Vellum refers to parchment made from calf skin that can be found on old and rare books. Very old Bibles were printed on it, and so was the Declaration of Independence. Vellum is not like calf leather in that it is not tanned, but it does vary in softness and smoothness based on the quality of the skin and how it was prepared.
Typically, vellum is prepared by first being cleaned, bleached, and stretched, and then the skin is scraped with a crescent shaped knife called a “lunellum.” To end the process, the skin is wetted and dried repeatedly, and completed by abrading it with pumice and treating it with lime or chalk, which will ensure that it accepts writing or printing ink. The treatment of vellum has changed over time. In the early 19th century alkaline baths were used to remove the hair, and later in the century sulphur was added to the baths to quicken the process.
Vellum was, and still is, expensive to make and therefore seen as a sign of nobility. When it tore or had holes, it was sewn back together to prevent from getting worse. Some of these repairs are considered very beautiful, with twine webs reaching across the precious, rescued hide. Vellum is a rare, handmade good embedded in the old traditions of our ancestors.
It is essential that vellum be kept away from too high or too low humidity for preservation. The biggest risk with high humidity is mold, because vellum is particularly sensitive to moisture in the air. Store vellum at a humidity of 25% to 40% to prevent fluctuations which will cause the parchment to warp.
Light exposure is no friend to the materials of old and rare books. Extreme light exposure will form hydrogen peroxide in the vellum, causing it to break down or form gelatin. Being skin, vellum holds a lot of collagen and can become brittle or form biological growth with a large amount of light exposure.
Vellum is particularly difficult to preserve from being damaged or breaking down. But its value to culture, history, and craftsmanship of our ancestors makes it a worthy artifact for any collector. Here are just some rare books that we have available with vellum bindings:
The Works of Martin Luther, original full vellum.
Richard Wagner: His Life and Works from 1813-1834, original half vellum.
The Vicar of Wakefield, original vellum.