Glossary

Acid-free paper - A paper having no acidity and no residual acid-producing chemicals. Acid-free papers may also be slightly alkaline to resist the harmful effects of an acidic environment and provide greater longevity.All of our bleached board is produced with acid pH ~4-5.

Acidity - Degree of acid found in a given paper measured by the pH factor. pH is measured from 0-14, with 7 representing neutral between acid and alkaline. From 0-7 is considered acid as opposed to 7-14 which is alkaline.

Acid paper - Paper using clay as the predominant filler and an acidic rosin-aluminum mixture as the primary internal sizing agent.

Against the grain (cross direction)- Perpendicular to the grain direction. Folding or feeding paper at right angles to the grain direction.

Alkaline paper - Paper using calcium carbonate as the filler and a synthetic material, compatible with the alkaline process, as a sizing agent. This process increases the longevity, bulk brightness, opacity, and printing characteristics of the paper without added cost. 

Allocation - (1) A designated number of tons to be manufactured for a region and/or customer. (2) A reservation of paper/board from inventory to fill a customer order.

Apparent density - Weight per unit volume of a sheet of paper obtained by dividing the basis weight by the caliper.

Ash - The mineral residue left after burning a sample of paper to determine the percentage of filler it contains.

Backing up - Printing the reverse side of a sheet already printed on one side. 

Banding (strapping) - Steel, plastic, fiber or other bands used to secure or protect rolls, sheets, loads, etc. 

Base stock - Paper that will be further processed as in coating or laminating. 

Basis weight - The weight in pounds of a ream  (3000 sq. ft). eg 185lb/3000ft

Binders - Materials which cause coating pigments to bond. 

Black liquor - The residual lignin-containing chemical in the digester after the wood chip has been pulped. 

Blanket - In offset-lithography, a rubber or polymer surfaced sheet clamped around the cylinder of the press to receive ink from the plate, which transfers the image from plate to paper. 

Blanks - Heavyweight paperboard stocks that range from 15 points to 48 points in thickness. Can be coated, uncoated, and in colors. 

Bleaching - Pulp fibers are generally bleached to produce white fibers for papermaking. Other reasons are: to increase the chemical stability and permanence of wood fibers by chemical purification; and to obtain clean, sanitary fibers as required for food packaging papers. 

Bleed - Refers to the printed image extending beyond the trim edge of the sheet. 

Blistering - Separation of the paper’s coating from the body stock which appears in the form of eruptions. Caused when paper in process of manufacturing is dried too quickly. 

Body - Refers to the physical characteristics of inks, such as viscosity and consistency (i.e. An ink with too much body is stiff). 

Bond strength - Cohesiveness of fibers within paper. Paper with good bonding strength will not pick during the printing process. 

Break - Total rupture of a web of paper during the manufacturing of printing process which results in a tear from edge to edge. Breaks in mill rolls are spliced together and marked with flags to call the attention of press operators to potential difficulties. 

Brightness - Light reflecting property of paper in comparison with a reference standard. Paper brightness affects the legibility and contrast of printing. 

Bristol board - A printing substrate usually with a caliper thickness of .006 and up - (90 lb 24” x 36” - 500 sheets and up). Types of bristols include printing, vellum, postcard, tag, and file folder. 

Brittleness - Property of paper causing it to break while bending. 

Bronzing - Printing with a sizing ink, then applying bronze powder onto the wet ink to produce a metallic luster. 

Broke - Machine trim or damaged paper that is returned to a repulping unit within the paper producing mill. 

Bulk - Opposite of appartent density.  A very dense sheet has low bulk whereas a bulky sheet has a low apparent density.

Bursting strength - A measurement of the strength of paper to withhold pressure. 

Butt roll - The end of parent rolls. It is sometimes produced to make-up the difference in trim when minimum trim cannot be achieved.

Calcium carbonate - (CaCo₃ ) A chemical compound used as a filler and as a coating pigment.

Calender dyed - Same as calender colored. Paper or paperboard that has been colored or stained at the calender stack. Color, transferred from the calender rolls to the paper, may be on one or both sides of the sheet. 

