In Europe the term from Roman times was used for the best quality of parchment regardless of the animal from which the hide was obtained, calf, sheep and goat all being commonly used. The very best quality, Uterine vellum, was made from the skins of stillborn or unborn animals. Strictly speaking in Jewish practice, vellum or klaf (Hebrew) should only be made from the hide of a kosher animal; deer was preferred historically.
Vellum was originally a translucent or opaque material produced from calfskin of an unborn calf that had been soaked, limed, and scudded (a depilatory process), and then dried at normal temperature under tension, usually on a wooden device called a stretching frame. However, except for Jewish use, animal vellum can include hide from calfskin, sheepskin, or virtually any other mammal, e.g., antelope, deer, goat or pigs. The terms vellum and parchment became confused early on; according to some sources the former was made from an unsplit calfskin, and consequently had a grain pattern on one side (unless removed by scraping), while the latter was produced from the flesh split of a sheep or goat or other kind of skin, and consequently had no grain pattern. Vellum always denoted the higher quality in any case.
Most of the finer sort of medieval manuscripts, whether illuminated or not, were written on vellum. Some Gandharan Buddhist texts were written on vellum, and all Sifrei Torah (Hebrew: ספר תורה ; plural: ספרי תורה, Sifrei Torah) are written on kosher klaf or vellum.
A quarter of the 180 copy edition of Johannes Gutenberg's first Bible printed in 1455 with movable type was also printed on vellum, presumably because his market expected this for a high-quality book. Paper soon took over for most book-printing, as it was cheaper and easier to process through a printing-press and bind.
In art, vellum was used widely for paintings, especially if they needed to be sent long distances, before canvas became widely used in about 1500, and continued to be used for drawings, and watercolours. Old master prints were sometimes printed on vellum, especially for presentation copies, until at least the seventeenth century.
Limp vellum or limp-parchment bindings were used frequently in the 16th and 17th centuries, and were sometimes gilt but were also often not embellished. In later centuries vellum has been more commonly used like leather, that is, as the covering for stiff board bindings. Vellum can be stained virtually any color but seldom is, as a great part of its beauty and appeal rests in its faint grain and hair markings, as well as its warmth and simplicity.
Lasting in excess of 1,000 years—Gregory the Great, Pastoral Care (Troyes, Bibliothèque Municipale, MS 504), for example dates from about 600 and is in excellent condition—animal vellum can be far more durable than paper. For this reason, many important documents have been written on animal vellum, such as diplomas. Indeed, referring to a diploma as a "sheepskin" alludes to the time when diplomas were written on vellum made from animal hides.
Today, because of low demand and complicated manufacturing process, animal vellum is expensive and hard to find. A modern imitation is made out 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" merely to suggest quality, when it is actually not vellum.
During the last century, antedating integrated CAD and modern laser printing which only came about after development of VLSI based microprocessors, synthetic vellums were at the heart of any large engineering or architectural project. "Blueprints" are a copy of such master drawings, and are used as the field and day to day references originally drafted on the vellum masters. Large paper drawings require an additional step (tracing paper amenable to letting light pass through it, and hence is more error prone)
(width X height)
| Drawing |
(width X height)
|A-size|| 08.5 by 11.0 inches |
022 cm by 028 cm
|B-size|| 11.0 by 17.0 inches |
028 cm by 043 cm
|C-size|| 17.0 by 22.0 inches |
043 cm by 056 cm
|D-size|| 22.0 by 34.0 inches |
056 cm by 086 cm
|E-size|| 34.0 by 44.0 inches |
086 cm by 112 cm
|F-size|| 44.0 by 68.0 inches |
112 cm by 173 cm
|G-size|| 68.0 by 88.0 inches |
173 cm by 224 cm
|H-size|| 88.0 by 136 inches |
224 cm by 345 cm
|As can be seen in the series, the width of the previous|
drawing size becomes the height of the next size in the sequence.
(Doubled dimension shown in italics in each pairing) The given series |
are the standardized sizes of the United States "MIL-SPEC" standards
(Military-Aerospace industrial complex) widely used in the United States,
though other (especially Architectural series) based on a different "base size"
(beginning drawing sizes) are also in common use commercially. The
MIL-SPEC series was also replicated by NATO countries, and so
metric (SI) equivalents were used widely outside the US.
Standardization was also driven by the need to have a compatible
blueprint reproduction ability where the copying technology is 1:1, so
non-MIL-SPEC variants differ only a small amount from commercial
alternative sized documents. Today's laser printed field use drawings
are usually "black on white" not blue on white or white on blue, but they are still called blueprints.
In short huge dimensional drawings representing the guts of an integrated circuit were scaled down optically and reproduced to produce each layer of the computer chips which eventually came to be part of the systems which replaced the vellums that made the CAD technology possible. Large scale hand drafted drawings in today's world are unusual and rare, but the old technology still exists and is the foundation upon which the modern computerized world is built. It is still common for engineers and architects to work out the details of a concept, so called "Sketches" on paper drawings before going to CAD. Even in the heyday of hand drafted blueprint technology technical workers found that working with a sketch was an aid to clear thinking.