Collection Care blog

5 posts from September 2013

30 September 2013

Here’s looking at you kid: Under the microscope with leather

We recently posted about parchment and how our conservators treat parchment collection items, but what is the difference between leather and parchment?

Parchment and leather are both made from animal pelts, but parchment does not undergo tanning as leather does. The process of tanning traditionally used tannin which is an acidic chemical compound making material less prone to decomposition - including molting and holding odours. Good leather is waterproof and more durable than parchment. These properties have led to leather being used for clothing, footwear, upholstery, armour, and as a writing material. Book bindings are sometimes covered with leather and display a grain pattern where follicles are observed. Follicles are mammalian skin organs that produce hair, and variations in their distribution and frequency can help researchers determine the species of animal used. Variations in texture, colour, and thickness of leather also offer clues.

Due to the variety of material in our collections, we have samples of different animal leathers in our conservation studios. The most commonly used varieties of covering material for bindings in the British Isles were calfskin, sheepskin and goatskin. Here we go under the microscope to take a look at the follicle distribution of goat, kid, calf and sheep leather.


The most frequently used tanned skin for binding was calfskin. It is often found plain but sometimes a pattern effect is achieved by staining with paint or acid. Cow hair is fairly evenly distributed and serves to insulate the animal’s body.

A zoomed-in image of a section of calf leather at 100x magnification. The calfskin presents as a pale cream colour with follicles facing in the direction from the lower left of the image to the top right in orientation.

Figure 1: Calf leather at 100x magnification. 


Microscopy of goat leather shows two rows of follicles of different sizes indicative of a two-coated fleece. The larger follicle is known as the primary follicle and produces the goat’s guard hair which is present all year round. The smaller follicles are called secondary follicles and produce an undercoat which grows more during the colder winter months. The undercoat is made up of soft, downy hair and is the hair used for fine materials such as cashmere when taken from Cashmere goats.

Zoomed-in image of the goat leather at 100x magnification. The skin tone is a pale colour and the texture has large and small follicles in a series of uneven rows.

Figure 2: Goat leather at 100x magnification. Two rows of follicles are observed; the smaller secondary follicles produce down while the larger primary follicles produce guard hair.


Young goats show a similar skin structure to the adult goat, but follicles are not as apparent in kid hides. Goat and kid leather was used for the best quality work being known for its well-grained, shiny and hard-wearing surface.

A zoomed-in image of kid leather at 100x magnification, with a similar colour to the goat leather. The follicles are not as pronounced and the skin looks more 'stretched' than the other examples.

Figure 3: Kid leather at 100x magnification.


Sheepskin has narrow follicles which produce crimped wool fibres. Crimped fibres distinguish wool from the straighter fibres found in hair or fur. It is this crimped profile which makes sheep’s wool a great insulator by trapping air and becoming bulky. Wool is also elastic and grows in clumps known as “staples” as observed below. Fine wool such as Merino has more crimps per inch than other wools.

An image of sheep leather at 100x magnification. The colour tone of the skin is cream, with the follicles presenting as brown. The follicles are narrower than the other skins, and seem more random, though mostly orientating towards the top of the image.

Figure 4: Sheep leather at 100x magnification. Clusters of follicles called staples are observed.

A comparison of animal leather in four images, clockwise: kid, goat, calf and sheep.

Figure 5: A comparison of parchment follicle patterns from kid, goat, sheep and calf at 200x magnification. 

Bookbinding leather

Tanned leather is difficult to shape into a flat and smooth surface free from wrinkles. It therefore quickly fell out of favour as a writing surface, but grew in popularity as a covering material for bookbinding. Leather is sometimes decorated with a worked design such as that seen on the St Cuthbert Gospel, which has a late 7th century binding. The leather cover was stained in crimson on the outer surface and moulded over a designed board while still damp. Tooling and the addition of other pigments enhanced the decoration.

An example of leather binding on a pocket gospel book. The frontispiece has beautiful Celtic knotwork framing a sigil of four intertwined finials. The entire cover is done in a rich brown-reddish leather, with some wearing to the board edge in the middle.

    Figure 6: Leather as a covering material on the front of the St Cuthbert Gospel.           

A zoomed-in image of leather binding standing out as reddish in tone. Black areas around the follicles appear flattened and are orientated from the right to the upper left of the image.

Figure 7: 50x magnification microscopy image of the leather on the back of the St Cuthbert Gospel; can you guess which animal this leather comes from?  

Red rot

Some animal breeders use the density of hair follicles in their promotional material as a means of promoting leather quality, but follicle density is related to surface area and is not necessarily indicative of an animal’s health. It is not surprising that the health of the animal is reflected in the quality of the leather produced. Agricultural improvements in the late 18th century led to larger animals with poorer quality skins. This combined with mechanised production methods and the use of condensed vegetable tannins contributed to leather which later suffered from red rot.

In the red rot process hydrogen peroxide is formed from the conversion of sulphur dioxide to sulphuric acid. Acid deterioration causes fine cracking and the formation of a red/brown powdery surface. The structural integrity is compromised and loss occurs. The powder can also transfer to reader’s hands and adjacent volumes.

