The Manufacture of The Manufacture of Fine PapersFine Papers

Spring Semester 1999Spring Semester 1999

TEC 4562 Ink & Paper SubstratesTEC 4562 Ink & Paper Substrates

IntroductionIntroduction

““The ability of humans to supplement their The ability of humans to supplement their speech with the written word is an indication speech with the written word is an indication of a high degree of civilization.” of a high degree of civilization.”

From carvings on slabs of rock to paper, From carvings on slabs of rock to paper, humans have been able to devise a form of humans have been able to devise a form of communication that goes beyond speech.communication that goes beyond speech.

The History of PaperThe History of Paper

What civilization invented paper?What civilization invented paper?– Ancient Egyptians?Ancient Egyptians?

– Moors or ArabsMoors or Arabs

– Persians?Persians?

– Aztecs?Aztecs?

– Japanese?Japanese?

– Chinese?Chinese?

Pre-Paper MediaPre-Paper Media

The following is a list of pre-paper media The following is a list of pre-paper media developed by early humans:developed by early humans:– WoodWood

– MetalMetal

– StoneStone

– LeavesLeaves

– CeramicsCeramics

– Bark Bark

– PapyrusPapyrus

– ParchmentParchment

– ClothCloth

Egyptians and PapyrusEgyptians and Papyrus

The papyrus developed before 2,200 B.C. by The papyrus developed before 2,200 B.C. by the Egyptians was not considered true paper.the Egyptians was not considered true paper.

The reason papyrus and the other materials The reason papyrus and the other materials did not qualify as paper was due to the way it did not qualify as paper was due to the way it is formed from a liquid suspension of is formed from a liquid suspension of individual fibers into a mat or sheet.individual fibers into a mat or sheet.

It was made by slicking the plant’s stalk from It was made by slicking the plant’s stalk from end-to-end into very thin blades and then end-to-end into very thin blades and then laminating them into something of a weave.laminating them into something of a weave.

It appears similar to cloth.It appears similar to cloth.

The History of PaperThe History of Paper

Although papyrus is not structured like the Although papyrus is not structured like the writing or printing surfaces in use today—it writing or printing surfaces in use today—it became the Latin word for paper.became the Latin word for paper.

Nearly 2,000 years later, the Chinese created Nearly 2,000 years later, the Chinese created the first true or practical form of paper.the first true or practical form of paper.

They did this by reducing raw material into They did this by reducing raw material into individual fibers and then forming them into a individual fibers and then forming them into a mat or sheet. mat or sheet.

The Inventor of PaperThe Inventor of Paper

It is widely accepted that Ts’ai Lun, a Chinese It is widely accepted that Ts’ai Lun, a Chinese court official, invented paper in 105 AD.court official, invented paper in 105 AD.

Ts’ai Lun’s PaperTs’ai Lun’s Paper

Mulberry BarkMulberry Bark Hemp WasteHemp Waste Old RagsOld Rags Fish NetsFish Nets

The Wove Mold ProcessThe Wove Mold Process

This process was devised by the ChineseThis process was devised by the Chinese– Pulp was made by beating bark (Pulp Friction), which had Pulp was made by beating bark (Pulp Friction), which had

been washed and boiledbeen washed and boiled

– During the washing and boiling process, the pulp fibers During the washing and boiling process, the pulp fibers were separated using smooth-edged stones and sticks. were separated using smooth-edged stones and sticks.

The Laid MoldThe Laid Mold

Consisted of a flexible cover made of thin Consisted of a flexible cover made of thin strips of bamboo held together with silk or strips of bamboo held together with silk or some other similar threadsome other similar thread

It was placed on a wooden frame.It was placed on a wooden frame. The papermaker would hold the two together The papermaker would hold the two together

and dip them in a vat of water and fibers.and dip them in a vat of water and fibers.

The Laid Mold (continued)The Laid Mold (continued)

The papermaker would lift the mold and let The papermaker would lift the mold and let the water drain away.the water drain away.

