Printing Paper

Question: What Is Uncoated Paper?

Answer: Uncoated paper does not have a coating, meaning that it is just the natural, untreated paper stock you choose for your print job. Uncoated papers can be written on and overprinted so, are commonly used for letterheads and compliment slips.

Question: What is Absorbency?

Answer: In the graphics industry, absorbency refers to the papers ability to soak up liquid. Absorbency is measured according to standardised test procedures. uncoated grades usually have a higher absorbency than uncoated.

Question: What is Acid-free Paper?

‍Answer: Acid-free Paper is paper that contains no acid which can have a detrimental effect on its ageing resistance.

Question: What is Ageing?

Answer: Ageing is a deterioration in properties relating to time and storage conditions.

Question: What is Apparent Density?

Answer: Apparent density is a measure of a papers compactness or specific weight. Calculated by dividing grammage by thickness.(See What is Bulk).

Question: What is Archival Paper?

Answer: Archival Paper is a paper made from rags or cotton with particularly high capabilities and protection against wear during handling. Should also be able to handle the requirement for paper for permanent documents.

Question: What is Ash Content?

Answer: Ash content is a value which indicates the quantity of filler in an uncoated paper. Given as a percentage. The ratio of the mass of the residue after combustion to the mass before combustion.

Question: What is Beating?

Answer: Beating is the mechanical treatment of the stock to improve the ability of the fibres to form paper. Beating is normally carried out in a refiner or a hollander.

Question: What is Board?

Answer: Grammages of between 350 and 1000 gm2 are called Board.

Question: What is Brightness?

Answer: Brightness is the ability of a paper surface to reflect light. Brightness is measured according to a standardised test procedure such as ISO 3688 or ISO 2470. Brightness should not be confused with whiteness.

Question: What is Bulk?

Answer: Bulk is the reciprocal of the density. Normally referring to the paper thickness divided by the grammage. A measure of volume which reveals how porous or compact a paper is. Expressed in m3ton, dm3kg 1kg or mlg for example. Low bulk is thin and heavy, high bulk is thick and light.Paper can have the same grammage i.e. 150 gsm but have half the bulk.

Question: What is Bursting Strength?

Answer: Bursting strength is the maximum pressure that can be exerted at right angles to a paper surface before rupture occurs.

Question: What is Cellulose?

Answer: Cellulose is an organic compound. A carbohydrate with very long chains of molecules. The base material in the production of paper grade pulp.

Question: What is Chemical Pulp?

Answer: Chemical Pulp is a raw ingredient of paper produced by extracting cellulose fibres from wood through cooking with chemical additives.

Question: What is Chemi-Groundwood?

Answer: Chemi-Groundwood is a chemimechanical pulp produced by grinding wood.

Question: What is Chlorine-free paper?

Answer: Chlorine-free paper is a paper made entirely without chlorine i.e. paper made from unbleached pulp or from pulp bleached using a chlorine free method.

Question: What is CIE Whiteness?

Answer: CIE is Commission Internationale d'Eclairage. An international commission that has developed a colour system now an ISO standard. CIE whiteness is based on this system and corresponds well with the eyes perception of whiteness. The value is determined using a spectrophotometer whereby the light reflected from the paper is split into different shades and converted into whiteness using the CIE equation. A high value means high whiteness. See also ISO witness.

Question: What is Coated Paper?

Answer: Coated paper refers to paper grades with an even surface to ensure good printing properties.A slip is applied to the surface consisting primarily of binding agent and pigment.

Question: What is a Coating Slip?

Answer: A coating slip is applied to a paper to produce an even surface. Consists of pigment in binding agent solution as well as dyes dispersing agents viscosity regulator etc. if required.

Question: What is a Cobb number?

Answer: The Cobb number is the amount of water absorbed by one square metre of paper in a given time. The Cobb number is determined according to the standardised test procedures and is expressed in grams

Question: What is Cross Direction?

Answer: Cross Direction is the direction of a paper that is perpendicular to the machine direction.

Question: What is Curl?