Calender rolls - A set or stack of horizontal cast iron rolls at the end of the paper machine. The web of paper is passed between the rolls to increase the smoothness and gloss of the surface. 

Caliper - The thickness of a sheet measured under specific conditions. It is usually expressed in thousandths of an inch (points or mils). Caliper is affected by paper moisture content and the pressure applied to the wet presses and calenders. Caliper is particularly important when printed materials need to be folded, inserted, and mailed using automatic handling equipment. Variations in caliper across the sheet will cause problems such as loose edges, baggy areas and misregister. 

Cellulose (fiber) - The chief component of the cell walls or woody structure of plants; the fibrous material remaining after the non-fibrous components of wood have been removed by pulping and bleaching operations, used in making paper. 

Chuck - Blocks inserted at the end of cores to support rolls of paper on the roll stand. If the core size received is too large, a chuck can be used as an adapter. 

Clay - A fine grained mineral material used as a filler in paper making or as coating pigments. 

Coated paper - Paper with a surface coating imparting a smooth finish. Coated paper finishes have a higher opacity and better ink holdout than uncoated papers. 

Coating (press applied) - An emulsion, varnish or lacquer applied over a printed surface to protect it Corona treatment level - The electric charge on the coating that allows writing on it. 

Coating (paper machine applied) - A combination of pigments, binders and additives applied to the paperboard surface to impart a smooth surface for improving appearance and print quality. 

Cord - Unit of measurement of pulpwood defined as a pile containing 128 cubic feet of wood, stacked eight feet long, four feet wide and four feet high. 

Core - Shaft in center of a roll around which the web of paper is wound. Inside diameter of roll. Cores can be either metal or cardboard, returnable or disposable. They also come in many different inside diameters and wall thickness.

Cross direction (CD) - Direction or dimension at right angle to the flow through a papermaking machine. The direction across the grain. Paper is weaker and more sensitive to changes in relative humidity in the cross direction than the grain direction. 

Crystallization - A condition of a dried ink film which repels another ink printed on top of it. 

Curl - Waviness, roll or curvature sometimes at the edge of the sheet which can occur due to differences in structure or coatings from one side to the other, or to absorption of moisture on an offset press. 

Cut off - Print length in web printing corresponding to the circumference of the plate cylinder.

Cut-size - Refers to business or writing papers that have been cut to dimensions of 8-1/2 x 11 and 8-1/2 x 14 or 11 x 17.

Cylinder board - Paper board made on a cylinder machine.

Cylinder machine - Same as a vat machine.  It is a type of paper machine that makes paper by partially immersing rotating cylinders in vats of pulp stock.  Paper is formed as the cylinder turns and water drains from it.

Dandy roll - (1) A plain roll situated above the wet web of the paper to provide a smoothing action to the top surface of the paper as it passes under the roll. (2) A watermarking dandy roll is a roll of skeletal structure, sheathed in a wire cloth that has designs, letters or figures affixed to it. As the wet paper web passes under the turning watermarking dandy, the designs are impressed into the paper and a permanent watermark is left in the sheet. 

Deckle - Often used interchangeably with trim, referring to the salable width of the web on the paper machine. 

Deckle edge - The untrimmed feather edge of paper formed on the wire where the pulp flows against the deckle straps. 

De-inked paper stock - Essentially, recycled paper. Ink has been removed by mechanical and chemical means to produce clean fibers. 

Delignification - The process of removing lignin from wood to leave only cellulose fibers.

Densitometer - A sensitive photoelectric instrument which measures the density of photographic images or of colors. Used in quality control to accurately determine the consistency of color throughout the run. 

Density - The density of paper is its specific gravity or weight per unit volume. Directly related to the paper’s absorbency, stiffness, opacity, and resiliency. It is calculated from basis weight and caliper. 

Diameter - Measurement of the widest point across the end of the roll. 

Digester - Pressure vessels in which wood chips are cooked to separate fibers from each other and to remove detrimental particles. 

Dimensional stability - Characteristic of paper to retain its dimensions in all directions under the stress of production and adverse changes in humidity or moisture content. 

Dirt - Dirt in paper consists of any imbedded foreign matter or specks which contrast in color to the remainder of the sheet. 

