Kurlansky, Mark. Paper. New York: W. W. Norton, 2016. ISBN 978-0-393-23961-4.
One of the things that makes us human is our use of extrasomatic memory: we invent ways to store and retrieve things outside our own brains. It's as if when the evolutionary drive which caused the brains of our ancestors to grow over time reached its limit, due to the physical constraints of the birth canal, we applied the cleverness of our bulging brains to figure out not only how to record things for ourselves, but to pass them on to other individuals and transmit them through time to our successors.

This urge to leave a mark on our surroundings is deeply-seated and as old as our species. Paintings at the El Castillo site in Spain have been dated to at least 40,800 years before the present. Complex paintings of animals and humans in the Lascaux Caves in France, dated around 17,300 years ago, seem strikingly modern to observers today. As anybody who has observed young children knows, humans do not need to be taught to draw: the challenge is teaching them to draw only where appropriate.

Nobody knows for sure when humans began to speak, but evidence suggests that verbal communication is at least as old and possibly appeared well before the first evidence of drawing. Once speech appeared, it was not only possible to transmit information from one human to another directly but, by memorising stories, poetry, and songs, to create an oral tradition passed on from one generation to the next. No longer what one individual learned in their life need die with them.

Given the human compulsion to communicate, and how long we've been doing it by speaking, drawing, singing, and sculpting, it's curious we only seem to have invented written language around 5000 years ago. (But recall that the archaeological record is incomplete and consists only of objects which survived through the ages. Evidence of early writing is from peoples who wrote on durable material such as stone or clay tablets, or lived in dry climates such as that of Egypt where more fragile media such as papyrus or parchment would be preserved. It is entirely possible writing was invented much earlier by any number of societies who wrote on more perishable surfaces and lived in climates where they would not endure.)

Once writing appeared, it remained the province of a small class of scribes and clerics who would read texts to the common people. Mass literacy did not appear for millennia, and would require a better medium for the written word and a less time-consuming and costly way to reproduce it. It was in China that the solutions to both of these problems would originate.

Legends date Chinese writing from much earlier, but the oldest known writing in China is dated around 3300 years ago, and was inscribed on bones and turtle shells. Already, the Chinese language used six hundred characters, and this number would only increase over time, with a phonetic alphabet never being adopted. The Chinese may not have invented bureaucracy, but as an ancient and largely stable society they became very skilled at it, and consequently produced ever more written records. These writings employed a variety of materials: stone, bamboo, and wood tablets; bronze vessels; and silk. All of these were difficult to produce, expensive, and many required special skills on the part of scribes.

Cellulose is a main component of the cell wall of plants, and forms the structure of many of the more complex members of the plant kingdom. It forms linear polymers which produce strong fibres. The cellulose content of plants varies widely: cotton is 90% cellulose, while wood is around half cellulose, depending on the species of tree. Sometime around A.D. 100, somebody in China (according to legend, a courtier named Cai Lun) discovered that through a process of cooking, hammering, and chopping, the cellulose fibres in material such as discarded cloth, hemp, and tree bark could be made to separate into a thin slurry of fibres suspended in water. If a frame containing a fine screen were dipped into a vat of this material, rocked back and forth in just the right way, then removed, a fine layer of fibres with random orientation would remain on the screen after the water drained away. This sheet could then be removed, pressed, and dried, yielding a strong, flat material composed of intertwined cellulose fibres. Paper had been invented.

Paper was found to be ideal for writing the Chinese language, which was, and is today, usually written with a brush. Since paper could be made from raw materials previously considered waste (rags, old ropes and fishing nets, rice and bamboo straw), water, and a vat and frame which were easily constructed, it was inexpensive and could be produced in quantity. Further, the papermaker could vary the thickness of the paper by adding more or less pulp to the vat, by the technique in dipping the frame, and produce paper with different surface properties by adding “sizing” material such as starch to the mix. In addition to sating the appetite of the imperial administration, paper was adopted as the medium of choice for artists, calligraphers, and makers of fans, lanterns, kites, and other objects.

Many technologies were invented independently by different societies around the world. Paper, however, appears to have been discovered only once in the eastern hemisphere, in China, and then diffused westward along the Silk Road. The civilisations of Mesoamerica such as the Mayans, Toltecs, and Aztecs, extensively used, prior to the Spanish conquest, what was described as paper, but it is not clear whether this was true paper or a material made from reeds and bark. So thoroughly did the conquistadors obliterate the indigenous civilisations, burning thousands of books, that only three Mayan books and fifteen Aztec documents are known to have survived, and none of these are written on true paper.