This formed the sheet.This formed the sheet. The layer of wet paper and light bamboo were The layer of wet paper and light bamboo were

lifted from the wooden frame and placed on a lifted from the wooden frame and placed on a smooth stone with the wet fiber mat facing smooth stone with the wet fiber mat facing down.down.

The light bamboo matting was then rolled The light bamboo matting was then rolled from the paper leaving a wrinkle-free sheet to from the paper leaving a wrinkle-free sheet to be dried.be dried.

The mold was reusable.The mold was reusable.

Therefore,Therefore,

the Laid Mold was considered better than the the Laid Mold was considered better than the Wove MoldWove Mold

Historical significance of Historical significance of paper...paper...

Early use as a symbol for money to burn over Early use as a symbol for money to burn over graves of the deadgraves of the dead

175 A.D. - Paper replaced silk as a medium for 175 A.D. - Paper replaced silk as a medium for writing.writing.

610 A.D. the Japanese began to make paper610 A.D. the Japanese began to make paper 750 A.D. the battle fought between Muslims 750 A.D. the battle fought between Muslims

and Chinese at Samarkand in Turkestan (now and Chinese at Samarkand in Turkestan (now part of Uzbekistan at formerly part of the part of Uzbekistan at formerly part of the Soviet Union) spurred the development of Soviet Union) spurred the development of paper outside China’s domain.paper outside China’s domain.

875 A.D. - First known use of toilet paper.875 A.D. - First known use of toilet paper. Late 900’s - Playing cards invented.Late 900’s - Playing cards invented. Mid 15th century - Johannes Gutenburg’s Mid 15th century - Johannes Gutenburg’s

invention of movable type spurred the invention of movable type spurred the production for paper necessary for the production for paper necessary for the production of books.production of books.

The “Paper Renaissance”- The “Paper Renaissance”- 17th to 19th Century Europe 17th to 19th Century Europe

France was the center of paper production...France was the center of paper production...– Exported papers to all of EuropeExported papers to all of Europe

– It possessed the best papermakers and the finest It possessed the best papermakers and the finest equipment in the world.equipment in the world.

France also experienced internal struggle and France also experienced internal struggle and unrest during the 17th century...unrest during the 17th century...– This caused their papermakers to flee to England, This caused their papermakers to flee to England,

Holland and America.Holland and America.

– The skilled French papermakers contributed to the The skilled French papermakers contributed to the English and Dutch paper manufacturers, thus, English and Dutch paper manufacturers, thus, transforming them into the “foremost paper transforming them into the “foremost paper manufacturers in Europe.”manufacturers in Europe.”

America’s First Paper MillAmerica’s First Paper Mill

Built in 1690 by William RittenhouseBuilt in 1690 by William Rittenhouse Location: PhiladelphiaLocation: Philadelphia Since that time, America has become the Since that time, America has become the

world’s largest producer of paper and pulp world’s largest producer of paper and pulp productsproducts

Fibers for PapermakingFibers for Papermaking

Fibers are defined as “...tough threadlike Fibers are defined as “...tough threadlike substances capable of being spun or woven, substances capable of being spun or woven, whether they be natural (vegetable, mineral, whether they be natural (vegetable, mineral, animal) or man-made.”animal) or man-made.”

In papermaking, animal fibers are not used at In papermaking, animal fibers are not used at all, and mineral fibers are used only all, and mineral fibers are used only occasionally.occasionally.

Vegetable fibers (cellulose) wet easily in a Vegetable fibers (cellulose) wet easily in a water medium and will form a strong bond to water medium and will form a strong bond to each other when dried in contact.each other when dried in contact.