Answer: Curl is the change in shape that can occur on the surface of a sheet of paper when the sheet tries to roll itself into a cylinder.

Question: What are Double Fourdrinier and Twin Fourdrinier Machines?

Answer: A paper or board machine with two separate fourdrinier wire parts, the two webs of which are crouched together to form two-ply paper or two-layer board.

Question: What is a Drying Section?

Answer: A Drying Section is the section of a pulp-drying machine or paper machine where any remaining water is evaporated.

Question: What is dry Solids Content and Dry Matter Content?

Answer: This is the ratio of a papers mass after drying to that before drying.

Question: What is a Dummy?

Answer: A dummy is a sample or proposal for a printed product.

Question: What is ECF?

Answer: ECF is a bleaching method that does not use chlorinein gas form. Therefore called Elementary Chlorine Free bleaching. Bleaching with chlorine dioxide is ECF bleaching.

Question: What is a Felt Mark?

Answer: A Felt mark is an impression of the paper machines felt which is visible on the paper after printing.

Question: What is Fibreboard/Paper-board/ Cardboard?

Answer: Describes stiff paper or thin board. Grammages of between 170 and 340 gm2 usually come under this category.

Question: What is Fibre Composition?

Answer: Fibre Composition is the combination of different types of fibre in the pulp or paper.

Question: What is Fibre/Grain Direction?

Answer: Fibre or Grain Direction is the main orientation of the fibres in a paper. Primarily determined in the paper machine. Fibres orientate themselves during paper manufacture and can be tested by hanging a paper sheet over the edge of a table and noting which axis bends the most. The axis that bends the most has got the fibres running along the edge of the table. 210 x 297 means fibres are running in longest direction.

Question: What is Fibril?

Answer: Fibril is very fine, long, thin elements in the fibre wall. These in turn consist of even finer thread-like elements called micro-fibrils.

Question: What is Filler/Coating?

Answer: Filler or Coating are additives in the stock to produce different properties in the finished paper such as hue, elasticity, opacity and age-resistance. The most common fillers are ground marble, lime and clay.

Question: What is Fine Paper?

Answer: Fine Paper is paper intended to be printed or written on.

Question: What is Finishing?

Answer:Finishing encompasses various ways of dealing with a paper once it has been produced such as sheeting or rewinding

Question: What is Fluorescent Whitening Agent?

Answer: Fluorescent Whitening Agent is a chemical additive to make a paper appear whiter by converting the ultra-violet radiation into a bluish light.

Question: What is the Fold Number?

Answer: Fold Number is the number of double folds a sample paper strip can withstand before a break occurs.

Question: What is Formation?

Answer: Formation is the way in which fibres are distributed and mixed in a sheet of paper.

Question: What is Glazing?

Answer: Glazing is a process at the end of the paper process for increasing the papers smoothness and gloss. The process produces a high image quality but detracts from opacity and stiffness. Is conducted in the Calendering machine.

Question: What is Grammage?

Answer: Grammage is a measure of a papers weight. determined by dividing mass by area and expressed in gms ie 150 gms.

Question: What is Groundwood Pulp?

Answer: Ground-wood Pulp is a mechanical pulp, manufactured by grinding logs against coarse stones.

Question: What is Hardwood Pulp?

Answer: Hardwood Pulp is pulp produced from hardwood.

Question: What is the Head Box?

Answer: A Head Box is found at the start of the paper machine. it is where the stock is accelerated and sprayed onto the wire at the right speed. Varying the speed, concentration and flow creates papers of different grammages.

Question: What is a Hollander?

Answer: A Hollander is a mechanical mill used to treat fibrous material in water. The mill comprises of rotating blades that process the fibres. The machine was invented in Holland in the 17th century.

Question: What is Internal Bond-Strength/Z-Strength?

Answer: Refers to the maximum tensile force that e.g. a paper can withstand, specifically to force applied perpendicular to the papers plane.

Question: What is ISO Brightness?