Paper arrived in the Near East just as the Islamic civilisation was consolidating after its first wave of conquests. Now faced with administering an empire, the caliphs discovered, like the Chinese before them, that many documents were required and the new innovative writing material met the need. Paper making requires a source of cellulose-rich material and abundant water, neither of which are found in the Arabian peninsula, so the first great Islamic paper mill was founded in Baghdad in A.D. 794, originally employing workers from China. It was the first water-powered paper mill, a design which would dominate paper making until the age of steam. The demand for paper continued to grow, and paper mills were established in Damascus and Cairo, each known for the particular style of paper they produced.

It was the Muslim invaders of Spain who brought paper to Europe, and paper produced by mills they established in the land they named al-Andalus found markets in the territories we now call Italy and France. Many Muslim scholars of the era occupied themselves producing editions of the works of Greek and Roman antiquity, and wrote them on paper. After the Christian reconquest of the Iberian peninsula, papermaking spread to Italy, arriving in time for the awakening of intellectual life which would be called the Renaissance and produce large quantities of books, sheet music, maps, and art: most of it on paper. Demand outstripped supply, and paper mills sprung up wherever a source of fibre and running water was available.

Paper provided an inexpensive, durable, and portable means of storing, transmitting, and distributing information of all kinds, but was limited in its audience as long as each copy had to be laboriously made by a scribe or artist (often introducing errors in the process). Once again, it was the Chinese who invented the solution. Motivated by the Buddhist religion, which values making copies of sacred texts, in the 8th century A.D. the first documents were printed in China and Japan. The first items to be printed were single pages, carved into a single wood block for the whole page, then printed onto paper in enormous quantities: tens of thousands in some cases. In the year 868, the first known dated book was printed, a volume of Buddhist prayers called the Diamond Sutra. Published on paper in the form of a scroll five metres long, each illustrated page was printed from a wood block carved with its entire contents. Such a “block book” could be produced in quantity (limited only by wear on the wood block), but the process of carving the wood was laborious, especially since text and images had to be carved as a mirror image of the printed page.

The next breakthrough also originated in China, but had limited impact there due to the nature of the written language. By carving or casting an individual block for each character, it was possible to set any text from a collection of characters, print documents, then reuse the same characters for the next job. Unfortunately, by the time the Chinese began to experiment with printing from movable type in the twelfth and thirteenth centuries, it took 60,000 different characters to print the everyday language and more than 200,000 for literary works. This made the initial investment in a set of type forbidding. The Koreans began to use movable type cast from metal in the fifteenth century and were so impressed with its flexibility and efficiency that in 1444 a royal decree abolished the use of Chinese characters in favour of a phonetic alphabet called Hangul which is still used today.

It was in Europe that movable type found a burgeoning intellectual climate ripe for its adoption, and whence it came to change the world. Johannes Gutenberg was a goldsmith, originally working with his brother Friele in Mainz, Germany. Fleeing political unrest, the brothers moved to Strasbourg, where around 1440 Johannes began experimenting with movable type for printing. His background as a goldsmith equipped him with the required skills of carving, stamping, and casting metal; indeed, many of the pioneers of movable type in Europe began their careers as goldsmiths. Gutenberg carved letters into hard metal, forming what he called a punch. The punch was used to strike a copper plate, forming an impression called the matrix. Molten lead was then poured into the matrix, producing individual characters of type. Casting letters in a matrix allowed producing as many of each letter as needed to set pages of type, and for replacement of worn type as required. The roman alphabet was ideal for movable type: while the Chinese language required 60,000 or more characters, a complete set of upper and lower case letters, numbers, and punctuation for German came to only around 100 pieces of type. Accounting for duplicates of commonly used letters, Gutenberg's first book, the famous Gutenberg Bible, used a total of 290 pieces of type. Gutenberg also developed a special ink suited for printing with metal type, and adapted a press he acquired from a paper mill to print pages.

Gutenberg was secretive about his processes, likely aware he had competition, which he did. Movable type was one of those inventions which was “in the air”—had Gutenberg not invented and publicised it, his contemporaries working in Haarlem, Bruges, Avignon, and Feltre, all reputed by people of those cities to have gotten there first, doubtless would have. But it was the impact of Gutenberg's Bible, which demonstrated that movable type could produce book-length works of quality comparable to those written by the best scribes, which established the invention in the minds of the public and inspired others to adopt the new technology.

Its adoption was, by the standards of the time, swift. An estimated eight million books were printed and sold in Europe in the second half of the fifteenth century—more books than Europe had produced in all of history before that time. Itinerant artisans would take their type punches from city to city, earning money by setting up locals in the printing business, then moving on.

