in papermaking system, may cause process and
quality problems.
Slime Holes
A hole in paper, characterized by brownish translucent material around the edges. Caused by a lump of
slime which has formed in stock system from the growth microorganisms, then becoming detached and
flowing onto the paper machine wire with the fiber to form a non-fibrous area.
Slitter
Rotary knife used to slit or trim a paper web into specified width.
Slitting
Dividing a web of paper in the lengthwise direction into two or more narrower webs.
Slowness
Measure of pulp drainage. Has an inverse relationship to freeness.
Sludge
The waste material left over after pulping and deinking. Although some sludge is produced in the virgin
papermaking process, far more is produced in the deinking (recycling) process. Recycling breaks
recovered paper down into fibers, which are sent to the paper machine for new production, and other
materials, which drop into the sludge. These "other materials" include clay coatings, fillers from the
previous paper, paper clips and staples, fibers too short to be made into paper, ink if it wasn't skimmed off
in the deinking process, and any "junk" that crept into the wastepaper bales.
Smelt
Inorganic chemicals obtained in molten form from the recovery furnace.
Smooth Finish
A highly calendered or machine-finished sheet.
Smoothness
The surface uniformity of paper. Sheets that are flat and even provide better ink dot formation and
sharper images.
Soda Pulping
An alkaline pulping process that uses a simple, sulfur- free sodium hydroxide as cooking liquor.
Soft Cook
Over-cooked pulp.
Soft Nip Calendar
A machine device consisting of two or more pairs of steel and composition rolls; it is designed to achieve
much of the quality of a Supercalender, with much of the production advantage of being on machine, but
without the severe operating difficulties of an on-machine Supercalender.
Softwood
Woods obtained from coniferous trees. Generally grown in cold climates. Softwood grows slower than
hardwood but have longer fibers compared to hardwood.
Solid Fiberboard
Collective term for all solid board grades.
Specialty Paper
The group of specialty papers comprises numerous paper grades, each characterized by particular
properties. These properties often require special raw materials.
Specialty Pulp
Chemical pulps used for purposes other than ordinary papermaking (e.g. in textile production)
Specific Energy (Refining)
Energy applied per unit weight on oven dry basis (KWH/MT) during refining.
Specific Surface (Fiber)
Fiber surface area per unit weight (OD basis)
Specific Surface Load (Refining)
Specific edge load divided by refiner bar width factor (Watt-Sec/m2)
Speck
A small defect of foreign substance with contrasting appearance to the surrounding paper.
Spent Liquor
Liquor recovered from cooked pulp.
Splice
Formed by overlapping webs and joining with a strip of double-faced adhesive tape. Used for lighter-
weight grades of paper.
Spread Coating
A method of coating a web of paper by means of a vertical plate restraining a pond of viscous coating
material, for example resins, plastics or adhesives, which is drawn through an adjustable gap between the
plate and the paper by the forward movement of the web over a horizontal support
Stampers
The wooden hammers used in a watermill to pulp rags in order to separate the fibers.
Standard Test Conditions
Atmospheric conditions of temperature and humidity in which laboratories agree to conduct tests,
eliminating those variables in comparing results.
Starch
A natural product from corn, potatoes, tapioca, etc., and used for dry strength. Cationic starch is added at
the paper machine wet end.
Starch is a free flowing white powder. Typically, starch used in the paper industry is extracted from maize
kernels, wheat or potatoes; in rare cases, tapioca or rice can be the source. Starches from the different
plants each have a characteristic granule size and shape.
Amphoteric starch is a modified starch that contains positively and negatively charged substituent
groups. It is used as wet-end additives, surface sizing agent and coating agent in the paper mill industries
Potato starch is often referred to as farina, and maize starch is sometimes called corn. Native starch is
sometimes called pearl starch.
Sulfate Pulping
Alkaline process of cooking pulp.
Sulfite Pulping
Acid process of cooking pulp
Supercalender
A stack of alternating steel and fiber-covered rolls at the end of the paper machine which is used to
increase a sheet's gloss and smoothness.
Supercalendering
Treatment of paper on an off-machine supercalender to improve smoothness and gloss.
Surface-Sized
Paper that has been treated with starch or other sizing material at the size press of the paper machine.
This term is used interchangeably with the term "tub-sized", although tub-size more properly refers to
surface sizing applied as a separate operation where the paper is immersed in a tub of sizing (starch or
glue), after which it passes between squeeze rolls and is air dried.
