The Long Journey of Paper
Few materials are as ordinary, or as easily overlooked, as paper. We write on it, wrap food in it and throw away vast quantities of it every day. Yet for most of human history, people recorded information on surfaces that were heavy, scarce or expensive: clay tablets, strips of bamboo, animal skins and woven silk. The arrival of a cheap, light and flexible alternative was one of the quiet revolutions of the ancient world, and its story spans more than two thousand years and several continents.
The craft began in China. Chinese tradition credits its invention to an official of the imperial court in the early second century CE, who is said to have presented the emperor with sheets made from tree bark, hemp, old rags and worn-out fishing nets. Archaeologists, however, have recovered fragments of paper from tombs and watchtowers that are at least two centuries older, which suggests that the official improved and standardised an existing technique rather than creating it from nothing. Interestingly, the earliest paper does not seem to have been used much for writing. Most surviving pieces were used for wrapping medicine, padding delicate objects or even making clothing, and it was only gradually that scribes came to prefer it to bamboo and silk.
The basic method changed surprisingly little over the following centuries. Plant fibres were soaked, beaten into a pulp and mixed with water in a large vat. A worker dipped a fine screen into the vat, lifted out a thin layer of fibres and allowed the water to drain away. The wet sheet was then pressed and hung up to dry. Chinese makers experimented with many raw materials, but the inner bark of the mulberry tree became especially valued, because its long fibres produced a sheet that was both thin and strong.
For several hundred years the technique remained largely within East Asia, spreading to Korea and then to Japan, where makers developed exceptionally fine papers that are still produced by hand today. Its movement westwards came later. By the eighth century paper was being made in Central Asia, and a widely repeated story claims that the skill was passed on by Chinese papermakers who had been captured in a battle. Many historians now regard this account as too neat, arguing that the knowledge more probably travelled gradually along trade routes with merchants. Whatever the truth, papermakers in the region adapted the process to local conditions: since mulberry trees were scarce, they relied instead on linen and cotton rags.
From there, papermaking spread across the Middle East and North Africa, and cities such as Baghdad and Cairo became important centres of production. Paper allowed governments to keep far more extensive records, and markets for books flourished. When the craft finally reached Europe, through Spain and Italy, it met with suspicion. Parchment, made from animal skin, was considered more durable, and in some places documents written on paper were not accepted as legally valid. Italian makers, however, transformed the industry. They harnessed water power to drive heavy hammers that beat the rags into pulp, greatly increasing output, and they began to press a faint design into each sheet while it was still wet. These watermarks identified the mill that had produced the paper, and historians now use them to date old documents.
Demand rose steeply after the introduction of the printing press in the fifteenth century, and for the next four hundred years the main limit on paper production was the supply of rags. Collectors went from door to door buying old clothing, and some governments even restricted the export of rags. By the early nineteenth century, the search for a substitute had become urgent. Inventors tried straw, grass and various other plants before settling on wood, which could be ground or chemically broken down into pulp in enormous quantities. Combined with new machines that produced paper in a continuous roll rather than sheet by sheet, wood pulp made paper cheap enough for daily newspapers and inexpensive books to reach ordinary readers.
This cheapness came at a price. Much of the paper made from wood in the nineteenth and early twentieth centuries was treated with chemicals that make it acidic, and over time it turns yellow and becomes brittle. Libraries and archives around the world now hold millions of books that are slowly crumbling on their shelves, while much older rag paper often remains in good condition. Since the late twentieth century, manufacturers have increasingly produced acid-free paper for documents that are intended to last, and conservators have developed methods of neutralising the acid in older volumes, although treating whole collections remains slow and costly. Paper, it seems, is still teaching us lessons about the balance between cost and permanence.