Four Types of Cellulose FibersFour Types of Cellulose Fibers

Seed Hair FibersSeed Hair Fibers– Cotton fibersCotton fibers

Bast FibersBast Fibers– Flax plantFlax plant

– Only 5% of the flax plant is usable for paper Only 5% of the flax plant is usable for paper manufacturingmanufacturing

Grass FibersGrass Fibers– Wheat strawWheat straw

– Bagasse fiber (extracted from sugar cane stalks)Bagasse fiber (extracted from sugar cane stalks)

– Esparto grassEsparto grass

– Kenaf plantKenaf plant

Wood FibersWood Fibers

Seed Hair Fibers—Cotton PlantSeed Hair Fibers—Cotton Plant

Cotton fibers are Cotton fibers are very expensive.very expensive.

Used primarily for Used primarily for bank notes, high bank notes, high grade writing grade writing papers, maps—papers, maps—anything that anything that requires requires exceptional exceptional strength and strength and durability.durability.

Bast FibersBast Fibers

Obtained from the flax Obtained from the flax plant.plant.

Located inside the Located inside the stem.stem.

Only 5% usable for Only 5% usable for papermaking.papermaking.

Hemp and jute are Hemp and jute are other forms of bast other forms of bast fibers.fibers.

Hemp has been used Hemp has been used for cigarette and Bible for cigarette and Bible papers.papers.

Bast Fibers (continued)Bast Fibers (continued)

Jute obtained from new burlap cuttings or Jute obtained from new burlap cuttings or other sources…other sources…– It is used for heavy duty shipping tags and heavy pattern It is used for heavy duty shipping tags and heavy pattern

boards.boards.

Grass FibersGrass Fibers

Wheat StrawWheat Straw– Absorbs water readily.Absorbs water readily.

– Was used during World War II in England due to a severe Was used during World War II in England due to a severe shortage of pulpwood.shortage of pulpwood.

Bagasse fiberBagasse fiber– Made from crushed stalks of sugar cane.Made from crushed stalks of sugar cane.

– Used as a source of fuel for Sugar Mills.Used as a source of fuel for Sugar Mills.

Esparto PlantEsparto Plant– Has very little strength and does not split into fibrils Has very little strength and does not split into fibrils

easily.easily.

– Impractical for use in the United States because of the Impractical for use in the United States because of the distance from the source of supply.distance from the source of supply.

Grass Fibers (continued)Grass Fibers (continued)

Kenaf plantKenaf plant– Shows great potential for Shows great potential for

papermaking.papermaking.

– May produce 5 to 7 times more May produce 5 to 7 times more pulp/acre than pine.pulp/acre than pine.

– Grows to maturity in 120 days Grows to maturity in 120 days compared to 20 years for most compared to 20 years for most trees.trees.

Wood FibersWood Fibers

95% of all paper is made from wood fibers.95% of all paper is made from wood fibers. Deciduous hardwood trees, e.g., Oak, Gum, Deciduous hardwood trees, e.g., Oak, Gum,

Maple, Aspen, etc.Maple, Aspen, etc. Coniferous softwood trees, e.g., Pine, Spruce, Coniferous softwood trees, e.g., Pine, Spruce,

Fir, etc. (the softwoods produce a stronger Fir, etc. (the softwoods produce a stronger pulp).pulp).

Wood ProcurementWood Procurement

39% of the available forests in the United States 39% of the available forests in the United States are in the South.are in the South.

Private citizens own 3 quarters of land.Private citizens own 3 quarters of land. Paper industry uses specially designed Paper industry uses specially designed

equipment to harvest & prepare crops of trees:equipment to harvest & prepare crops of trees:– Power chain sawsPower chain saws

– Skidders-forest tractors are used for opening sections of Skidders-forest tractors are used for opening sections of land.land.

– Specially designed combines.Specially designed combines.

– Mechanized tree shears.Mechanized tree shears.

– Cranes, clamp trucks, truck dumpers.Cranes, clamp trucks, truck dumpers.

– Slashers saws.Slashers saws.

– Debarking drums.Debarking drums.

PulpingPulping

The objective of pulping is to separate the The objective of pulping is to separate the wood into individual fibers.wood into individual fibers.