Surface Roughness
For coated boards, Parker Print Surf (PPS) roughness tester is used where the test result is expressed as
an average of the surface profiles in micrometers (mm) low results show smooth surface while high
results indicate poor surface.
For coated board, Bendtsen method readings given as total leakage of air in ml/min. Smoother surface
has lower readings
Surface Smoothness
The smoothness of the linerboard surface may affect printing quality because slight depressions may not
receive complete ink coverage. Surface smoothness may also affect the coefficient of friction, gloss and
coating absorption.
Surface Strength Test
The method consists of printing a strip of paper in a print tester at an accelerating rate. The method is
preferable to Wax Pick.
Swelling
An increase in volume of fiber due to the absorption of liquid.
Synthetic Fiber Paper
Papers made from synthetic fibers such as polyamide and polyester, from viscose staple fiber or
sometimes also with fillers. The fibers are mainly held together by binders. The durable synthetic fiber
papers are used for maps and highly important documents such as driving licenses or vehicle registration
books.
T
T4S
Abbreviation indicating that the paper has been guillotine trimmed on all four sides. Literal translation:
trimmed four sides.
Table Roll
The small diameter rolls used to support the wire.
Tack or Stickiness
Tack is a critical property of the ink used in lithography. Because the ink sits on a flat surface, it needs
internal cohesion; in other words, it needs to stick to itself so that it doesn't run all over the plate.
However, too much tack can cause it to pull the paper apart.
When printing two or more ink colors in line, the ink tack and sequence must be adjusted in order for
the inks to adhere to each other as well as to the paper.
Tag Paper
A heavy utility grade of paper used to print tags, such as the store tags on clothing. Tag paper must be
strong and durable, yet have good affinity for printing inks.
Talc
Mineral used in papermaking as a filler and coating pigment.
Tear Index
Tear index = tearing resistance/basis weight.
Tear Resistance
The mean force required to continue the tearing of paper from an initial cut under standardized
conditions.
Tear Strength
A measure of how likely a paper will continue to tear once started. Tear strength will differ with and
against the grain.
Telescoped Roll
Progressive roll edge misalignment, concave on one side, and convex on the other; also called "dished"
roll for the concave side.
Tensile Energy Absorption (TEA)
It is the work done when a paper specimen is stressed to rupture in tension under prescribed conditions
as measured by the integral of tensile strength over the range of tensile strain from 0 to maximum.
Tensile Index
Tensile index = tensile strength (N/m) /basis weight (g/m2).
Tensile Strength
A measure of how likely a paper is to break when pulled at opposite ends. This is very important when
running through high-speed web presses.
Testliner
Mainly produced from waste paper used as even facing for corrugated board or as liner of solid board.
They are often produced as duplex (two-layer) paper. The grammage is higher than 125 gsm.
Text Paper
Text papers are defined as fine, high quality uncoated papers. Typically, they are made in various colors,
with numerous textures and a variety of surface finishes. Text papers are made from high-grade bleached
wood pulp, cotton fibers, or tree-free pulp such as bamboo. Recycled sheets include high quality recycled
waste paper and post-consumer waste pulp, in addition to bleached wood pulp, tree-free pulp or cotton
fibers.
Thermal Airlaid
An airlaid manufacturing using special bicomponent fibers as bond fiber to glue pulp together. The airlaid
is then run through a dry oven to make the product bulkier and softer for use in hygiene or medical
products.
Thermal Paper
Any paper with a heat-sensitive coating on which an image can be produced by the application of heat.
Thermal Transfer Printing
Printing whereby a design image is first printed on heat transfer paper using inks with sublimable
dispersed dyes.
Thermo Mechanical Pulping (TMP)
Mechanical pulp made by steaming wood chips under pressure prior to and during refining, producing a
higher yield and stronger pulp than regular stone groundwood or regular refiner wood pulp.
Thermography or Raised Priting
Also known as "raised printing" or by the trade named unit "Virkotype"; this process is used in conjunction
with a printing unit (letterpress or offset lithography) with slow drying inks. Immediately after printing, the
paper is dusted with a powdered compound and the excess which does not adhere to the wet ink film is
removed. The ink and powder are then fused and swollen above the level of the paper, by elevated
temperature/ heaters. This imparts an embossed or engraved appearance and feel.
Thin Paper
Includes carbonizing, cigarette, bible, air mail and similar papers.
Thinning
A practice in which certain trees are removed from a dense stand to allow the remaining trees adequate
sunlight, nutrients and moisture to grow at an even rate.
Tint
To vary a color by adding white. Also, a very light or delicate variation of a color.