Doctor-blade - (1) Mechanism used during manufacture to clean the surface of the paper (excess pulp and size) while on the paper machine roll. (2) In gravure printing, used to wipe away the excess ink in the non-printing areas of the plate.

Double- coated - A sheet that has been coated twice on the same side. 

Dryers - A series of large cylindrical steam heated rolls that dry the paper webs to the final moisture content. 

Dry-end - The section on the machine where the dryers, cutters, slitters and reels are located. 

Dry finish - Term indicating that paper or paperboard is calendered without use of water. Also, paper with unglazed, rough finish obtained by the dry finish process. 

Dunnage bags - Protective, inflatable bag used in shipping to protect product from transit damage due to shifting and rough handling.

Equivalent weights - System of comparing papers of different basic sheet sizes and basis weights. Example: 90 lb (25-1/2 x 30-1/2 - 500) is equivalent to 100 lb (24 x 36 -500) Tag.

Felt - Woven, endless belt made of wool, cotton, or synthetic materials used to transport the paper web on paper as it progresses through the paper machine. 

Felt side - The side of the sheet not in contact with the forming fabric during the paper manufacturing process. 

Filler - Minerals, such as clay and other white pigments added to the pulp furnish in the beater to increase opacity and smoothness of the paper, improve ink receptivity, and enhance sheet formation.

Finish - Surface contour and characteristics measurable by smoothness, gloss, absorbency, and print quality.

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 rolls in a skid.

Fluorescent paper - Paper that has been manufactured with the addition of fluorescent dyes which give the brilliance that appears brighter when viewed in natural daylight. Brightness measuring numbers are in the mid-90’s. 

Fold endurance - This test measures the amount of times a strip of paper or board can be bent, creased, and folded before rupture. Folding strength is important in many printing applications such as books, maps, pamphlets, and manuals. 

Formation - This property describes the degree of uniformity of the fiber distribution in a sheet of paper. Levelness and smoothness are dependent upon the paper’s uniform formation. Paper that is poorly formed will affect caliper, opacity and strength properties. 

Four-color process - Primary process ink colors - magenta (red), cyan (blue), yellow and black. 

Fourdrinier - Forming section of the paper machine where a pulp slurry is formed into a mat of paper. This section contains the head box where the slurry is forced out onto a moving forming fabric through which water drains. The fabric is supported by rolls and vacum boxes which aid in dewatering the slurry into a fiber mat. 

Free sheet - Paper that contains no groundwood. 

Furnish - The mixture of fiber and other materials blended in stock suspension from which paper or paperboard is made. 

Fuzz - Loose fibers or lint on the surface of uncoated papers.

Genuine watermark - Watermark made on the paper machine, with a dandy roll.

Gloss - Gloss results from the specular refection of light.  Paper gloss can be measured at various angles of illumination.

Grain  Direction- Direction in which most of the fibers lie in a finished sheet of paper. Fibers flow parallel to the direction in which the paper travels on the paper machine during manufacture. 

Grain long - Term used to designate that the grain of the paper is parallel to the longest measurement of a sheet of paper. The fibers are aligned parallel to the length of the sheet. 

Grain short - Perpendicular to grain long. Grain of paper runs at right angles to the longest dimension of the sheet. Fiber alignment parallels the sheet’s shortest dimension. 

Grammage - A term in the metric system for expressing the basis weight of paper grams per square meter.

Green liquor - The intermediate chemicals generated in the kraft recovery system. This liquor contains the regenerated sodium sulphide. 

Grippers - Metal fingers which hold the paper in place when it travels through the sheet fed press. 

Gripper edge - The leading edge of paper as it passes through a printing press.

Groundwood pulp - A mechanically prepared 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 which can cause discoloration and weakening of the paper. 

Guillotine - Device that is used to cut or trim stacks of paper to the desired size. Three types exist - manually operated, electrically powered cutters and automatic spacing cutters.  

Halftone - In printing, a reproduction of an image of varying tone values, attained by printing dots of various size .

Hardwood - Wood from trees having short fibers. These fibers are used in papermaking to obtain good formation, smoothness, opacity and a good print surface. 

Headers - Paper discs applied to the ends of rolls for protection.