Three broad classifications of pulping Three broad classifications of pulping methods:methods:– Mechanical (groundwood)Mechanical (groundwood)

– ChemicalChemical

– Combination (chemi-mechanical)Combination (chemi-mechanical)

Mechnical Pulping ProcessesMechnical Pulping Processes

Stone GroundwoodStone Groundwood– Mechanical process used to rip fibers from the logsMechanical process used to rip fibers from the logs

– Slurry of pulp formed from the grounded mix.Slurry of pulp formed from the grounded mix.

– Can be made from either hardwood or softwood.Can be made from either hardwood or softwood.

Refiner-Mechanical PulpingRefiner-Mechanical Pulping– Wood chips are pumped into rotating disks causing Wood chips are pumped into rotating disks causing

internal friction that generates heat.internal friction that generates heat.

– The heat from the refiner softens lignin. The heat from the refiner softens lignin.

Thermo-Mechanical PulpingThermo-Mechanical Pulping Chemi-Mechanical PulpChemi-Mechanical Pulp

To Make Groundwood Pulp...To Make Groundwood Pulp...

The bark is removed from the logs.The bark is removed from the logs. Then, the cut logs are forced by hydraulic or Then, the cut logs are forced by hydraulic or

steam pressure against a revolving grinding steam pressure against a revolving grinding stone in the presence of water.stone in the presence of water.

This treatment converts the wood into a pulp This treatment converts the wood into a pulp consisting of minute particles of both fibrous consisting of minute particles of both fibrous and nonfibrous portions of wood.and nonfibrous portions of wood.

The nonfibrous materials deteriorate when The nonfibrous materials deteriorate when left for some time in contact with air.left for some time in contact with air.

Therefore, paper made from this kind of pulp Therefore, paper made from this kind of pulp lacks permanency.lacks permanency.

Groundwood PulpGroundwood Pulp

This type of pulp is not as strong as chemical This type of pulp is not as strong as chemical pulp.pulp.

Groundwood pulp has to be mixed with other Groundwood pulp has to be mixed with other pulps, e.g., Newsprint—contains 80% pulps, e.g., Newsprint—contains 80% groundwood pulp and 20% chemical pulp.groundwood pulp and 20% chemical pulp.

It is highly suitable for products such as It is highly suitable for products such as wallpaper, paper towels, or lightweight wallpaper, paper towels, or lightweight catalog papers.catalog papers.

It is unexcelled in its ability to produce It is unexcelled in its ability to produce papers with high opacity, smoothness and ink papers with high opacity, smoothness and ink receptivity.receptivity.

Thermo-Mechanical PulpThermo-Mechanical Pulp

To make TMP, wood chips or sawdust are To make TMP, wood chips or sawdust are first softened by steam and then subjected, first softened by steam and then subjected, under pressure, to the defibering action of a under pressure, to the defibering action of a a disk-type refiner.a disk-type refiner.

This causes the fibers to completely separate This causes the fibers to completely separate from each other and suffer less damage than from each other and suffer less damage than those produced by the conventional those produced by the conventional groundwood pulp process.groundwood pulp process.

TMP is cleaner and stronger when compared TMP is cleaner and stronger when compared with groundwood pulp.with groundwood pulp.

Chemical PulpChemical Pulp

Chemicals are used to reduce wood chips Chemicals are used to reduce wood chips into fibers.into fibers.

This process separates each fiber from its This process separates each fiber from its bonding material—lignin.bonding material—lignin.– The adhesive qualities of lignin holds cellulose fibers The adhesive qualities of lignin holds cellulose fibers

together. together.

BleachingBleaching

The purpose of bleaching is to remove stains The purpose of bleaching is to remove stains caused by lignin.caused by lignin.

Major bleaching agentsMajor bleaching agents– chlorine, sodium hypochlorite, hydrogen peroxide, chlorine, sodium hypochlorite, hydrogen peroxide,

chlorine-dioxide, and oxygen.chlorine-dioxide, and oxygen.

