In 1490 one writer bet that parchment would outlast printed paper by centuries
In 1490 Johannes Trithemius confidently argued that handwriting on parchment would survive a thousand years, while printing on paper might manage two hundred at best. He underestimated paper badly. Good sheets from his era have lasted 500 years or more in decent libraries, and parchment was already losing its hold on books.
Parchment is animal skin, usually from sheep, calves or goats, that has been cleaned and dried under tension rather than tanned. The hide was soaked, then left in a bath, originally of fermented vegetable matter and later of lime, for eight days or more, longer in winter, until the hair loosened. Stretched on a frame, it was scraped with a curved blade to the right thickness. Because the skin is nearly all collagen, it glues itself into shape as it dries. Pumice smoothed the surface, and pastes of lime, flour, egg white and milk whitened it.
The name comes from Pergamon, a Hellenistic city so dominant in the trade that Pliny the Elder claimed it invented parchment when rival Alexandria cornered papyrus. The story is almost certainly false. Egyptian leather documents survive from about the 24th century BC, and Herodotus noted that Ionians simply called books skins. By the fourth century AD important texts in papyrus-using cultures were being copied onto parchment, which endured far better.
Vellum was the premium grade, from calfskin, and uterine vellum finer still. Many assumed it came from unborn calves, but analysis of 13th-century pocket Bibles suggests a lost technique rather than fetal hides. The terms blurred so much that Hamlet asks Horatio whether parchment is made of sheepskins and gets told calves' too. Scribes reused sheets as well: between the 7th and 9th centuries older manuscripts were scrubbed and rewritten, and these palimpsests often still show the first text. Parchment's sensitivity to humidity also explains the heavy wooden boards and brass clasps on old books, which kept pages from buckling.
Cheap rag paper and then printing displaced it in the 15th century; only 12 of the 48 surviving Gutenberg Bibles are on parchment. Yet it lingers. Torah scrolls, tefillin and mezuzahs must still be written on kosher animal hide, British Acts of Parliament were printed on vellum until 2015, and Heriot-Watt University still issues degrees on goatskin.
Source: Parchment