Tissue
A low weights and thin sheet. Normally a paper sheet weighing less than 40 gram per meter square is
called tissue.
At-Home products: Also known as Consumer Products, these are the tissue products you purchase in
the grocery store and convenience store for use in your home and include toilet paper and facial tissue,
napkins and paper towels, and other special sanitary papers.
Away-from-Home products: Also known as Commercial &Industrial Tissue, these are the products that
serve markets such as hospitals, restaurants, businesses, institutions, and janitorial supply firms.
Specialty: These types of tissue papers are often high-end, decorative papers that are glazed, unglazed,
or creped, and include wrapping tissue for gifts and dry cleaning, as well as crepe paper for decorating.
Facial tissue: The class of soft, absorbent papers in the sanitary tissue group. Originally used for
removal of creams, oil, and so on, from the skin, it is now used in large volume for packaged facial
tissue, toilet paper, paper napkins, professional towels, industrial wipes, and for hospital items. Most
facial tissue is made of bleached sulfite or sulfate pulp, sometimes mixed with bleached and
mechanical pulp, on a single-cylinder or Fourdrinier machine. Desirable characteristics are softness,
strength, and freedom from lint.
Titanium Dioxide
An opaque and expensive compound used as a white pigment and opacifier in papermaking. Elemental
titanium is a lustrous, lightweight, white metal with exceptional strength.
Tolerance
Permissible degree of variation from a pre-set standard.
Ton on Tonne
Metric ton or Metric Tonne is equal to 1000 Kgs. or 2240 lbs. English tons are as defined. Long Ton =
2240 lbs is similar to metric ton. Standard English ton is 2200 lbs. Short ton is 2000 lbs.
Top Side
Side of the paper opposite to the wire side.
Total Alkali
NaOH + Na2S + Na2CO3 + 0.5*Na2SO3 all expressed as Na2O in alkaline pulping liquor.
Totally Chlorine Free (TCF)
Totally chlorine free applies to virgin fiber papers that are unbleached or processed with a sequence that
includes no chlorine or chlorine derivatives. (Also see ECF)
Translucency
The ability to transmit light without being transparent.
Translucent Drawing Paper
A paper suitable for drawing office use; sufficiently translucent for an image on it to be reproduced by
processes using transmitted light and for a design to be traced on it from an original placed beneath it.
Such processes include blueprint and diazo.
Transparency
Ability of paper to allow light rays to pass through so that objects behind it can be clearly seen.
Transparent Paper
Extended and particularly careful grinding of high quality fibers (hard chemical pulps, rags) yields a raw
material permitting the production of transparent paper.
Treated Paper
Papers which have functional characteristics added through special treatment. Among the most common
are insect resistant, mold resistant, clay coated, and flame retardant.
Trim
To cut true to exact size, by cutting away the edges of paper in the web or sheet.
Cuttings of paper generated at converting or bindery operation.
Tub Sizing
The operation of surface sizing paper by passing it through a bath of a suitable solution such as gelatin.
Tube Digester
Single or multi-tube continuous digester; used mainly in nonwood pulping and sawdust pulping purposes;
horizontal tubes.
Twin-wire Machine
A papermaking machine with two continuous forming wires, rather than just one. Twin-wires were
designed to create a less two-sided paper than paper manufactured on a Fourdrinier paper machine.
Other techniques for reducing two-sidedness have since been developed, enabling paper
manufacturers to create paper on single-wire machines with little side-to-side variation.
Alum Control pH
Improves Retention
Attach additives on fibers
Part of Rosin-alum sizing
Filler (clay, CaCO3, TiO2 Improve opacity, printing, surface smoothness etc.
etc.)
Wet Strength Resin To impart wet strength to such papers as coffee filter
Wet Lap Machine
Paper machine consisting essentially of a wire covered cylinder rotating in a vat of pulp stock on which a
mat of varying thickness is formed by drainage. These mats are removed either intermittently in thick
sheets called laps, or continuously.
Wet Strength Paper
A chemically treated paper strong enough to withstand tear, rupture or falling apart when saturated with
water.
Wet Tensile Strength
The measure of the force necessary to break a one inch strip if paper after it has been immersed in water.
Wetting Agent
Substance that increases the wettability of a surface for a liquid.
White Liquor
White liquor is the aqueous solution of sodium hydroxide &sodium sulfide used as the cooking liquor in
Kraft pulping.
White Pitch
Deposits on papermaking equipment, a major component of which is latex binder from coated paper or
broke.