Answer: ISO Brightness is the brightness of a paper, measured with an instrument according to ISO 2469. ISO = InternationalStandards Organisation.

Question: What is a Knot/Lump/Nodule?

Answer: A Knot/Lump or Nodule can occur in the paper stock as a small fibre cluster, either due to entangled fibres or incomplete defibration.

Question: What is Kraft Paper?

Answer: Kraft Paper is a strong paper made primarily from sulphate pulp, also called kraft pulp.

Question: What is Lamination?

Answer: Lamination involves gluing two sheets together to achieve a higher grammage. The added surface layer can be something other than a sheet of paper, e.g liner, cover paper, plastic film or metal foil.

Question: What is Lignin?

Answer: Lignin is a substance found in wood that occurs inwood-containing paper. The lignin gradually yellows - as does the paper.

Question: What is Long Grain?

Answer: Long Grain is a sheet cut so that the fibre direction runs parallel with the longer side. The sheet is therefore narrow in the fibre direction.

Question: What is Low-Chlorine Paper?

Answer: Low-Chlorine Paper is paper manufactured with low chloro-organic discharge - max 25% of the normal value for chlorine-bleached paper.

Question: What is LWC Paper?

Answer: Light Weight Coated paper is coated paper of low grammage.

Question: What is Machine Direction?

Answer: Machine Direction is the direction in the paper which corresponds to the lengthwise direction of the web. Comparable to fibre direction

Question: What is Machine Finishing?

Answer: Machine Finishing relates to glazing in a machine stack.

Question: What is Mechanical Pulp?

Answer: Mechanical Pulp is produced by extracting cellulose fibres from wood by mechanical beating.

Question: What is Moisture Content?

Answer: All paper contains a certain proportion of water.The ratio of the mass of water in a moist material to the total mass of the material. Both the absolute and the relative moisture content are measured.

Question: What is Neutral Size?

Answer: Neutral Size is the polymer size which is added to the paper stock at a pH of 7 - 8.

Question: What is Newsprint?

Answer: Newsprint is paper manufactured mainly from mechanical pulp, used for daily newspapers and similar printed matter. Grammage 40-50 g/m2.

Question: What is OBA?

Answer: OBA or Optical Brightening Agent/Optical Whiteners are completely synthetic substances which refract light and make it appear white to the human eye.

Question: What is OCR Paper?

Answer: Optical Character Recognition Paper is woodfree paper intended for automatic optical scanning.

Question: What is Offset Paper?

Answer: Offset paper is paper intended for use in offset printing and generally has good picking resistance.

Question: What is Opacity?

‍Answer: Opacity is a measure of how much light a paper does not let through. It depends on how well a paper surface can distribute and absorb light. Altered during printed process then referred to as print opacity.

Question: What is Paper?

Answer: The paper production method originated in China in around 150BC. Nowadays, paper consists mainly of ground wood-pulp or wood cellulose. Paper comes in a host of different categories and is sold in sheet or reel formats. In certain contexts, products of up to 225g/m2 are considered to be paper.

Question: What is Paper for Permanent Documents?

Answer: Paper for Permanent Documents is paper used for archiving with a good ability to withstand changes and degradation over a long period.

Question: What is Porosity?

Answer: Porosity is a measure of density in paper.

Question: What is Pulp?

Answer: Pulp is a fibre material used for making paper.

Question: What is Pulpwood?

Answer: Pulpwood is wood intended for the manufacture of pulp.

Question: What is Ream?

Answer: Ream is a pack of 500 identical sheets of paper. In some countries a ream refers to a different number of sheets.

Question: What is Reel Core?

Answer: Reel Core is a board tube used as the centre of a paper reel. The core consists of several wound plies of paper which are then laminated using a binding agent.

Question: What is Recycled/Secondary Fibre?

Answer: Relates to fibre material which has previously been used in a paper or board products.

Question: What is Recycled Paper?

Answer: Recycled Paper is paper whose fibre content consists completely or mainly of recycled fibres. Common recycled papers are news print and cardboard.

Question: What is Rewinding?

