Papermaking

Papermaking is the process of manufacturing paper and cardboard, which are widely used for printing, writing, and packaging, and numerous other purposes. Today almost all paper is made using industrial machinery, while handmade paper survives as a specialized craft and a medium for artistic expression.

In papermaking, a dilute suspension consisting mostly of separate cellulose fibres in water is drained through a sieve-like screen, so that a mat of randomly interwoven fibres is laid down. Water is further removed from this sheet by pressing, sometimes aided by suction or vacuum, or heating. Once dry, a generally flat, uniform and strong sheet of paper is achieved.

Before the invention and current widespread adoption of automated machinery, all paper was made by hand, formed or laid one sheet at a time by specialized laborers. Even today those who make paper by hand use tools and technologies quite similar to those existing hundreds of years ago, as originally developed in China and other regions of Asia, or those further modified in Europe. Handmade paper is still appreciated for its distinctive uniqueness and the skilled craft involved in making each sheet, in contrast with the higher degree of uniformity and perfection at lower prices achieved among industrial products.

The word "paper" is etymologically derived from papyrus, 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 societies for writing long before paper was used in China. Papyrus is prepared by cutting off thin ribbon-like strips of the pith (interior) of the Cyperus papyrus plant and then laying out the strips side-by-side to make a sheet. A second layer is then placed on top, with the strips running perpendicular to the first. The two layers are then pounded together using a mallet to make a sheet. The result is very strong, but has an uneven surface, especially at the edges of the strips. When used in scrolls, repeated rolling and unrolling causes the strips to come apart again, typically along vertical lines. This effect can be seen in many ancient papyrus documents.

Hemp paper had been used in China for wrapping and padding since the eighth century BC. Paper with legible Chinese writings on it has been dated to 8 BC. The traditional inventor attribution is of Cai Lun, an official attached to the Imperial court during the Han dynasty (202 BC – 220 CE), said to have invented paper about 105 CE using mulberry and other bast fibres along with fishnets, old rags, and hemp waste. Paper used as a writing medium had become widespread by the 3rd century and, by the 6th century, toilet paper was starting to be used in China as well. During the Tang dynasty (618–907 CE) paper was folded and sewn into square bags to preserve the flavour of tea, while the later Song dynasty (960–1279 CE) was the first government to issue paper-printed money.

In the 8th century, papermaking spread to the Islamic world, where the process was refined, and machinery was designed for bulk manufacturing. Production began in Samarkand, Baghdad, Damascus, Cairo, Morocco, and then Muslim Spain. In Baghdad, papermaking was under the supervision of the Grand Vizier Ja'far ibn Yahya. Muslims invented a method to make a thicker sheet of paper. This innovation helped transform papermaking from an art into a major industry. The earliest use of water-powered mills in paper production, specifically the use of pulp mills for preparing the pulp for papermaking, dates back to Samarkand in the 8th century. The earliest references to paper mills also come from the medieval Islamic world, where they were first noted in the 9th century by Arabic geographers in Damascus.

Traditional papermaking in Asia uses the inner bark fibers of plants. This fiber is soaked, cooked, rinsed and traditionally hand-beaten to form the paper pulp. The long fibers are layered to form strong, translucent sheets of paper. In Eastern Asia, three traditional fibers are abaca, kōzo and gampi. In the Himalayas, paper is made from the lokta plant. This paper is used for calligraphy, printing, book arts, and three-dimensional work, including origami.

In Europe, papermaking moulds using metallic wire were developed, and features like the watermark were well established by 1300 CE, while hemp and linen rags were the main source of pulp, cotton eventually taking over after Southern plantations made that product in large quantities. Papermaking was originally not popular in Europe due to not having many advantages over papyrus and parchment. It was not until the 15th century with the invention of the movable type of printing and its demand for paper that many paper mills entered production, and papermaking became an industry.