Hickeys - In offset printing, spots in the printed sheet caused by extraneous material, such as dirt and paper particles. 

Holdout - Term refers to the ability of a sheet to resist penetration by liquid substances such as ink. 

Hydration - Any process of altering cellulose fibers to increase their ability to absorb water. 

Hygroscopic - Ability to absorb water vapor from the surrounding atmosphere.

Impression - In printing, the pressure of the blanket or plate contacting the paper. 

Integrated mill - A paper mill which manufactures enough pulp to supply its own papermaking needs.

Intermodal - The use of multi-modes of transportation, such as TOFC, to move product to a designated location.

Inter-trim - Two or more orders combined to trim the machine. 

Internal bond 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.

Jordan - A refining machine consisting of a conical rotor and housing between which the fiber slurry is passed. Its effect is to shorten the fibers and improve sheet formation. 

Jumbo roll - Roll size that does not require off-machine rewinding.

Kaolin - White clay mass primarily composed of the clay mineral, kaolinite.  In refined form, it is used as a coating filler, and as an opacifying agent for paper making.  Its important properties are plasticity when wet and hardening when baked or fired.  Kaolin retains its whiteness after firing.

Air Knife coating - Coating applied to a web of paper with the excess coating removed by a thin layer of air.

Kraft process - The predominant method used for converting a wood chip into wood pulp. It produces a strong pulp needed for high-speed paper machines, presses and converting equipment.

Laminated - Paper that is developed by fusing one or more layers of paper together to the desired thickness and quality.

Lignin - One of the major components of wood. This is the “glue” which binds cellulose fibers together to give a tree its rigidity. This material is hydrophobic, or “water-hating”, rendering the fiber too rigid for most papermaking applications. Hence, the need to separate and remove this wood component from cellulose fibers. 

Load on end - Rolls loaded so that end or flat portion of rolls is resting on conveyance floor. 

Load on side (rolling position)- Rolls loaded so that side or rounded portion is resting on conveyance floor.

LTL - Less than truckload.

MICR - Magnetic Ink Character Recognition.  Twelve stylized characters which must be printed using metallic ink.

Machine clothing - Paper machine felts and wire are often referred to as “clothing”. 

Machine coated - Paper coated one or two sides on the papermaking machine. 

Machine direction - Establishes the grain direction which is always parallel with the travel of the paper over the wire.  Also see cross direction.

Machine trim - Refers to the width allowed across the paper machine. Always a min and max allowed depending on basis weight and grade. Each machine has a specific number of cuts/slitters. 

Market pulp - Pulp which is sold on the open market.  Some paper and board manufactures with pulp producing facilities sell all pulp in excess of that which is required for their paper making operations.  Thus, they are paper manufacturers and sellers as well as pulp manufacturers and sellers.

Mechanical pulp - Wood pulp manufactured wholly, or in part, by a mechanical process.

Moisture content - Refers to the amount of moisture found in a sheet of paper. Average amount ranges from 4-7%. This figure varies from sheet to sheet since paper will emit or absorb moisture according to the condition of the surrounding atmosphere. It is affected by both the drying conditions when made and the relative humidity environment in which it is used. The amount of water in a sheet of paper affects basis weight, printability, physical strength, and runnability. Moisture loss is realized in the form of shrinkage which begins at the edges of paper and moves across the grain causing the sheet to tighten, wrinkle and curl. 

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.

Narrow roll - Small width rolls, usually below 17 1/2”, which require off-machine rewinding. Can vary by grade, mill, machine. 

Net weight - The weight after the deduction of tare weight or waste weight. 

Nip - Point where two rolls on the paper machine come in contact. It is the action of the two rollers coming together simultaneously against both sides of the paper that calenders and supercalenders the paper. 

Nominal weight - The basis weight of the paper at which the paper is billed.

Non-integrated mill - Paper mill with no capacity to produce its own pulp.  It must buy market pulp to supply its papermaking needs.  

Off-machine coating - Process of coating paper with a coater not part of the paper machine. It can be in the same or in a separate facility. 

Offset - Refers to paper that is manufactured specifically for use on offset presses; characterized by strength, cleanliness, pick-resistance and relative freedom from curl. 