Answer: Rewinding is the transfer of a web from a reel.Performed in a machine called a rewinder.

Question: What is Roughness?

Answer: Roughness describes the topographical properties of a paper surface. Expressed in Bendtsen. To reduce roughness, paper is calendered i.e. smoothed, polished and compressed.

Question: What is Shading?

Answer: Shading is a colour dye added to paper to achieve a particular shade and to avoid colour differences in paper manufactured at different times.

Question: What is Sheeting?

Answer: Sheeting involves dividing a web or several webs into sheets by cross cutting or angle cutting in a special sheet-cutting machine.

Question: What are Shives?

Answer: Shives are fibre bundles in pulp or paper which derive from incomplete fibre separation during the pulping process.

Question: What is Short Grain?

Answer: Short Grain is a paper web which is cut into sheets so that the short sides of the sheets are parallel to the machine direction.

Question: What is Size?

Answer: Size is used in the paper industry to refer to the additive applied to the paper surface or stock. Adding size to the surface is called surface sizing. It also prevents moisture, for example, from spreading in the paper.

Question: What is Size Press Pigmented Paper?

Answer: Relates to paper that has been given a thin layer of coating.

Question: What is Softwood Pulp?

Answer: Softwood Pulp is a pulp produced from softwood e.g.pine or spruce.

Question: What is Stock?

Answer: Stock is the mixture of ingredients required to make a particular grade of paper.

Question: What is Stock Preparation?

Answer: Stock Preparation is all treatment of the stock before it reaches the paper machine.

Question: What is Stock Sizing?

Answer: Stock Sizing is a process whereby size is added to the stock to prevent aqueous solutions from penetrating and spreading in the paper.

Question: What is a Suction Box?

Answer: A Suction Box is a box which uses induced suction to remove water from a felt or a stock-bearing wire which passes over the box.

Question: What is Sulphate Pulp?

Answer: Sulphate Pulp is a chemical pulp made from sulphate cellulose. Often used for kraft paper.

Question: What is Sulphite Pulp?

Answer: Sulphite Pulp is a chemical pulp manufactured by cooking with sulphite cooking acid.

Question: What is Supercalender?

Answer: Supercalender is a calender normally separate from the paper machine, fitted with a number of calender bowls (rolls) stacked one upon the other, in such a way that elastic rolls alternate with smooth steel rolls, only one of which is driven, to glaze paper.

Question: What is Supercalendered paper?

Answer: Supercalendered Paper is a paper which has been glazed in a supercalender.

Question: What is Surface pH?

Answer: Surface pH is the value in the surface layer of e.g.a moistened paper sample.

Question: What is Surface Sizing?

Answer: Surface Sizing is sizing whereby the size is applied to the surface of the paper. The idea is to improve the picking resistance and printability of the paper.

Question: What is Tambour?

Answer: Tambour is a reeling drum which the finished paper is wound onto after production.

Question: What is TCF?

Answer: TCF is Totally Chlorine Free pulp bleached using no chlorine containing chemicals.

Question: What is Tearing Resistance?

Answer: Fine Paper is paper intended to be printed or written on.

Question: What is Finishing?

Answer: Tearing Resistance is a paper industry term for the force required to tear a sheet of paper under certain fixed conditions.

Question: What is Tensile Strength?

Answer: Tensile Strength is the maximum pulling force a paper can withstand before tearing. Tensile strength is determined by a standardised test procedure such as ISO 1924-1

Question: What is Thickness in Stack?

Answer: The thickness of paper will bulk differently in single sheet and within a book. Paper is therefore sometimes measured in stack to simulate this. Thickness in stack is determined by a standardised test procedure by dividing the thickness of the stack by the number of sheets in the stack.

Question: What is TMP?

Answer:TMP or Thermo Mechanical Pulp is mechanical pulp made by cooking wood chips in water before beating, with little or no use of chemical substances.

Question: What is Top Side?

Answer: Top Side is the side of the web or sheet which is opposed to the wire side.

Question: What are Trimmings?

