Paper types

Paper can be produced with a wide variety of properties, depending on its intended use:

  • Printing papers of wide variety. This includes book paper, cartridge paper, newsprint, rice paper, silk paper, rag paper, cotton paper.
  • Writing paper suitable for stationery requirements. This includes ledger, bank, and bond paper.
  • Blotting papers containing little or no size.
  • Photography papers: matt, glossy and silk
  • Inkjet art papers
  • Drawing papers usually with rough surfaces used by artists and designers including Bristol Board, thick ink papers, pastel papers, graph and isometric paper, construction paper, sugar papers, papers for oil pastel, Moleskin sketch papers, tracing papers
  • Painting papers eg watercolour
  • Printmaking papers for use in a printing press or for hand printing. This includes Japanese hosho and washi papers, Chinese xuan papers and high end machine-made papers like Somerset white and Arches.
  • Handmade papers including most decorative papers, Ingres papers, Japanese paper and tissues, all characterized by lack of grain direction.

Other surfaces that can be used for printing, bookmaking and collage include:

  • Industrial papers including cigarette paper, grease and waterproof paper, toilet tissue, sandpaper, emery paper, fish paper (vulcanized fibres for electrical insulation), litmus paper, universal indicator paper, paper chromatography, and filter paper.
  • Wrapping papers for the protection of goods and merchandise. This includes wax and kraft papers, glossy gold and silver papers, corrugated box paper, brown paper, paper bag, envelopes, paper string.
  • Construction papers: papier-mâché, origami, paper planes, quilling, paper honeycomb, used as a core material in composite materials, paper engineering, construction paper and paper clothing
  • Wallpaper
  • Sellotape and masking tape
  • Foil like aluminium and other types of be pained on and distressed
  • Cards and cardboard: Card and paper stock for crafts use comes in a wide variety of textures and colors.
  • Canvases, linen and wove paper
  • Plastic sheets: drypoint sheets, OHP slides
  • Cleaning papers: toilet paper, handkerchiefs, paper towels, facial tissue and cat litter.

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Banana paper
Leather paper
Mummy paper
Oak Tag Paper
Tyvek paper

Key considerations

Paper is usually described by its size, weight, finish and stability. The kind of stock you choose will be informed by the nature of the job you’re doing.

Paper sizes

Weight, bulk and thickness

weight: Expressed in grammes per square metre (g/m2 or usually just g) of the paper. 50g is very light. Printing paper is generally between 60g and 120g. Standard photocopying paper is usually 80gsm. Anything heavier than 160 g is considered card. 240g upwards are heavy papers. A brochure would have
pages of 100 or 130gsm and a cover of 250 or 350gsm.

In the United States, the weight assigned to a paper is the weight of a ream, 500 sheets, of varying “basic sizes”, before the paper is cut into the size it is sold to end customers. For example, a ream of 20 lb, 8.5 in × 11 in (216 mm × 279 mm) paper weighs 5 pounds, because it has been cut from a larger sheet into four pieces.In the United States, printing paper is generally 20 lb, 24 lb, or 32 lb at most. Cover stock is generally 68 lb, and 110 lb or more is considered card stock.

bulk: The thickness of paper is often measured by caliper, which is typically given in thousandths of an inch in the United States and in thousandths of a mm in the rest of the world. Paper may be between 0.07 and 0.18 millimetres (0.0028 and 0.0071 in) thick.

Surface characteristics

Textured finishes, watermarks and wire patterns imitating hand-made laid paper can be created by the use of appropriate rollers in the later stages of the machine.

Wove paper does not exhibitHandmade paper similarly exhibits “deckle edges”, or rough and feathery borders.

grain  

The fibres in the paper run in the machine direction. Sheets are usually cut “long-grain”, i.e. with the grain parallel to the longer dimension of the sheet.

‘laidlines’  

“Laidlines” are small regular lines left behind on paper when it was handmade in a mould made from rows of metal wires or bamboo. Laidlines are very close together. They run perpendicular to the “chainlines”, which are further apart.

