Collection Care blog

10 September 2013

Is not parchment made of sheepskins? Ay, my lord, and of calfskins too...

Hamlet (Act V, Scene I), William Shakespeare

Parchment and vellum

Parchment is an animal pelt, most often sheep, calf, or goatskin, which has been unhaired by liming or enzymatic action and then stretched on a frame while wet. This stretching and drying under tension causes the collagen fibres in the dermal layer to be realigned resulting in a thin, opaque membrane. Most commonly used as a writing substrate, parchment is also used as a covering for bookbindings and to make drumheads, among other things.

This woodblock print depicts a parchment maker in the centre of the composition. To the right is the skin stretched on a frame, and the maker is using a tool to thin down the parchment. There are more skins on frames to the left, a bucket with water on the left in the foreground, and in the background is a cityscape.
Parchment maker at work. Woodblock print by Jost Amman, from Das Ständebuch (1568).


Named for the ancient city of Pergamum, where the manufacturing technique is believed to have been developed around the 2nd century BCE, parchment was the principal substrate for writing in Europe throughout the Middle Ages until it was gradually superseded by paper, which could be manufactured more cheaply and in greater quantity. Parchment has persisted, however, remaining popular for official documents and presentation copies. Indeed, you might be surprised to learn that UK Acts of Parliament are still printed on parchment today and it was even used for the marriage certificate of the Duke and Duchess of Cambridge!

What of vellum?

Though the terms parchment and vellum are often used interchangeably, strictly speaking vellum is parchment made from calfskin (from the Old French vélin, meaning calf). Vellum can also be used to describe parchment of superior fineness or quality.

A page from the Lindisfarne Gospels, which features text in the centre surrounded by a rectangular border. The page is beautifully illuminated with many colours.   The Magna Carta is depicted here. The parchment is tan in colour with brown text written across it, filling nearly the entire size of the parchment with just a small margin at the bottom.

CC_bySome of the most important Treasures of the British Library, including the Lindisfarne Gospels (left) and the Magna Carta (right) are written on parchment and vellum.

The Lyte Pedigree

The Lyte Pedigree, (BL Additional MS 48343) c.1605, is a manuscript copy of the royal genealogy in iron gall ink on parchment. It is the work of the genealogist Thomas Lyte, who also wrote Britianes Monarchie, a manuscript tracing the ancestry of King James I (BL Add. MS 59741). The Pedigree is one of two copies of the royal genealogy prepared by Lyte for James I. The other, an illuminated copy on paper presented to the King in 1610, is no longer extant.

James I sits on the throne centrally in this image. There are columns to either side of him. On the left hand side is the bust of a figure with a document at chest height, and falling down from that document is a series of circles that appear as if strung from string held taut. At the bottom of each 'strand' is an oval with a portrait contained within. To the right of the document is another version of a family tree, with portraits in ovals surrounded by foliage.
Add. MS 48343. Detail depicting James I enthroned beneath a canopy, with orb and sceptre, and wearing crown and garter, followed by a long dedication.


Originally a rectangle comprising nine parchment skins, the genealogy is now a cruciform shape comprising five skins, with the four corner skins having been lost. The genealogy is over two metres wide and almost two meters high.

Conservation treatment

The Lyte Pedigree first came to the Centre for Conservation in spring 2012 in order to be prepared for loan to the British Museum for the exhibition, Shakespeare: Staging the World, which opened in July 2012.

For storage the two side panels had been folded in and the document had been rolled. This, combined with heavy parchment repairs over the joints on the verso, had resulted in extensive creasing and cockling and meant that the genealogy would not lie flat, as it was intended to be displayed in the exhibition.

The document rests on a table and has started to be unfolded. The document curls readily, only staying down where small bag weights have been placed.   The document rests open now on a table, with bag weights placed around it to hold it open.

CC_by The genealogy when it first arrived in the Centre for Conservation. Notice the extensive cockling, sharp creases and how it will not lie flat without being weighted.

The genealogy was opened in the studio and the heavy joining strips on the verso were removed, as were some old silk gauze repairs on the recto. A number of temporary repairs were carried out using Japanese paper and wheatstarch paste and the genealogy was left open to relax under light weight for several weeks. It was recommended that a more appropriate storage solution be found once the genealogy returned from the exhibition.

A closeup of the back of the document is shown here, with a hand holding it in the foreground. There is a white strip of parchment at the join, which contrasts against the more tanned colour of the document itself.   The document rests as flat as possible on a table. Glass weights hold it open and various conservation materials including paper surround the item.

CC_by One of the heavy parchment strips over the joints on the verso, already beginning to detach (left) and the genealogy following their removal (right).

