Vellum

Vellum is prepared animal skin or membrane, typically used as writing material. It is often distinguished from parchment, either by being made from calfskin (rather than the skin of other animals), or simply by being of a higher quality. Vellum is prepared for writing and printing on single pages, scrolls, and codices (books).

Modern scholars and experts often prefer to use the broader term "membrane", which avoids the need to draw a distinction between vellum and parchment. It may be very hard to determine the animal species involved (let alone its age) without detailed scientific analysis.

Vellum is generally smooth and durable, but there are great variations in its texture which are affected by the way it is made and the quality of the skin. The making involves the cleaning, bleaching, stretching on a frame (a "herse"), and scraping of the skin with a crescent-shaped knife (a "lunarium" or "lunellum"). To create tension, the process goes back and forth between scraping, wetting and drying. Scratching the surface with pumice, and treating with lime or chalk to make it suitable for writing or printing ink can create a final look.

Modern "paper vellum" is made of plant cellulose fibers and gets its name from its similar usage to actual vellum, as well as its high quality. It is used for a variety of purposes including tracing, technical drawings, plans and blueprints. Tracing paper is essentially the same thing, though the quality level differs, sometimes greatly.

Though Christopher de Hamel, an expert on medieval manuscripts, writes that "for most purposes the words parchment and vellum are interchangeable", a number of distinctions have been made in the past and present.

The word "vellum" is borrowed from Old French vélin 'calfskin', derived in turn from the Latin word vitulinum 'made from calf'. However, in Europe, from Roman times, the word was used for the best quality of prepared skin, regardless of the animal from which the hide was obtained. Calf, sheep, and goat were all commonly used, and other animals, including pig, deer, donkey, horse, or camel were used on occasion. The best quality, "uterine vellum", was said to be made from the skins of stillborn or unborn animals, although the term was also applied to fine quality skins made from young animals. However, there has long been much blurring of the boundaries between these terms. In 1519, William Horman could write in his Vulgaria: "That stouffe that we wrytte upon, and is made of beestis skynnes, is somtyme called parchement, somtyme velem, somtyme abortyve, somtyme membraan." Writing in 1936, Lee Ustick explained that:

To-day the distinction, among collectors of manuscripts, is that vellum is a highly refined form of skin, parchment a cruder form, usually thick, harsh, less highly polished than vellum, but with no distinction between skin of calf, or sheep, or of goat.

French sources, closer to the original etymology, tend to define velin as from calf only, while the British Standards Institution defines parchment as made from the split skin of several species, and vellum from the unsplit skin. In the usage of modern practitioners of the artistic crafts of writing, illuminating, lettering, and bookbinding, "vellum" is normally reserved for calfskin, while any other skin is called "parchment".