All paper produced by paper machines as the Fourdrinier Machine are wove paper, i.e. the wire mesh that transports the web leaves a pattern that has the same density along the paper grain and across the grain.

texture

cold-pressed, hot-pressed, handmade

opacity

linked to weight. tissue paper vs very thick papers.

finish: paper can be finished in many different ways; for example, gloss paper is highly finished with a shiny texture, silk paper is smooth. If you want a totally matt paper (often used for forms as it is easier to write on and for an ‘arty’ finish) you would probably use a cartridge paper.

surface coating

Coated paper has a thin layer of material such as calcium carbonate or china clay applied to one or both sides in order to create a surface more suitable for high-resolution halftone screens. (Uncoated papers are rarely suitable for screens above 150 lpi.)

Coated or uncoated papers may have their surfaces polished by calendering.

Coated papers are divided into matte, semi-matte or silk, and gloss. Gloss papers give the highest optical density in the printed image.

colour

Paper can be dyed to any colour, but professional printing is always done on white stock.

absorbency

affects spread of ink and effects of using water-based effects. linked to sizing and coating.

Stability over time

is affected by:

pHvalue: acidity/alkalinity:   

  • wood pulp paper: Alum (a variety of aluminium sulfate salts) was added in significant amounts to early wood pulp paper to assist in sizing – making it somewhat water resistant so that inks did not “run” or spread uncontrollably. However the cellulose fibres that make up paper are hydrolyzed by acid and eventually degrade until the paper disintegrated in a process that has come to be known as “slow fire”.
  • rag paper: documents written on rag paper were significantly more stable.
  • The use of non-acidic additives to make paper is becoming more prevalent, and the stability of these papers is less of an issue.

lignin/bleach

Paper made from mechanical pulp contains significant amounts of lignin, a major component in wood. In the presence of light and oxygen, lignin reacts to give yellow materials, which is why newsprint and other mechanical paper yellows with age.

Paper made from bleached kraft or sulfite pulps does not contain significant amounts of lignin and is therefore better suited for books, documents and other applications where whiteness of the paper is essential.

Paper made from wood pulp is not necessarily less durable than a rag paper. The ageing behavior of a paper is determined by its manufacture, not the original source of the fibres. Furthermore, tests sponsored by the Library of Congress prove that all paper is at risk of acid decay, because cellulose itself produces formic, acetic, lactic and oxalic acids.

When sending to a commercial printer you need to check paper quality – the weight and finish of the paper – with your client. Most printers can give you a swatch of the papers they recommend for you to share with your client and keep for future reference.

 

 

 

Papermaking: industrial

Sustainable industrial production

Stage 1: Raw materials

rags

wood: hard woods are more stable than sort woods.

Recycled fibre:.

  • Mill broke or internal mill waste: this incorporates any substandard or grade-change paper made within the paper mill itself, which then goes back into the manufacturing system to be re-pulped back into paper. Such out-of-specification paper is not sold and is therefore often not classified as genuine reclaimed recycled fibre, however most paper mills have been reusing their own waste fibre for many years, long before recycling become popular.
  • Preconsumer waste:  offcut and processing waste, such as guillotine trims and envelope blank waste; it is generated outside the paper mill and could potentially go to landfill, and is a genuine recycled fibre source; it includes de-inked preconsumer (recycled material that has been printed but did not reach its intended end use, such as waste from printers and unsold publications).[9]
  • Postconsumer waste: fibre from paper that has been used for its intended end use and includes office waste, magazine papers and newsprint. As the vast majority of this material has been printed – either digitally or by more conventional means such as lithography or rotogravure – it will either be recycled as printed paper or go through a de-inking process first.
    Recycled papers can be made from 100% recycled materials or blended with virgin pulp, although they are (generally) not as strong nor as bright as papers made from the latter.

Stage 2: Pulping

Chemical pulping

Main Wikipedia articles: kraft process, sulfite process and soda pulping

To make pulp from wood, a chemical pulping process separates lignin from cellulose fibres. This is accomplished by dissolving lignin in a cooking liquor, so that it may be washed from the cellulose; this preserves the length of the cellulose fibres. Paper made from chemical pulps are also known as wood-free papers–not to be confused with tree-free paper; this is because they do not contain lignin, which deteriorates over time. The pulp can also be bleached to produce white paper, but this consumes 5% of the fibres; chemical pulping processes are not used to make paper made from cotton, which is already 90% cellulose.

