Vellum - Manufacture

Manufacture

Vellum is a translucent material produced from the skin, often split, of a young animal. The skin is washed with water and lime (Calcium hydroxide), but not together. It is then soaked in lime for several days to soften and remove the hair. Once clear, the two sides of the skin are distinct: the side facing inside the animal and the hair side. The “inside body side” of the skin is the usually lighter and more refined of the two. The hair follicles may be visible on the outer side, together with any scarring, made while 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 the skin is dried by attaching it to a frame (a “herse”). The skin is attached at points around the circumference with cords; to prevent tearing, the maker wraps the area of the skin to which the cord is to be attached around a pebble (a “pippin”). The maker then uses a crescent shaped knife, (a “lunarium” or “lunellum”), to clean off any remaining hairs. Once the skin is completely dry, it is thoroughly cleaned and processed into sheets. The number of sheets extracted from the piece of skin depends on the size of the skin and the given dimensions requested by the order. For example, the average calfskin can provide three and half medium sheets of writing material. This can be doubled when it is folded into two conjoint leaves, also known as a bifolium. Historians have found evidence of manuscripts where the scribe wrote down the medieval instructions now followed by modern membrane makers. The membrane is then rubbed with a round flat object (“pouncing”) to ensure that the ink would adhere well.

The important distinction between vellum (or parchment) and leather is that the former is not processed using tanning techniques. The distinction between vellum and parchment has been made in several different ways, and no one definition can be considered correct, but vellum has always denoted the better quality.

In Europe, from Roman times, the term vellum was used for the best quality of prepared skin, regardless of the animal from which the hide was obtained, calf, sheep, and goat all being commonly used (other animals, including pig, deer, donkey, horse, or camel have been used). Although the term derives from the French for "calf", except for Muslim or Jewish use, animal vellum can include hide from virtually any other mammal. 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. Many libraries and museums increasingly use only the safe if confusing term "membrane"; depending on factors such as the method of preparation it may be very hard to determine the animal involved without using a laboratory, and the term avoids the need to distinguish between vellum and parchment.

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".