White Top Liner
A two-ply sheet comprised of one bleached and one unbleached layer.
White Water
The filtrate from the wet end of the paper machine.
White Water System
Flow circuit for paper machine white water (includes pipes, storage tanks, cleaning equipment, water from
forming section and return feed). Click to see Picture 1 2
Whiteness
Whiteness of pulp and paper is generally indicated by its brightness, which is the reflectance of a
wavelength of blue light. So-called white papers have a definite hue. Most are made with a blue white tint.
Whole Tree Chip
Wood chips produced by chipping whole trees, usually in the forest. Thus the chips contain both bark and
wood. They are frequently produced from the low-quality trees or from tops, limbs, and other logging
residues.
Wicking
The bleeding of ink from the ink jet printing process into unwanted areas of the paper, causing a blurring
effect of the printed character or image.
Winder, Rewinder
Machine for cutting the paper web longitudinally into narrower webs, which are then wound to reels; also
slitter-winder.
Winding
Operation whereby a web of paper or board is wound into one or more reels.
Wire or Machine Wire
The moving "screen" at the wet end of a paper machine where the sheet is formed.
Wire Guide Roll
The small diameter roll used for guiding (keeping on track) the wire. One end of the roll is adjusted to
compensate any misalignment.
Wire Return Roll (s)
The small diameter rolls used at the return run (Couch roll to Breast roll) of the wire.
Wire Mark
On the bottom or wire side of the paper, these are impressed traces of the machine wire.
Wire Side
The side of a sheet next to the wire in manufacturing; opposite from the felt or top side; usually not as
smooth as the felt or topside.
Wire Tension Roll
The small diameter rolls used at the return run (Couch roll to Breast roll) of the wire to adjust the tension
of the wire.
Wood-Free
Pulp furnish without mechanical pulp.
Wood Free Paper
Paper made without mechanical wood pulp.
Wood Pulp
Mechanical or chemical pulp made from wood (cf. Non-wood pulp).
Wove
The Paper having a uniform surface and no discernible marks. Soft, smooth finish, most widely used
writing, printing, book and envelope paper. Relatively low opacity, brightness and bulk.
Wrapper
The materials, consisting usually of paper or paperboard, sometimes with treatment for moisture barrier
properties, which are used to protect the roll or pile form damage.
Wrinkle
Wrinkles are narrow folds in the paper caused by uneven paper tension profile. The wrinkles have a typical
visual appearance, but often very subtle.
Blade Wrinkle: Blade coating defect, an irregular line on the coated surface, essentially in the machine
direction.
Winder Wrinkle: Ridges at an angle to the machine direction, caused by hard sport in the reel.
Writing Paper
Uncoated paper that is suitable for writing with ink on both sides. The writing must neither bleed nor strike
through. Writing paper is always fully sized and also suitable for printing. It can be woodfree or
mechanical, depending on the intended purpose. The admixture of fillers makes it less translucent.
X
Xerography
The printing process used by photocopying machines. Electric charge creates the image on an eloctro-
photographic surface that works as a plate. This surface is cleared after each copy is made, and used
over again for the next copy. For detailed characteristics paper requirement of Xerographic Machine,
please visit Paper Needs of Xerographic Machines (A Summary) by Chuck Green
Xylan
A type of hemi-cellulose in wood. Yellow, water-soluble, gummy polysaccharide found in plant (e.g.
hardwood or cereal straws) cell walls; main structural components are xylose and other pentoses; yields
xylose and other pentoses upon hydrolysis.
Xylanase
Enzyme used for hydrolysis of xylan in pulp bleaching.
Y
Yankee Machine
A type of Fourdrinier paper machine employing a single dryer of large circumference with highly polished
surface.
Yellowing
Or brightness reversion is the discoloration of white paper primarily due to aging.
Yield
Ratio of product output and raw material input, expressed in percentage. Typical yield of some pulps.
Pulp Type Yield %
TMP 94-96
CTMP 85-94
Semi-Chemical 65-90
Z
Z-Direction
The direction perpendicular to the plane of a sheet of paper.
Z-Direction Tensile Strength
The tensile strength measured in Z-direction.
Z-Bleaching Stage
Ozone (O3) Bleaching stage.
Zero (Effluent) Discharge
No effluent discharge from pulp & papermaking plant.
Zeta Potential
Zeta potential is the parameter that determines the electrical interaction between particles, a high value,
positive or negative, prevents flocculation.
Z-Fold
A paper fold represented by back and forth folds into three panels.