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Everything about Vellum Parchment totally explained

Vellum (from the Old French Vélin, for "calfskin") is a sort of processed animal hide that's thin, smooth, durable and was used in the pre-printing age to produce written works in the form of a scroll, codex or book.

Material

Strictly speaking in Jewish practice, vellum or klaf (Hebrew) should only be made from hide of a kosher animal, but in Christian Europe the term from the Roman times was used for the best quality of parchment regardless of the animal from which the hide was obtained. There is also a modern imitation "vellum" made from plasticized cotton. Like natural vellum, the synthetic is more dimensionally stable than a linen or paper sheet, which is frequently critical in the development of large scaled drawings and plans such as Blueprints. It was also extremely important in that reproduction technology for dissemination of the plans as like a high quality natural vellum, it could be produced in a thin enough sheet to be virtually transparent to strong light enabling a source drawing to be used directly in the reproduction of field-used drawings.
   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)
Drawing
type "name"
imensions
(width X height)
rawing
type "name"
imensions
(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 88.0 by 68.0 inches
224 cm by 173 cm
H-size 68.0 by 136 inches
173 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) equivalants were used widely outside the US.
Standardisation 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, but they're still called blueprints.
Drafting vellums eventually came to be standardized into a series of drawing sizes known as "A-size", "B-size", ..., "G-size" drawings which doubled in sheet size area with every step. Indeed, VLSI microcircuits themselves were layed out on such vellums layer by layer, "masked" to the dimensions of the given layer (a tracing step of sorts), and those masks photographed, all to scale in very large specialty light boxes. The negatives (known as photomicrographs, photo+micro+graph) thus obtained, were then step-reproduced in carefully aligned arrays and etched onto a glass plate Master of that layer.
   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 hay day of hand drafted blueprint technology technical workers found that working with a sketch was an aid to clear thinking.
   A small amount of true vellum is still made for writing Jewish scrolls of various sizes. The term can also refer to a manuscript or book written on such material.

Method of manufacture

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 any animal, including calfskin, sheepskin, or virtually any other skin obtained from a relatively small animal, for example, antelope, deer or goat and even a piglet although they're generally too small for the purpose, and equine foals although these are far too valuable as working animals. The terms vellum and parchment became confused early on; traditionally 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.
   The important distinction between vellum (or parchment) and leather is that the former isn't processed using tanning.

Manuscripts

All Sifrei Torah (Hebrew: ספר תורה ; plural: ספרי תורה, Sifrei Torah) are written on kosher klaf or vellum. Most medieval manuscripts, whether illuminated or not, were written on vellum. The very best quality, Uterine vellum, was made from the skins of still-born or even unborn animals. Some Gandharan Buddhist texts were written on 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.
   Another example of a document written on vellum is the Irish bog psalter, discovered in July 2006 in a bog in Ireland, which was written over 1,000 years ago.

Modern use

British Acts of Parliament are still printed on vellum for archival purposes., as are those of the Republic of Ireland
   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. Usually translucent, paper vellum is often used in applications where tracing is required, such as architectural plans. Some brands of writing-paper and other sorts of paper use the term "vellum" merely to suggest quality, when it's actually not vellum.

Preservation

Vellum is typically stored in a stable environment with constant temperature and 30% (+/-5%) relative humidity. If vellum is stored in an environment with less than 11% relative humidity, it becomes fragile, brittle, and susceptible to mechanical stresses; if it's stored in an environment with greater than 40% relative humidity, it becomes vulnerable to gelation and to mold or fungus growth.

Further Information

Get more info on 'Vellum Parchment'.


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