Chlorine gas is one of the different bleaching Chlorine gas is one of the different bleaching systems that are used to remove lignin that systems that are used to remove lignin that remains in the pulp.remains in the pulp.– Chlorine gas is passed into the pulp-water mixture.Chlorine gas is passed into the pulp-water mixture.

– The gas reacts with whatever lignin that is left and The gas reacts with whatever lignin that is left and becomes chlorinated.becomes chlorinated.

– The chlorinated lignin is then removed when treated with The chlorinated lignin is then removed when treated with the caustic soda NaOH (Sodium Hypochlorite)the caustic soda NaOH (Sodium Hypochlorite)

Fourdrinier Paper Making Fourdrinier Paper Making MachineMachine

Nicolas Louis Robert invented the Nicolas Louis Robert invented the papermaking machine in 1798.papermaking machine in 1798.

Sealy Fourdrinier and Robert improved the Sealy Fourdrinier and Robert improved the original design of the papermaking machine original design of the papermaking machine to produce paper with a felt side and a wire to produce paper with a felt side and a wire side. side.

The paper is formed at the wet end of the The paper is formed at the wet end of the machine—after the pulp-water mixture has machine—after the pulp-water mixture has been refined.been refined.– FillersFillers

– Coloring materialColoring material

– SizingSizing

The HeadboxThe Headbox

The headbox spreads pulp and water mix The headbox spreads pulp and water mix evenly over the moving wire.evenly over the moving wire.– The pulp-water mixture containing the added fibers, The pulp-water mixture containing the added fibers,

coloring material and size is diluted with water to make coloring material and size is diluted with water to make “slurry” containing ½ % to 1 % of cellulose fibers.“slurry” containing ½ % to 1 % of cellulose fibers.

– The headbox must maintain the uniform delivery of The headbox must maintain the uniform delivery of dispersion of fibers across the width of the machine.dispersion of fibers across the width of the machine.

The Fourdrinier Wire The Fourdrinier Wire

The fourdrinier wire causes the forming of The fourdrinier wire causes the forming of paper at the wet end of the machine.paper at the wet end of the machine.– It is the section of the papermaking machine made up of It is the section of the papermaking machine made up of

a fine woven screen to let water drain away causing the a fine woven screen to let water drain away causing the pulp to remain to form a thin mat.pulp to remain to form a thin mat.

– Suction boxes remove water as the mat moves along the Suction boxes remove water as the mat moves along the wire.wire.

– Synthetic plastic fiber wires are used in modern Synthetic plastic fiber wires are used in modern papermaking machines.papermaking machines.

When the mat had left this stage of When the mat had left this stage of production it contains 75% water.production it contains 75% water.

PressesPresses

During this stage of production, the mat During this stage of production, the mat enters wet rollers carried by felt blankets to enters wet rollers carried by felt blankets to reduce the amount of water to 60 - 65%.reduce the amount of water to 60 - 65%.

It is during this stage that the thin mat or It is during this stage that the thin mat or paper begins to form a web or long ribbon.paper begins to form a web or long ribbon.

The paper continues through press rolls and The paper continues through press rolls and felt blankets to remove water.felt blankets to remove water.

DryersDryers

Steam heated cylinders dry paper to 5% Steam heated cylinders dry paper to 5% moisture.moisture.

Size PressesSize Presses

Size press applies 10 % starch solution to Size press applies 10 % starch solution to both sides of paper.both sides of paper.

DryersDryers

Second dryer unit removes moisture applied Second dryer unit removes moisture applied to sheet in size press.to sheet in size press.

Calender-ReelCalender-Reel

Polished rollers iron and control thickness of Polished rollers iron and control thickness of sheet. Reel winds paper on mandrel.sheet. Reel winds paper on mandrel.

WinderWinder

Winder unwinds paper from mandrel, passes Winder unwinds paper from mandrel, passes sheet across slitter to trim edges and cut sheet across slitter to trim edges and cut paper to final width.paper to final width.