Opacity - A property of paper which minimizes the show-through from the opposite side . Opacity is greatly influenced by basis weight, brightness, type of fiber and filler.

Out-of-square - Paper that has been trimmed improperly thus causing the corners to be less or more than 90 degrees.  This leads to difficulties in the printing process and often results in misregister of the printed piece.

pH value - Degree of acidity or alkalinity measured on a scale from 0-14 with 7 the neutral point.  Measurement of pH is important to quality control in making paper and pigments and the preparation of the platemaking chemicals.  pH control of press fountain solutions is also essential to assure maximum plate-life and uniform ink-drying.

Pallet - Construction usually made of light wood on which paper or other materials are packed for shipment. They are used to facilitate the movement of paper in storage or transit by means of motorized lift trucks.

Picking - Fibers in the paper which tend to pull away from the surface during the printing process. This occurs when the tack or pull of the ink is greater than the surface strength of the paper. 

Pigment - The solid particles in inks rendering body, color, or opacity. 

Piling - In reference to printing, transfer of mineral pigment from paper to offset blankets - building up of ink on rollers or on the printing surfaces of plates and blankets. 

Pinholes - Tiny holes or imperfections on the surface of the paper caused by the presence of foreign matter on the paper surface during manufacture. 

Point - In reference to paper, equal to one thousandth of an inch in the measure. Utilized when the thickness of paper is considered. 

Porosity - The degree of compactness of the fibers of the paper. It is an indication of the openness of paper, as measured by resistance to the passage of air through the sheet. 

Post-consumer waste - That fraction of the waste stream which has passed through the hands of an end-user. Ex. one-time used paper bags, newspapers, office papers. 

Pre-consumer waste - That fraction of the waste stream which is disposed of during conversion to the end-use product. Ex. envelope clippings, corrugated box plant die clippings, printing press waste.

Pressboard - Manufactured on a wet machine from sulphate pulp, cotton fiber or a combination of both and finished with a high polish.  Thickness ranges from .031 to .250 of an inch.  Principal qualities:  uniform thickness and density, excellent ply adhesion and good forming and molting properties.  Available in a variety of colors.

Press section- Section of the paper machine just after the Fourdrinier. It takes the wet formed pulp mat and squeezes it under high pressure in the nip between two mechanical rolls in order to further remove water. 

Process printing - Printing from two or more halftone plates to produce various colors and shades.

Rag paper - Historically, paper made with rag pulp. Today it is usually referred to as cotton fiber paper. It may be made from cotton cuttings (rags), linters or other waste cotton. End uses are principally high grade bond, ledger and writing , and papers required for permanent record purposes. 

Ream - 3000 square feet.

Recovery boiler - Process in the kraft recovery system which burns spent cooking liquor to regenerate sodium sulphide. Additionally, the dissolved wood components in the black liquor are burned to generate steam and electricity for the rest of the mill. 

Reel - The roll on which the finished paper product is wound at the end of the paper machine. 

Reel sample - Samples taken from a reel of paper for testing.

Refining - This process disrupts the cell wall of the fiber creating fibrils (split ends) in order to improve the inter-fiber bonds in a sheet of paper. 

Remnant rolls - Leftovers from a previous manufacturing run - i.e., overruns, trim rolls. May also be referred to as “surplus”. 

Rewinder - Equipment used to slit a large width roll into a smaller width. It takes reels from the paper machine, unwinds the web, slits it and then rewinds the web onto fiber board cores. This allows the mill to make a multitude of roll widths and diameters to meet specific customer orders. 

Risers - Blocking and bracing used in rail cars/trailers.

Roll- Paper wound around a core or shaft to form a continuous roll or web of paper. Rolls are made by slitting and rewinding a paper machine reel and are available in many widths and diameters. 

Roll hardness tester - Used to determine the relative uniformity of bulk across a web.

Roll set curl - The curve in paper caused by winding around a roll or core. 

Rolls per bundle - Several rolls banded to each other and wrapped as one. Mainly applies to narrow rolls. 

Rosin size - The soap solution obtained by cooking rosin with caustic soda or soda ash. It is added to the pulp furnish in the beater to render the paper or board water resistant. 

