VELLUM. A medium, prepared from the skin of calves, for writing, painting, book binding and other purposes. A very prevalent misconception of the public is that parchment (see PARCHMENT) and vellum are one and the same. As a matter of fact the finer kinds of parchment are often termed vellum in com merce. Parchment, however, is produced from the skins of sheep, goats, etc., while true vellum is made solely from the skins of young calves. The difference between vellum and parchment consists not only in the delicate nature of the skin but in its polish, shining whiteness, its fineness generally and in its semi-transparent beauty not discoverable in parchment. While the skin of the call is required to produce vel lum, it is necessary that the animal be not over six weeks old, otherwise the skin is too stout for vellum and is destined for the tanner. The younger .the calf the finer the vellum; the most beautiful and sought for is that made from the still-born calf. The process of making vellum is more costly than that for parchment. Vel lum and parchment were the mediums upon which writing was done when papyrus fell into 'disuse to be displaced by these more substan tial materials. The art of preparing vellum was perfected by the monks during the 10th and 11th centuries. As a rule the vellum of manuscripts and deeds is white and very fine until the end of the 11th century, but some manuscripts dating from the 11th and 12th centuries present a somewhat dirty appearance and have writing rather yellowish, while other specimens are on beautiful vellum and the writ ing is intensely black. Of course the condition of whiteness of old documents depends some what on the care taken in preserving them.
The vellum of which fine manuscripts were made in the 14th century was called °per gamenum abortivum," referring undoubtedly .to the superfine vellum produced from the skins of still-born calves. The most luxuriously worked manuscripts were done on purple stained vellum, which was termed anecorella.A Silver lettering was done on this Numerous manuscript works of ancient date are extant done on purple, called °imperial stained.° A "grape-purple" vellum was prefer, ed for writing in silver (arguriography), crimson vellum for gold text (chrysography), "cooled" purple for vermilion ink (rubrica). It has been claimed that purple vellum was an invention of the 13th century, but the archbishop of York, Saint Wilfrid, in the 7th century, donated to his church a book of the Evangels in purple vellum written in gold letters and bound in a cover of leaves of gold and precious stones, which he himself had written and ornamented. In the case of many vellum manuscripts only part of the page is stained, as the color was very costly to work. In miniature painting the surface of vellum is rubbed over with pumice stone to do away with inequalities in the grain; this avoids any de fects in the absorption of the pigment in using this medium. In bookbinding vellum has been utilized with very artistic effects; plain white vellum binding has been termed Dutch style, while vellum with gilt decoration has been called Italian style.