Twin Wire MachinesTwin Wire Machines

This method of papermaking was developed This method of papermaking was developed to improve the efficiency of the fourdrinier to improve the efficiency of the fourdrinier design.design.

Two vertical sides restrain the furnish to Two vertical sides restrain the furnish to permit the extraction of water from both sides permit the extraction of water from both sides of the paper.of the paper.

Increase machine speeds and reduction in Increase machine speeds and reduction in drying.drying.

Cylinder MachineCylinder Machine

This type of machine is designed for making This type of machine is designed for making extremely heavyweight paper and/or multi-ply extremely heavyweight paper and/or multi-ply products used in the manufacture of products used in the manufacture of corrugated containers, folding cartons, and corrugated containers, folding cartons, and solid fiber boxes.solid fiber boxes.

All layers for multi-ply products can be All layers for multi-ply products can be manufactured with all layers formed in a manufactured with all layers formed in a single continuous operation.single continuous operation.

Two types of cylinder vats: contraflow and Two types of cylinder vats: contraflow and direct flow.direct flow.

Paper (handout)Paper (handout)

1. The 1. The ChineseChinese are given credit for inventing the are given credit for inventing the technique of papermaking.technique of papermaking.

2. To make a continuous supply of wood, the 2. To make a continuous supply of wood, the basic raw material for making paper, basic raw material for making paper, paperpaper companies operate tree farms.companies operate tree farms.

3. Pulp 3. Pulp fibersfibers are obtained from, woody fibrous are obtained from, woody fibrous materials, and reclaimed products are made materials, and reclaimed products are made from these materials.from these materials.

4. Wood pulp sources are divided between 4. Wood pulp sources are divided between softwoodsoftwood (coniferous) and (coniferous) and hardwood hardwood (deciduous).(deciduous).

Paper (handout) continuedPaper (handout) continued

5. All paper fibers are made of a compound 5. All paper fibers are made of a compound called called cellulosecellulose..

6. 6. LigninLignin serves as a binder and support for the serves as a binder and support for the cellulose fibers of woody plants.cellulose fibers of woody plants.

7. 7. Groundwood Groundwood pulp process uses almost all of pulp process uses almost all of the substance in wood to make paper.the substance in wood to make paper.

8. The manufacturer of 8. The manufacturer of chemicalchemical pulp uses pulp uses chemical action to dissolve some of the chemical action to dissolve some of the wood’s substances to make higher quality wood’s substances to make higher quality paper.paper.

Paper (handout) continuedPaper (handout) continued

9. The chemical-mechanical pulp method 9. The chemical-mechanical pulp method combines mechanical and combines mechanical and cookingcooking separation separation processes.processes.

10. 10. OpacityOpacity refers to the amount of light that can refers to the amount of light that can be seen through a sheet of paper.be seen through a sheet of paper.

11. In all three pulping methods, 11. In all three pulping methods, washingwashing is used is used to remove all traces of chemicals and dirt from to remove all traces of chemicals and dirt from wood fibers.wood fibers.

12. 12. True.True. Groundwood pulp is often referred to as Groundwood pulp is often referred to as mechnical pulp because it has been reduced to mechnical pulp because it has been reduced to fibers by a mechanical grinding process.fibers by a mechanical grinding process.

Paper (handout) continuedPaper (handout) continued

13. The pulp selected for 13. The pulp selected for bleachingbleaching is treated is treated with chlorine and similar chemical solutions with chlorine and similar chemical solutions to whiten the paper fibers.to whiten the paper fibers.

14. The primary purpose of adding 14. The primary purpose of adding fillersfillers to the to the pulp is to strengthen its properties.pulp is to strengthen its properties.

15. 15. SizingSizing is used to helpl make paper less is used to helpl make paper less absorbent and more water repellent, so it will absorbent and more water repellent, so it will not allow ink to spread.not allow ink to spread.

16. 16. DyesDyes and and pigmentspigments are added to pulp during are added to pulp during washing to give paper color.washing to give paper color.