Runnability - A paper’s capability of being transported trouble-free from the roll stand or feeder of a printing press or converting machine.  

Scoring - In reference to paper conversion, creasing by mechanical means to facilitate folding while guarding against cracking of paper and board. Scoring is essential when heavyweight papers are to be folded across the grain. 

Secondary fiber - A term used for wastepaper, also referred to as paper stock. 

Self-trim - An order which trims the machine by itself. 

Semi-bleached - Chemical woodpulp that is partially bleached.

Set log - A number of rolls cut simultaneously from the same reel. 

Set-off - Transferring or smearing of ink from freshly-printed sheets of paper to another surface (also called off-set). 

Sheets - A term which may be applied to a single sheet, a grade of paper or description of the paper, i.e. coated, offset, etc. 

Shives - Undercooked, thus incompletely saturated wood particles that are removed from the pulp prior to the manufacture of paper. Sometimes shives will appear in finished paper. 

Show through - Printing that is seen by looking through a sheet of paper that is not adequately opacified. 

Side roll - The same as a butt roll except this is a salable size and usually cut with a specific outlet in mind. 

Size - Any material added or applied to paper to affect its ink or water absorbency. Starch, alginates and glue are used in surface sizing. Sizing agents are added at the size press section of the paper machine, usually located between two drier sections. Transparent white ink can be printed as a size to minimize linting, increase ink hold-out, dry ink previously printed, or overcome chalking.

Size Press - Part of the paper machine, usually located between two drier sections, where sizing agents are added.

Sizing - The property of paper relating to its resistance to penetration of liquids (primarily water).

Skid - A platform upon which a pile of cut paper sheets is stored and/or shipped.

Slice - In reference to a paper making machine, a device that controls the flow of pulp from the headbox of a Fourdrinier.

Slime spots - Imperfections in the paper surface caused by growth of micro-organisms in the water at the wet end of the paper machine. Occasionally they make their way to the wire or paper. Although they are sterilized during the drying process, they may leave undesirable spots in the paper.

Slitting - Cutting printed sheets or webs into smaller sheets or webs. 

Slurry - A water suspension of fibers. Also, the suspension of pigment and adhesive used to coat papers. 

Smoothness - Measure of paper surface irregularities. Sheffield Smoothness is a measure of the formation induced irregularities. Parker Print Surface measure the paper surfaces micro variation in roughness.

Softwood - Wood from trees having long fibers (pine trees). Softwood fibers are used in papermaking to impart strength to a sheet of paper and are also noted for their exceptional absorbency. 

Solid Bleached Sulfate (SBS) - Paperboard comprised of fully bleached virgin kraft pulp (sulfate process) fiber. Bleached refers to the fact that it is bleached to an appealing high brightness. Sulfate refers to the chemical process used in preparing the pulp. 

Spacer strips - Strips of lumber inserted under rolls loaded on end to facilitate their removal with fork trucks. 

Splice - (butted joint) - Formed by trimming the ends of two webs of paper, placing them end-to-end and pasting a strip over and under to make a continuous web without overlapping. Used for heavier weight papers and board. 

Splice - (overlapping) - Formed by overlapping webs and joining with a strip of double-faced adhesive tape. Used for lighter weight grades of paper. 

Stiffness - The ability of paper or paperboard to resist an applied bending force and to support its own weight while being handled. Stiffness is a critical property for paperboard during the printing, converting, and filling processes.

Stock - (1) Paper to be printed or converted (2) A product not made to order and stored in a warehouse or distribution center. 

Strike-through - The penetration of ink through paper. 

Stub roll - Usually refers to a small diameter roll or a roll with only a small amount of paper remaining on the roll. 

Sulfate pulp - Predominant fiber used by the paper industry. It is obtained by cooking wood chips with the chemicals sodium sulfate and sodium hydroxide. The sodium sulfate is converted to sodium sulfide in the process. 

Sulfite pulp - Fiber made by cooking wood chips in a solution of calcium bisulfite and sulfurous acid. This process has waned in popularity due to its harsh impact on pulp strength. 

