Paper is thin material mainly used for writing upon, printing upon or packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets.
The earliest recorded forms of paper were in use in Egypt in around 3500 BC, made from the papyrus plant. True paper is believed to have originated in China in approximately the 2nd century AD, although there is some evidence for it being used before this date. China used paper as an effective and cheap alternative to silk. The use of paper spread from China through the Islamic world, and entered production in Europe in the early 12th century.
In America, archaeological evidence indicates that a similar parchment writing material was invented by the Mayans no later than the 5th century AD. Called amatl, it was in widespread use among Mesoamerican cultures until the Spanish conquest. The parchment is created by boiling and pounding the inner bark of trees, until the material becomes suitable for art and writing.
Together with the invention of the fountain pen and the mass produced pencil of the same period, and in conjunction with the advent of the steam driven rotary printing press, wood based paper caused a major transformation of 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.
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. Mass-market paperback books still use these cheaper mechanical papers, but book publishers can now use acid-free paper for hardback and trade paperback books.
Although paper had been known as a wrapping and padding material, the first use of toilet paper in human history dates back to the 6th century AD, in early medieval China. During the Ming Dynasty, it was recorded that 720,000 sheets of toilet paper two by three feet in size were produced for the general use of the Imperial court at the capital of Nanjing. It was also recorded that for Emperor Hongwu’s imperial family alone, there were 15,000 sheets of special soft-fabric toilet paper made, and each sheet of toilet paper was perfumed.
The standard 8.5″ x 11″ size stems from the original size of a vat that was used to make paper. At the time, paper was made from passing a fiber and water slurry through a screen at the bottom of a box. The box was 17″ deep and 44″ wide. That sheet, folded in half in the long direction, then twice in the opposite direction, made a sheet of paper that was exactly 8.5″ x 11″.