The microscopic structure of paper: Micrograph of paper autofluorescing under ultraviolet illumination. The individual fibres in this sample are around 10 µm in diameter.

There are three main chemical pulping processes:

  • sulfite process: dates back to the 1840s and it was the dominant method extent before the second world war.
  • kraft process: invented in the 1870s and first used in the 1890s, is now the most commonly practised strategy/ One of its advantages is the chemical reaction with lignin, that produces heat, which can be used to run a generator. Most pulping operations using the kraft process are net contributors to the electricity grid or use the electricity to run an adjacent paper mill. Another advantage is that this process recovers and reuses all inorganic chemical reagents.
  • soda pulping: is another specialty process used to pulp straws, bagasse and hardwoods with high silicate content.

Mechanical pulping

Mechanical pulping does not remove the lignin, so the yield is very high, >95%, however it causes the paper thus produced to turn yellow and become brittle over time. Mechanical pulps have rather short fibres, thus producing weak paper. Although large amounts of electrical energy are required to produce mechanical pulp, it costs less than the chemical kind. There are two major mechanical pulps,

  • thermomechanical pulp (TMP): wood is chipped and then fed into large steam heated refiners, where the chips are squeezed and converted to fibres between two steel discs.
  • groundwood pulp (GWP): debarked logs are fed into grinders where they are pressed against rotating stones to be made into fibres.

De-inked pulp
Main Wikipedia article: de-inking

Paper recycling processes can use either chemically or mechanically produced pulp; by mixing it with water and applying mechanical action the hydrogen bonds in the paper can be broken and fibres separated again. Most recycled paper contains a proportion of virgin fibre for the sake of quality; generally speaking, de-inked pulp is of the same quality or lower than the collected paper it was made from.

Stage 3: Additives: sizing etc

Besides the fibres, pulps may contain fillers such as:

  • chalk or china clay, which improve its characteristics for printing or writing.
  • additives for sizing purposes may be mixed with it and/or applied to the paper web later in the manufacturing process; the purpose of such sizing is to establish the correct level of surface absorbency to suit ink or paint.

Stage 4: Producing paper: pressing and drying

Main Wikipedia articles: Paper machine and papermaking

The pulp is fed to a paper machine where it is formed as a paper web and the water is removed from it by pressing and drying.

Pressing the sheet removes the water by force; once the water is forced from the sheet, a special kind of felt, which is not to be confused with the traditional one, is used to collect the water; whereas when making paper by hand, a blotter sheet is used instead.

Drying involves using air and/or heat to remove water from the paper sheets; in the earliest days of paper making this was done by hanging the sheets like laundry; in more modern times various forms of heated drying mechanisms are used. On the paper machine the most common is the steam heated can dryer. These can reach temperatures above 200 °F (93 °C) and are used in long sequences of more than 40 cans; where the heat produced by these can easily dry the paper to less than 6% moisture.

Stage 5: Finishing: coating, reeling and cutting

The paper may then undergo sizing and coating to alter its physical properties for use in various applications.

The paper is then fed onto reels if it is to be used on web printing presses, or cut into sheets for other printing processes or other purposes.

Traditional process from Europe

Industrial paper production in India

History of paper

Source: edited and expanded from Wikipedia

The word “paper” is etymologically derived from papyros, Ancient Greek for the Cyperus papyrus plant. Papyrus is a thick, paper-like material produced from the pith of the Cyperus papyrus plant which was used in ancient Egypt and other Mediterranean cultures for writing long before the making of paper in China. Papyrus however are plants dried and woven, while paper is manufactured from fibers whose properties have been changed by maceration or disintegration.

Paper, being made from wood or rags, could be produced anywhere, and once large scale production techniques had been developed it could be manufactured in almost any quantity at moderate cost. Other paper-like materials in use, including parchment, palm leaves, and vellum, were derived from materials which were expensive or in limited supply, or required extensive hand-processing to produce a satisfactory finish.

China and Japan

During the Shang (1600–1050 BC) and Zhou (1050-256 BC) dynasties of ancient China, documents were ordinarily written on bone or bamboo (on tablets or on bamboo strips sewn and rolled together into scrolls), making them very heavy, awkward, and hard to transport. The light material of silk was sometimes used as a recording medium, but was normally too expensive to consider.