Answer: Trimmings are strips of paper that have been cutaway from the printed job on a guillotine.

Question: What is a Twin Wire Machine?

Answer: A Twin Wire Machine is a paper machine in which the paper-making pulp is dewatered and formed between two wires.

Question: What is Two-Sidedness?

Answer: Two-Sidedness occurs when a difference occurs between the two sides of a paper during manufacture, e.g. in surface structure or shade.

Question: What is Unbleached Pulp?

Answer: Unbleached Pulp is a pulp that has not undergone treatment intended to increase its brightness.

Question: What is Uncoated Paper?

Answer: Uncoated Paper is the general name for paper grades that have not been coated. Often surface sized to increase surface strength.

Question: What is Virgin Fibre/Primary Fibre?

Answer: Relates to fibre which has not previously been used in any paper or board product. The opposite of recycled fibre.

Question: What is Wet Strength Agent?

Answer: Wet Strength Agent is an additive in the stock which gives paper increased strength when wet.

Question: What is Whiteness?

Answer: Whiteness is a visually perceived property characterised by high brightness, high light scattering and a minimum of colour.Refers to a value corresponding to the human eyes perception of the degree of whiteness.

Question: What is a Wiremark?

Answer: A Wiremark is the residual impression of the wire cloth in paper.

Question: What is a Wire Part?

Answer: A Wire Part is the section of a paper machine where the paper web is formed on a wire, between two wires or between a wire and some other surface. The wire acts as a net which lets through water, but not other particles in the stock.

Question: What is the Wire Side?

Answer: The Wire Side is the side of a web or sheet which has been in contact with the wire during manufacture.

Question: What are Wood Chips?

Answer: Wood Chips are made of wood that has been beaten down into small chips that are used in the pulpmill.

Question: What is Wood-Containing Paper?

Answer: Wood-Containing Paper is the term for paper containing more than 10% mechanical pulp and less than 90% chemical pulp, which has high strength, opacity and a natural feel.

Question: What is Woodfree Paper?

Answer: Woodfree paper is the term for paper containing less than 10% mechanical pulp and over 90% chemical pulp. Chemicals are used to seperate out celllulose fibres which is called chemical pulp which has high strength and resists ageing.

Question: What is Yellowing?

Answer: Different grades of paper are affected by exposure to light to different degrees. Long-term exposure to a lot of light makes a paper turn yellow. Standard ageing of paper over a long period also results in yellowing. Yellowing is caused by lignin in paper, usually mechanical stock, so avoid direct sunlight. Use a pure cellulose fibre paper to avoid ageing.

Question: What wood is used for paper?

Answer: Aspen, birch, eucalyptus, pine and spruce.

Question: What are Paper Fibres?

Answer: Softwood fibres are long therefore give stronger paper. Hardwood fibres are short giving good opacity. Pure cellulous fibres resist ageing i.e. non-yellowing and have high PH values.

Question: What is Filler?

Answer: Filler fills gaps between cellulose fibres which also softens paper. Gives increased opacity, better printing characteristics and can be calcium carbonate, china clay, limestone or kaolin.

Question: What is OBA?

Answer: OBA is Optical Brightening Agent to achieve higher brightness.

Question: What effect has temperature or air humidity on paper?

Answer: Can alter paper format. Increased temperature can dry out paper, reducing size. Increased air humidity can add moisture to the paper which is normally 3.5% - 6.5%. Any increase in RH% can add to paper dimension therefore storage is very important.

Question: What is Thickness?

Answer: Thickness is measured as grammage x bulk. Measured in micrometres um i.e. thousandths of a millimetre i.e. 400 mic.

Question: How is paper delivered?

Answer: Paper is usually delivered on pallets in bulk or ream packaged. Paper is wrapped to reduce the effect of temperature and humidity which paper is highly sensitive to and which can cause dimensional changes in fibres. Once changed never returns i.e. wavy edges.

Question: Can you supply a dummy and samples?

Answer: Yes, normally within 48-hours for most papers