Since the genealogy is comprised of five individual animal skins, each has unique tensions and stresses. The use of newer parchment for repairs had exacerbated the tension resulting in extensive cockling and creasing. This, combined with the rolled storage, meant that the genealogy was difficult to handle and vulnerable to damage during consultation.

Following consultation with the curators, it was agreed that upon return from the exhibition, the five skins would be separated and individually mounted. Not only would this be more conducive to the long term preservation of the genealogy, it would also allow for easier handling and facilitate consultation. It was proposed that the skins be flush-mounted, which would enable the genealogy to be exhibited as a whole by placing each skin adjacent to the next in its original position.

Parchment is a very hygroscopic material as it can easily absorb moisture from the air and is very vulnerable to rapid changes in humidity. Aged parchment is particularly vulnerable due to the breakdown of the collagen fibres over time. Too much moisture can result in gelatinisation and complete loss of structural integrity. As a result any conservation treatment on parchment must minimise the use of water. Humidification is carried out rarely and always in a minimal, slow, and controlled manner.

Once the five skins had been separated from each other they were first allowed to acclimatise to the atmosphere in the studio under a light weight for a number of weeks.

After careful deliberation, it was decided that in this case, due to the severity of the cockling and creasing, gentle humidification would be necessary. A combination of techniques was used. First, two of the most cockled skins were humidified in a cedarwood chamber, raising the humidity to 70% RH for several hours. The cedarwood chamber was lined with damp capillary matting, followed by a layer of Gore-Tex, which allows water vapour (but not liquid water) to pass through it. The document was then placed in the chamber on a sheet of Bondina, a humidity meter is placed inside, and a Perspex sheet placed on top, sealing the chamber. Second, local humidification using a cold ultrasonic mist was applied to sharp creases in the two side panels where they had been folded in for rolling. After humidification the parchment was dried under tension using magnets.

The cedarwood chamber, which comprises of found sheets of wood put together in a rectangular shape.   An illustration depicting the layers used in the chamber. From the bottom: capillary matting, Goretex, Bondina, the parchment object.

CC_by Humidification of parchment using a cedarwood chamber.

A closeup of part of the object showing creases.   The same area as in the previous photograph which now looks more flattened.

CC_by Creased areas before (left) and after treatment (right) with ultrasonic mist humidification and drying using magnets.

As the parchment gradually relaxed and the cockling reduced, some of the remaining old parchment repairs began to lift and cause greater tension. It was decided that they should be removed and new repairs were made using remoistenable Japanese paper. Losses were built up using layers of paper, toned to blend with the parchment. Remoistenable tissue has been pre-coated with a thin layer of adhesive (in this case Isinglass) which can then be reactivated using a minimal amount of moisture. It is used for repairs when it is necessary to keep moisture to a minimum, such as in parchment conservation and when repairing documents with iron gall ink or fugitive media.

A closeup of an old parchment repair which is oval shaped and a stark white in comparison to the tan colour of the document.   A oval-shaped piece of Japanese tissue rests on the front of the object. It is more tan in colour, suggesting it will be a more sympathetic repair visually.

CC_by Lifting old parchment repairs (left, showing verso) were replaced with new repairs using remoistenable Japanese paper (right, showing recto).

Following conservation, the individual parchment skins were mounted on corrugated board using tabs of Japanese paper. Narrow tabs (10mm) were spaced at 30mm intervals to ensure even tension across the skin. The weight of the paper was carefully chosen to be weaker than the parchment so that in the event the parchment were to move, the paper tabs (and not the parchment) would tear.

The document is shown upside down with the tabs running along all sides.   In the foreground rests the document, and in the background a conservator wraps one part of the document onto archival board.

CC_by Tabs of Japanese paper were adhered to the verso, overlapping the edge by 2-3mm, using dry wheatstarch paste (left). These were wrapped around archival corrugated board (cut to the size of the parchment) and pasted on the verso of the board (right).

Finally, each mounted skin was placed in a Plastazote recess to compensate for the natural undulations in the parchment and prevent abrasion of the surface, then housed in a phase box. Plastazote is a chemically inert polyethylene foam commonly used for conservation enclosures.

  The top piece of the document after treatment.  
The middle left piece of the document after treatment. The centre piece of the document after treatment. The middle right piece of the document after treatment.
  The bottom piece of the document after treatment.  

CC_by The Lyte Pedigree after conservation treatment and rehousing, shown in its original cruciform arrangement.

Further reading:

Clarkson, C. (1992) Rediscovering Parchment: The Nature of the Beast. In: The Paper Conservator, Vol. 16 (1), pp. 5-26.

Reed, R. (1972) Ancient Skins, Parchments and Leathers. London: Seminar Press.

Mariluz Beltran de Guevara
Conservation Team Leader / Specialist in the conservation of vellum and parchment.


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