Paper was invented in central China during the Han dynasty (206 BC – 220 AD). The Han dynasty Chinese court official Cai Lun (ca. 50–121) is widely regarded as the inventor of the modern method of papermaking from rags and other plant fibers. Inspired by wasps and bees he is said to have created a sheet of paper using mulberry and other bast fibres along with fishnets, old rags, and hemp waste. He submitted the process to the emperor in the first year of Yuan-Hsing (105 AD) and received praise for his ability. However, the earliest piece of paper found, at Fangmatan tomb site in Gansu province in 2006 inscribed with a map, dates from 179-41 BC, indicating that paper was in use by the military earlier than this. It is likely therefore that Cai Lun’s contribution was to improve this skill systematically and scientifically, fix a recipe for papermaking. From this time, paper has been in use everywhere and is universally called the paper of Marquis Tshai.

In ancient China, the mortar and pestle method was primarily used for papermaking. The manufacture may have originated from the practice of pounding and stirring rags in water, after which the matted fibres were collected on a mat. The bark of Paper Mulberry was particularly valued and high quality paper was developed in the late Han period, which used the bark of tan (檀; sandalwood). In the Eastern Jin period paper began to be made on a fine bamboo screen-mould, treated with insecticidal dye for permanence. After printing became popular in the Song dynasty the demand grew more. Paper was often used as a levy, with one prefecture sending some 1.5 million sheets of paper to the capital as tribute up to the year 1101.

Paper had a wide range of uses:

  • wrapping or padding protection : from the 2nd century BC it was used for padding for delicate bronze mirrors,  padding of poisonous ‘medicine’.
  • toilet paper was used in China from around 875 C.E.
  • During the Tang dynasty (618–907) paper was folded and sewn into square bags to preserve the flavor of tea. During the same period, it was written that tea was served from baskets with multi-colored paper cups and paper napkins of different size and shape.
  • paper-printed money: the world’s first known paper-printed money, or banknote was produced by the government during the Song dynasty (960–1279).
  • paper envelopes:  paper money bestowed as gifts to deserving government officials were wrapped in special paper envelopes as early as the Song dynasty (960–1279).
  • books: the world’s earliest known printed book (using woodblock printing), the Diamond Sutra of 868, shows the widespread availability and practicality of paper in China.

After its origin in central China, the production and use of paper spread steadily. It is clear that paper was used at Dunhuang by AD 150, in Loulan in the modern-day province of Xinjiang by 200, and in Turpan by 399.

Paper was concurrently introduced in Japan sometime between the years 280 and 610.

Islamic world and South Asia

Paper spread slowly to the Muslim world to the west via the Silk Road. The legend goes, the secret of papermaking was obtained from two Chinese prisoners from the Battle of Talas as a result of the tradition that Muslims would release their prisoners if they could teach ten Muslims any valuable knowledge. There are records of paper being made at Gilgit in Pakistan by the sixth century, in Samarkand in modern-day Uzbekistan by 751, in Baghdad by 793, in Egypt by 900, and in Fes, Morocco around 1100. Paper manufacture was introduced to India in the 13th century by Muslim merchants, where it almost wholly replaced traditional writing materials.

The Muslim world improved upon papermaking with the use of human/animal-powered papermills and trip hammers. The laborious process of paper making was refined and machinery was designed for bulk manufacturing of paper. Production began in Baghdad, where a method was invented to make a thicker sheet of paper, which helped transform papermaking from an art into a major industry. The use of water-powered pulp mills for preparing the pulp material used in papermaking, dates back to Samarkand in the 8th century, though this should not be confused with paper mills (see Paper mills section below). Trip hammers (human- or animal-powered) replaced the traditional Chinese mortar and pestle method and was then later employed by the Chinese. Following the First Crusade in 1096, paper manufacturing in Damascus was interrupted by wars, but Egypt continued to produce thicker paper, while Iran became the center of the thinner papers.

Books: By the 9th century, Muslims were using paper regularly, although for important works like copies of the revered Qur’an, vellum was still preferred. Advances in book production and bookbinding were introduced. As paper was less reactive to humidity, the heavy boards were not needed making books lighter—sewn with silk and bound with leather-covered paste boards; they had a flap that wrapped the book up when not in use.  By the 12th century in Marrakech in Morocco a street was named “Kutubiyyin” or book sellers which contained more than 100 bookshops.

