PULP AND PAPER DICTIONARY
This page contains definitions of the terms, words and phrase commonly used in pulp and papermaking, printing, converting and paper trading.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
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.
FACIAL TISSUE A tissue paper product primarily used on the face. Sometimes inappropriately called Kleenex(R), which is a brand name owned and developed by Kimberly Clark many decades ago. Softness, especially the surface smoothness component, is highly valued in facial tissue, and especially in the "ultra premium" category. Many facial tissues have special materials added to improve the consumer's experience of the softness, through a process called lotionizing.
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 fibres 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 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.
FEMALE When applied to an embossing pattern that is engraved into the surface of an embossing roller or plate, "female" means that the pattern is composed of elements that are recessed into a flat background, like potholes in pavement. A male pattern is composed of elements that are raised up from a flat background, like mesas in a desert. However, many patterns are too complex to be described overall either as male or as female. These terms, male and female, work better when applied to a single embossing element.
FIBRE 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.
FIBRE AXIS RATIO Ratio of fibre width to fibre thickness.
FIBRE COARSENESS Weight per unit length of fibre.
FIBRE CUT A fibre cut is a short, straight cut located on the edge of the web, caused by a fibre imbedded in the web of paper.
FIBRE DEBRIS Pieces of material which has been separated from the main body of the fibre.
FIBRE FLOC Fibres that have agglomerated as a result of poor formation.
FIBER ORIENTATION Refers to the alignment of the fibres in the sheet.
FIBERBOARD Board made from defibrated wood chips, used as a building board.
FIBRILLATION A structural change occurring in the walls of chemical pulp fibres during beating.
FIBRILLAE OR FIBRILS String-like elements that are loosened from the paper fibres during the beating process. They aid in the bonding processes when paper is being manufactured.
FILLER Any inorganic substance added to the pulp during manufacturing of paper. Most of fillers are cheaper than fibres and so fillers are added to reduce the overall cost of paper. Fillers are also used to improve optical and other printability related properties. Fillers improve opacity and brightness. Fillers reduce strength properties of paper.
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 fibre 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. A group of processes which add value by changing the intrinsic properties of the paper after the paper is formed and dried, after all of the papermaking processes have ended. Examples include embossing, calendering, printing, lotionizing, laminating, etc. Most finishing processes are done on converting machines.
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, fibre bundles, and/or improperly prepared chemical additives in the stock.
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 vapour pressure of the liquid. Flashing occurs in blow tank during blowing.
FLY LEAF/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).
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 colouring 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 colour 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.
FLUTED EDGE CRUSH Measures the edgewise compression strength of corrugating medium using a fluted test specimen per Tappi T824.
FLUTE (A,B,C,E,F&G) These letters define the type of corrugated material in terms of the number of corrugations per unit length and the height of the corrugations - specifically these are:
Flute - Corrugations per metre - Height of corrugation (mm)
A 105 - 125 4.5 - 4.7
B 150 - 185 2.1 - 2.9
C 120 - 145 3.5 - 3.7
E 290 - 320 1.1 - 1.2
F 410 - 420 0.7 - 0.8
G 550 - 560 0.5 - 0.6
FLUTING Waves or corrugation in heat-set web offset prints that runs in the press direction.
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.
FOLDING Doubling up a sheet of paper so that one part lies on top of another. Folding stresses the paper fibres. To create a smooth, straight fold, heavy papers like cover stocks and Bristol need to be scored before they're folded.
FOLDING - One of the converting processes.
FOLDING BOXBOARD Single or multi-layer paperboard made from primary and/or secondary fibres, 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 fibres in a sheet of paper. The more uniform and tightly bound the fibres, the better the sheet will print and look. Close Formation - Uniform distribution of fibres. Cloudy formation: A spotty, non-uniform dispersion of fibres, 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 activity at high speeds – this greatly enhances the formation.
FOUNTAIN ROLLER The roller on a printing machine which initiates the supply of moisture to the damping system.
FOUR-COLOUR PRINTING PROCESS A printing method that uses dots of magenta (red), cyan (blue), yellow, and black to simulate the continuous tones and variety of colours in a colour image. Reproducing a four-colour image begins with separating the image into four different halftones by using colour filters of the opposite (or negative) colour. For instance, a red filter is used to capture the cyan halftone, a blue filter is used to capture the yellow halftone, and a green filter is used to capture the magenta halftone. Because a printing press can't change the tone intensity of ink, four-colour process relies on a trick of the eye to mimic light and dark areas.
Each halftone separation is printed with its process colour (cyan, magenta, yellow, and black). When we look at the final result, our eyes blend the dots to recreate the continuous tones and variety of colours we see in a colour photograph, painting, or drawing.
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 A sheet printed on one side and folded first vertically and then horizontally to produce a four-page folder.
FULLY BLEACHED PULP Pulp that has been bleached to the highest brightness attainable (> 60 ISO).
FURNISH A blend of fibres, pigments, dyes, fillers and other materials that are fed to the wet end of the paper machine.
FUZZ Fibrous projections on the surface of a sheet of paper, caused by excessive suction, insufficient beating or lack of surface sizing. Lint appears in much the same manner but is not attached to the surface.