In early sixteenth century Germany, the printing revolution sparked a Reformation. Martin Luther, an Augustinian monk, completed his German translation of the Bible in 1534 (he had earlier published a translation of the New Testament in 1522). This was the first widely-available translation of the Bible into a spoken language, and reinforced the Reformation idea that the Bible was directly accessible to all, without need for interpretation by clergy. Beginning with his original Ninety-five Theses, Luther authored thirty publications, which it is estimated sold 300,000 copies (in a territory of around 14 million German speakers). Around a third of all publications in Germany in the era were related to the Reformation.

This was a new media revolution. While the incumbent Church reacted at the speed of sermons read occasionally to congregations, the Reformation produced a flood of tracts, posters, books, and pamphlets written in vernacular German and aimed directly at an increasingly literate population. Luther's pamphlets became known as Flugschriften: “quick writing”. One such document, written in 1520, sold 4000 copies in three weeks and 50,000 in two years. Whatever the merits of the contending doctrines, the Reformation had fully embraced and employed the new communication technology to speak directly to the people. In modern terms, you might say the Reformation was the “killer app” for movable type printing.

Paper and printing with movable type were the communication and information storage technologies the Renaissance needed to express and distribute the work of thinkers and writers across a continent, who were now able to read and comment on each other's work and contribute to a culture that knew no borders. Interestingly, the technology of paper making was essentially unchanged from that of China a millennium and a half earlier, and printing with movable type hardly different from that invented by Gutenberg. Both would remain largely the same until the industrial revolution. What changed was an explosion in the volume of printed material and, with increasing literacy among the general public, the audience and market for it. In the eighteenth century a new innovation, the daily newspaper, appeared. Between 1712 and 1757, the circulation of newspapers in Britain grew eightfold. By 1760, newspaper circulation in Britain was 9 million, and would increase to 24 million by 1811.

All of this printing required ever increasing quantities of paper, and most paper in the West was produced from rags. Although the population was growing, their thirst for printed material expanded much quicker, and people, however fastidious, produce only so many rags. Paper shortages became so acute that newspapers limited their size based on the availability and cost of paper. There were even cases of scavengers taking clothes from the dead on battlefields to sell to paper mills making newsprint used to report the conflict. Paper mills resorted to doggerel to exhort the public to save rags:

The scraps, which you reject, unfit
To clothe the tenant of a hovel,
May shine in sentiment and wit,
And help make a charming novel…

René Antoine Ferchault de Réaumur, a French polymath who published in numerous fields of science, observed in 1719 that wasps made their nests from what amounted to paper they produced directly from wood. If humans could replicate this vespidian technology, the forests of Europe and North America could provide an essentially unlimited and renewable source of raw material for paper. This idea was to lie fallow for more than a century. Some experimenters produced small amounts of paper from wood through various processes, but it was not until 1850 that paper was manufactured from wood in commercial quantities in Germany, and 1863 that the first wood-based paper mill began operations in America.

Wood is about half cellulose, while the fibres in rags run up to 90% cellulose. The other major component of wood is lignin, a cross-linked polymer which gives it its strength and is useless for paper making. In the 1860s a process was invented where wood, first mechanically cut into small chips, was chemically treated to break down the fibrous structure in a device called a “digester”. This produced a pulp suitable for paper making, and allowed a dramatic expansion in the volume of paper produced. But the original wood-based paper still contained lignin, which turns brown over time. While this was acceptable for newspapers, it was undesirable for books and archival documents, for which rag paper remained preferred. In 1879, a German chemist invented a process to separate lignin from cellulose in wood pulp, which allowed producing paper that did not brown with age.

The processes used to make paper from wood involved soaking the wood pulp in acid to break down the fibres. Some of this acid remained in the paper, and many books printed on such paper between 1840 and 1970 are now in the process of slowly disintegrating as the acid eats away at the paper. Only around 1970 was it found that an alkali solution works just as well when processing the pulp, and since then acid-free paper has become the norm for book publishing.

Most paper is produced from wood today, and on an enormous, industrial scale. A single paper mill in China, not the largest, produces 600,000 tonnes of paper per year. And yet, for all of the mechanisation, that paper is made by the same process as the first sheet of paper produced in China: by reducing material to cellulose fibres, mixing them with water, extracting a sheet (now a continuous roll) with a screen, then pressing and drying it to produce the final product.

Paper and printing is one of those technologies which is so simple, based upon readily-available materials, and potentially revolutionary that it inspires “what if” speculation. The ancient Egyptians, Greeks, and Romans each had everything they needed—raw materials, skills, and a suitable written language—so that a Connecticut Yankee-like time traveller could have explained to artisans already working with wood and metal how to make paper, cast movable type, and set up a printing press in a matter of days. How would history have differed had one of those societies unleashed the power of the printed word?

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