The earliest recorded use of paper for packaging dates back to 1035, when a Persian traveller visiting markets in Cairo noted that vegetables, spices and hardware were wrapped in paper for the customers after they were sold.

Europe

Papermaking and manufacturing in Europe was started by Muslims living on the Iberian Peninsula (today’s Portugal and Spain) and Sicily in the 10th century, and slowly spread to Italy and Southern France, reaching Germany by 1400 and Scandinavia by 1596. The rapid expansion of European paper production was promoted by the invention of the printing press as part of the beginning of the Printing Revolution in the 15th century.

  • Spain: Papermaking reached Europe as early as 1085 in Toledo. The oldest known paper document in the West is the Mozarab Missal of Silos from the 11th century, probably using paper made in the Islamic part of the Iberian Peninsula. They used hemp and linen rags as a source of fiber. The first recorded paper mill in the Iberian Peninsula was in Xàtiva in 1151.
  • France: had a paper mill by 1190
  • Italy:  1276 mills were established in Fabriano, Italy and in Treviso and other northern Italian towns by 1340. Papermaking then spread further northwards, with evidence of paper being made in Troyes, France by 1348
  • Holland: sometime around 1340–1350 spreading to Netherlands by 1586.
  • Germany: Mainz, in 1320, and in Nuremberg by 1390 in a mill set up by Ulman Stromer. This was just about the time when the woodcut printmaking technique was transferred from fabric to paper in the old master print and popular prints.
  • Switzerland by 1432
  • England  the first mill was set up by John Tate in 1490 near Stevenage in Hertfordshire, but the first commercially successful paper mill in Britain did not occur before 1588 when John Spilman set up a mill near Dartford in Kent.
  • Poland by 1491
  • Austria by 1498
  • Russia by 1576
  • Scandinavia: Denmark by 1596, and to Sweden by 1612.

Papermaking was mechanized by the use of waterpower. A paper mill is a water-powered mill that pounds the pulp by the use of trip-hammers. The mechanization of the pounding process was an important improvement in paper manufacture over the manual pounding with hand pestles. The first water papermills were built in the Iberian Peninsula:  1282 in the Spanish Kingdom of Aragon and 1411 in the Portuguese city of Leiria. Due to their noise and smell, paper mills were required by medieval law to be erected outside of the city perimeter.

Paper making centers began to multiply in the late 13th century in Italy, reducing the price of paper to one sixth of parchment and then falling further; paper making centers reached Germany a century later. From the mid-14th century onwards, European paper milling underwent a rapid improvement of many other work processes.

Fabriano papermakers: Fabriano artisans were introduced to the technique of making paper by Arab prisoners who settled in a town called Borgo_Saraceno. At the time they were renowned for their wool-weaving and manufacture of cloth. Fabriano papermakers considered the process of making paper by hand an art form and were able to refine the process to successfully compete with parchment which was the primary medium for writing at the time. They developed the application of stamping hammers to reduce rags to pulp through adapting the water wheels from the fuller’s mills, raising the hammers through fixing cams to an axle made from a large tree trunk to drive a series of 3 wooden hammers per trough. They developed sizing by means of animal glue, obtained by boiling scrolls or scraps of animal skin to size the paper; it is suggested that this technique was recommended by the local tanneries. They introduced the first European watermarks by applying metal wires on a cover laid against the mould which was used for forming the paper.

Before the industrialisation of the paper production the most common fibre source was recycled fibres from used textiles, called rags. The rags were from hemp, linen and cotton. A process for removing printing inks from recycled paper was invented by German jurist Justus Claproth in 1774. Today this method is called deinking.

America

In America, archaeological evidence indicates that a  bark-paper writing material called amatl was used by the Mayans by the 5th century AD and in widespread use among Mesoamerican cultures until the Spanish conquest. The paper is created by boiling and pounding the inner bark of trees, until the material becomes suitable for art and writing. European paper making methods spread to the American continent first in Mexico by 1575 and then in Philadelphia by 1690.

