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). The making of vellum involves the cleaning, bleaching, stretching on a frame (herse), and scraping of the skin with a crescent-shaped knife (lunellum). To create tension, the process alternates between scraping, wetting, and drying. The surface is then cleaned with pumice, and treated with lime or chalk to make it suitable for writing, and to give it its final look. ==Terminology==

Modern scholars and experts often prefer to use the broader term membrane, which avoids the need to draw a distinction between vellum and parchment, as it is very hard to determine the type of animal involved, let alone its age, without detailed scientific analysis. from the 7th century written on vellum 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. Writing in 1936, Lee Ustick explained that: 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. ==Manufacture==

(map) by Jacopo Russo (Giacomo Russo) of Messina (1533) Vellum allows some light to pass through it. It is made from the skin of a young animal. The skin is washed with water and lime (calcium hydroxide), and then soaked in lime for several days to soften and remove the hair. Once clear, the two sides of the skin are distinct: the body side and the hairy side. The "inside body side" of the skin is usually the lighter and more refined of the two. The hair follicles may be visible on the outer side, together with any scars from when the animal was alive. The membrane can also show the pattern of the animal's vein network called the veining of the sheet. Any remaining hair is removed (scudding) and to dry it out the skin is attached to a frame (a herse) The makers rubbed the sheets with a round, flat object ("pouncing") to ensure that the ink would adhere to the surface. Even so, some types of ink would gradually flake off as the membrane was folded, rolled, or rubbed. ==Manuscripts==

Preparing manuscripts Once the vellum is prepared, traditionally a quire is formed of a group of several sheets. Raymond Clemens and Timothy Graham point out, in their Introduction to Manuscript Studies, that "the quire was the scribe's basic writing unit throughout the Middle Ages". as are those of the Republic of Ireland. In February 2016, the UK House of Lords announced that legislation would be printed on archival paper instead of the traditional vellum from April 2016. However, Cabinet Office Minister Matthew Hancock intervened by agreeing to fund the continued use of vellum from the Cabinet Office budget. On 2017, the House of Commons Commission agreed that it would provide front and back vellum covers for record copies of Acts. Today, because of low demand and a complicated manufacturing process, animal vellum is expensive and hard to find. The only UK company still producing traditional parchment and vellum is William Cowley (established 1870), which is based in Newport Pagnell, Buckinghamshire. A modern imitation is made of cotton. Known as paper vellum, this material is considerably cheaper than animal vellum and can be found in most art and drafting supply stores. Some brands of writing paper and other sorts of paper use the term "vellum" to suggest quality. Vellum is still used for Jewish scrolls, particularly the Torah, for luxury bookbinding, memorial books, and various documents in calligraphy. It is also used on instruments such as the banjo and the bodhran, although synthetic skins are available for these instruments and have become more commonly used. The Catholic Church still issues its decrees and diplomas for its officials on vellum. Paper vellum Modern paper vellum is made from plant cellulose fibers and gets its name from its use similar to that of 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. ==Preservation==

Vellum is ideally stored in a stable environment with a constant temperature and 30% (±5%) relative humidity. If vellum is stored in an environment with less than 11% relative humidity, it becomes fragile and vulnerable to mechanical stresses. However, if it is stored in an environment with greater than 40% relative humidity, it becomes vulnerable to gelation and to mould or fungus growth. The optimal relative humidity for proper storage of vellum does not overlap that of paper, which poses a challenge for libraries. The optimal temperature for the keeping of vellum is approximately . ==See also==