Parchment

Parchment is a material made from processed animal skin and used—mainly in the past—for writing on.

Parchment is most commonly made of calfskin, sheepskin, or goatskin. It was historically used for writing documents, notes, or the pages of a book. Parchment is limed, scraped and dried under tension. It is not tanned, and is thus different from leather. This makes it more suitable for writing on, but leaves it very reactive to changes in relative humidity and makes it revert to rawhide if overly wet.

It may be called animal membrane by libraries and museums that wish to avoid distinguishing between "parchment" and the more restricted term "vellum" (see below).

Today the term "parchment" is often used in non-technical contexts to refer to any animal skin, particularly goat, sheep or cow, that has been scraped or dried under tension. Vellum (from the Old French velin or vellin, and ultimately from the Latin vitulus, meaning a calf) in theory refers exclusively to calfskin, and is used to denote a finer quality of material, the finest being "uterine vellum", taken from a calf foetus.

The term "parchment" originally referred only to the skin of sheep and, occasionally, goats. It is said to be only in relatively modern times that confusion between the terms has arisen: traditionally the distinction was more strictly observed, for example by lexicographer Samuel Johnson in 1755, and by master calligrapher Edward Johnston in 1906. However, when old books and documents are encountered it may be difficult, without scientific analysis, to determine the precise animal origin of a skin in terms of its species, let alone the age of the animal; and for this reason many conservators, librarians and archivists prefer to use either the broader term "parchment", or the neutral term "animal membrane".

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