19th century advances in papermaking

Although cheaper than vellum, paper remained expensive, at least in book-sized quantities. A number of advances in 19th Century significantly reduced cost:

steam-driven paper making machines which could make paper with fibres from wood pulp. Although older machines predated it, the Fourdrinier papermaking machine became the basis for most modern papermaking. Nicholas Louis Robert of Essonnes, France, was granted a patent for a continuous paper making machine in 1799. Gamble was granted British patent 2487 on 20 October 1801. An improved version of the Robert original was installed at Frogmore, Hertfordshire, in 1803, followed by another in 1804. A third machine was installed at the Fourdriniers’ own mill at Two Waters. The Fourdriniers also bought a mill at St Neots intending to install two machines there and the process and machines continued to develop.

 introduction of wood pulp 1843 as alternative to rags from ragpickers. By 1800, Matthias Koops (in London, England) further investigated the idea of using wood to make paper, and in 1801 he wrote and published a book printed on paper made from wood shavings (and adhered together). Then in the 1830s and 1840s, Friedrich Gottlob Keller and Charles Fenerty independently from each other began experiments with wood but using the same technique used in paper making; instead of pulping rags, they thought about pulping wood. They invented a machine which extracted the fibres from wood (exactly as with rags) and made paper from it. Charles Fenerty also bleached the pulp so that the paper was white.

This started a new era for paper making. By the end of the 19th-century almost all printers in the western world were using wood in lieu of rags to make paper. Together with the invention of the practical fountain pen, the mass-produced pencil and the advent of the steam driven rotary printing press, wood based paper caused a major transformation of the 19th century economy and society in industrialized countries. With the introduction of cheaper paper, schoolbooks, fiction, non-fiction, and newspapers became gradually available by 1900. Cheap wood based paper also meant that keeping personal diaries or writing letters became possible and so, by 1850, the clerk, or writer, ceased to be a high-status job.

Acid-free paper: However the original wood-based paper was acidic due to the use of alum and more prone to disintegrate over time, through processes known as slow fires. Documents written on more expensive rag paper were more stable. Book publishers use acid-free rag paper for hardback and trade paperback books.

 

 

 

 

Paper Sizes

ISO 216 metric sizes  are the standard for Europe and most of the world outside the US. The ISO 216 system is based on the surface area of a sheet of paper, not on a sheet’s width and length. It was first adopted in Germany in 1922 and generally spread as nations adopted the metric system.

  • A sizes describe paper.
  • B sizes are larger and used for printing as they include a trim and
  • C sizes are for envelopes to contain the A sizes.

In the ISO paper size system all sheet sizes have a width to height ratio of the square root of two (1:1.4142). By placing two sheets of A series paper next to each other, or by cutting one in half parallel to its shorter side, the resulting sheet will again have the same width to height ratio. The largest standard size paper is A0 (A zero), measuring one square meter (approx. 1189 × 841 mm). Two sheets of A1, placed upright side by side fit exactly into one sheet of A0 laid on its side. Similarly, two sheets of A2 fit into one sheet of A1 and so forth. Common sizes used in the office and the home are A4 and A3 (A3 is the size of two A4 sheets). In papers for printing, the prefix R or SR is added to the A size to denote a slightly larger sheet to allow for machine grip and registration in the print process eg for full bleed images.

papersizes

 

Size Height x Width (mm) Height x Width (in)
4A0 2378 x 1682 mm 93.6 x 66.2 in
2A0 1682 x 1189 mm 66.2 x 46.8 in
A0 1189 x 841 mm 46.8 x 33.1 in
A1 841 x 594 mm 33.1 x 23.4 in
A2 594 x 420 mm 23.4 x 16.5 in
A3 420 x 297 mm 16.5 x 11.7 in
A4 297 x 210 mm 11.7 x 8.3 in
A5 210 x 148 mm 8.3 x 5.8 in
A6 148 x 105 mm 5.8 x 4.1 in
A7 105 x 74 mm 4.1 x. 2.9 in
A8 74 x 52 mm 2.9 x 2.0 in
A9 52 x 37 mm 2.0 x 1.5 in
A10 37 x 26 mm 1.5 x 1.0 in

 

In UK imperial measurements are still used alongside the metric system, including terms like Foolscap, Crown and Demy.

Most commercial paper sold in North America is cut to standard paper sizes based on customary units and is defined by the length and width of a sheet of paper.