Supercalender - Alternating rolls of highly polished steel and compressed cotton in a stack. During the process the paper is subjected to the heated steel rolls and “ironed” by the compressed cotton rolls. It imparts a high gloss finish to some paper grades.  

Tack - The cohesive property between ink particles. The pulling power of ink against an adjacent surface. 

Tare weight - The weight of the container and/or wrapper deducted from the gross weight to determine the net weight of the contents. On skids, tare weight is the weight of the wooden pallet and wrapper. On rolls, it is the weight of the core, plug, and wrapper. 

Tear - This test measures the amount of energy required to tear a sheet of paper. Tear strength can be an important performance factor to a printer or converter of bags, maps, books, or envelopes. 

Tensile strength - Relates to the stress and strain to which paper is subjected in its many end use applications. It is defined as the maximum force required to break a paper strip of a given width under prescribed laboratory conditions. The degree and quality of fiber bonding and the type of fibers used are the most important factors affecting tensile strength. 

Titanium Dioxide - Chemical substance used as loading for coating material to increase the whiteness and brightness of a sheet and contribute toward its opacity.

TOFC - Trailer on Flat Car.  Trailer with chassis (wheels) attached rides on top of flat car.

Tolerance - Permissible degree of variation from a pre-set standard. 

Ton - A unit of weight equal to 2000 pounds.

Transparent ink - Ink which permits previous printing to show through, permitting the two colors to blend and produce a third. 

Trapping of inks - Printing ink property making it possible to superimpose one color on another. 

Trim - The process of combining various roll sizes that have a common grade, caliper core size, diameter, and wind direction to constitute an acceptable percent of the maximum salable width of a reel of paper from a paper machine. 

Twin-wire paper making machine - Paper machine using two vertical wires.  The pulp slurry is injected between the two wires with water being removed from both sides of the sheet of paper as it is formed.  Paper made on such a machine does not have the two-sidedness of paper made on a Fourdrinier machine.  

UV - Ultra violet radiation method of drying process color inks on high speed multicolor offset presses

Unbleached - Pulp which has been cooked but not bleached. 

Upcharge - Charge over and above the base price.

Virgin stock - Pulp obtained from wood, cotton or another cellulose source and not previously used in the papermaking process.  

Wash-up - Process of cleaning the rollers, plates, blankets and sometimes the fountain of a press .

Water finish - Resembles the machine glazed finish. Obtained by moistening the web with a fine spray of water as it passes through the calender stacks of the paper machine. Moisture thus applied softens the web of paper permitting it to be calendered to a smoother finish.

Watermark - In papermaking, the name or design produced by the raised pattern of the dandy roll on the paper machine. 

Wax pick - A test to determine the surface strength of paper or board. This test evaluates surface bonding strength and relates to the tendency for tacky inks to pick fibers or particles from paper surface.

Web - A continuous sheet of paper on a paper machine in roll form. 

Wet end - Beginning of the paper machine where the headbox, moving wire and press section are located. At this point the paper is still a suspension of fiber and water.

Wet strength papers - Once wet, ordinary papers lose most of their original dry- strength properties. Wet strength papers possess properties that resist disintegration and rupture when saturated with water. Papers are usually classified wet strength when they retain 15% or more of their dry-tensile strength. Superior quality wet strength papers may retain as much as 50% or more of their dry strength following immersing in water.

White liquor - The cooking chemicals applied to the digester - sodium hydroxide and sodium sulfide.

Whiteness - So called white papers have a definite hue. Most are made with a blue- white tint. Whiteness of pulp and paper is generally indicated by its brightness which is reflectance of a wave length of blue light.

Wire mark - On the bottom or wire side of the paper, these are impressed traces of the machine wire. 

Wire side - The side of the sheet next to the wire during manufacture; opposite from the felt side. 

With the grain - Relating to a direction parallel to the grain of paper. 

Wood chip - The coin-sized piece of wood which is cooked in the digester. It is processed in the woodyard. Logs are debarked and cut into these small pieces in the chipper to make the wood chip.

Wood-free - Paper grades which do not contain mechanically pulped fibers.

Woodyard - The area in a mill where logs are stored, debarked, and chipped. Most modern woodyards process tree length logs. A satellite woodyard refers to a remotely located inventory point for cut timber.