Paper (handout) continuedPaper (handout) continued

17. The forming of paper starts at the 17. The forming of paper starts at the wet endwet end of of the papermaking machine. Then processed the papermaking machine. Then processed pulp, which is 99% water, flows rapidly over pulp, which is 99% water, flows rapidly over an apron the width of the machine onto a an apron the width of the machine onto a moving mesh wire screen.moving mesh wire screen.

18. Where the paper touches the screen, it 18. Where the paper touches the screen, it shows a mesh pattern. This is called the shows a mesh pattern. This is called the wirewire side of the paper.side of the paper.

Paper (handout) continuedPaper (handout) continued

A. 99.0 - 99.5 %A. 99.0 - 99.5 % B. 75%B. 75% C. 60 - 65%C. 60 - 65%

19. Identify the water content and machine sections of a 19. Identify the water content and machine sections of a typical papermaking machine operation in the mill.typical papermaking machine operation in the mill.

D. 5%D. 5% E. 35%E. 35% F. 4.7 - 5.5%F. 4.7 - 5.5%

Paper Making MachinePaper Making Machine

G. HeadboxG. Headbox H. FourdrinierH. Fourdrinier I. PressesI. Presses J. DryersJ. Dryers

K. SizeK. Size L. DryersL. Dryers M. Calender-ReelM. Calender-Reel N. Winder PressN. Winder Press

Paper (handout) continuedPaper (handout) continued

20. As the paper starts to form, the pulp passes 20. As the paper starts to form, the pulp passes under a under a dandydandy roll to produce a surface finish roll to produce a surface finish on the paper. The roll is made of mesh wire.on the paper. The roll is made of mesh wire.

21. The paper begins to form into a 21. The paper begins to form into a webweb, or long , or long ribbon as it passes through the papermaking ribbon as it passes through the papermaking machine.machine.

22. The ribbon of paper continues through 22. The ribbon of paper continues through press rollspress rolls and and felt blanketsfelt blankets, which remove , which remove more water.more water.

Paper (handout) continuedPaper (handout) continued

23. The side of the paper that is in contact with 23. The side of the paper that is in contact with the felt blanket is called thethe felt blanket is called the felt felt side of the side of the paper.paper.

24. 24. CalenderCalender rolls are made of smooth iron to rolls are made of smooth iron to polish the paper and give it a very smooth polish the paper and give it a very smooth finish.finish.

25. Sheet-fed offset paper must have more 25. Sheet-fed offset paper must have more strength than other printer processes because strength than other printer processes because of the of the tackier inktackier ink..

26. The basis weights of paper generally used for 26. The basis weights of paper generally used for web offset range from about web offset range from about 20 - 8020 - 80 pound. pound.

Paper (handout) continuedPaper (handout) continued

27. Joining the ends of two rolls of paper is 27. Joining the ends of two rolls of paper is referred to as referred to as splicingsplicing..

28. There are eight paper properties which must 28. There are eight paper properties which must be considered for each job:be considered for each job: GrainGrain FinishFinish Pick ResistancePick Resistance Brightness and Basis weightBrightness and Basis weight FlatnessFlatness Ink setting and sizingInk setting and sizing Moisture absorbency and resistanceMoisture absorbency and resistance OpacityOpacity

29. Fibers tend to align themselves in the paper 29. Fibers tend to align themselves in the paper as it passes through the machine. This as it passes through the machine. This alignment of fiber is referred to as the alignment of fiber is referred to as the graingrain of of the paper.the paper.

30. 30. TearTear strength in paper increases with strength in paper increases with increased fiber strength.increased fiber strength.

31. The term 31. The term finishfinish refers to any action refers to any action performed to the surface of the sheet of performed to the surface of the sheet of printing paper that affects its surface.printing paper that affects its surface.

32. 32. CoatedCoated papers are exceptionally smooth, papers are exceptionally smooth, since they are subjected to an additional since they are subjected to an additional smoothing process.smoothing process.