A hardbound flexible tightback book, seen viewed fromthe lower edge of the spine. The book is sitting on a grey table. The red-rot can be seen along the tail and the leather area of the front board which has started to flake away.  Another shot of the same book, this time with the front board opened upwards. the red rot can be seen on the textblock, staining the bottom a pinkish colour.

An image of a hardbound book lying on it's side on a white piece of paper, on a grey table. The spine is facing the camera. The front board has detached completely, although is still sitting on the text block. The spine shows heavy wear on the head and tail, and the leather has worn away from the right-hand edges of four of the five bands. The entire book is a terracotta colour, indicative of major red rot, and the title and any spine decoration cannot be made out clearly. The white sheet underneath the book shows the red 'dust' shed from the book.

Figure 8: Examples of red rot on leather bindings. Red rot can cause boards to completely delaminate.
Leather binding, although tougher than parchment, still has many of the same preservation needs and should be kept free from fluctuations in relative humidity, light exposure, temperature fluctuations, dust build up and pest attack.

Christina Duffy (@DuffyChristina)

Imaging Scientist

23 September 2013

A Guide to British Library Book Stamps

Did you know that ownership stamps are applied to items accepted into our collections?

Ownership marking is the application of the official British Library ownership stamp. The ownership stamp is used for security purposes and in tracing the provenance of the collections. Examination of the book itself is quite often the best place to start when trying to establish the history of an antiquarian book, and library stamps (acquisition stamps and book stamps) might indicate how and when it was acquired. Ownership of an item was routinely shown by the British Museum, and subsequently the British Library, by using inked stamps. These stamps give a fairly precise date of receipt for the volume leading to entries in acquisitions registers or invoices. A series of stamps was compiled by René Payne in 2007 from which many of the examples in this post have been taken.

Our Library stamps are generally divided into four types according to when they were in use ranging from 1753 up to the present day. 

TYPE 1: 1753–1836

From 1753 to around 1836 stamps containing the words MVSEVM BRITANNICVM or MUSEUM BRITANNICUM were in use. The shape and arrangement of the stamp varied over the years and sometimes contained the initials of the previous owner.

A stamp on a light beige background. The stamp is black and is rectangular (horizontally,) with the top edge flowing into a downward facing triangle which has the initials 'CMC'. The lettering inside the main rectangle reads 'Museum Britannicum' in capitals, the 'U's in Roman style appearing as 'Vs'.
A library stamp specially cut to include the initials of the previous owner, Revd C.M. Cacherode.


A stamp in the top right hand corner of a document. The document is medium brown, with the stamp being black in colour, in a polygon shape. The stamped lettering within reads 'Museum Britannicum' with the U in roman style, appearing as a V. The lower part of the image is filled with a flowing script that overlaps each other and is difficult to see.
Stamps were often placed near areas of interest such as this inscription on IB 49437

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TYPE 2: 1837–1929

Type 2 stamps covered the period 1837-1929 and were oval in shape. They contained the royal arms flanked by a lion and unicorn beside the words BRITISH MUSEUM. Between 1837 and 1849 stamps were annotated with a pencil to indicate the exact date of entry in the acquisitions records. They occur in the shape of a diamond giving the date of acquisition and a reference line in the Acquisitions Register. In the example shown below from the Help for Researchers webpage, moving clockwise from the left the numbers represent  the month of acquisition (10 = October), the year of acquisition (44 = 1844), the day of acquisition (18 = 18th), and the entry line in the Acquisitions Register for that day (line 144).

An annotated stamp, much faded, but red in colour on a white or off-white background. the letters 10, 18 and 144 appear above it in handwriting likely as part of a text. The stamp's internal structure is faded and hard to see, but appeas to be a Lion and Unicorn surrounded a coat of arms topped with a crown. The writing above within the stamp says 'British Museum'.
Annotated library stamp in volume at shelfmark 1462.h.4 [Vitterhets Arbeten by G.F. Creutz and G.F. Gyllenborg (1812)]. 
A much faded stamp, appearing yellowish in colour but likely originally red, on a white paper background. The stamp is ovoid, with 'British Museum' on the (inner) top and bottom, and the date 'SE (for Sept) 1 1905' in the middle.On the page itself is printed 'Vol IV' on the top of the image and at the bottom under two lines of differing thickness, is the date '1903'.
Oval stamp issued on 1 September 1905


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A Type 2 Patent Office stamp, in blue on a pale background. The stamp bears the Lion and Unicorn surrounding the coat of arms and around the top inside the stamp is 'Patent Office' in capitals, and separated by two stars on either side of the sigil, of which underneath is 'Library'.
As seen in the journal The Lancet on 20 February 1915.


A Type 2 British Museum stamp. The ovoid stamp is blue on the pale background of the paper. The stamp bears a large crown in the centre, with four dots on the top and bottom, and two starts at the sides. Above within the stamp. is 'British Museum' in capitals, and the date underneath (also within the stamp) which is 25 October 1920.
British Museum stamp dating 25 October 1920 showing a variation of the crown in an oval

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Type 2 oval stamp. The Stamp is ovoid and is coloured blue, with 'British Museum' under the top edge. The heraldry of the Lion and Unicorn supporting the coat of arms with a crown atop. They in turn are supported by a flowing scroll with unreadable writing.   Type 2 oval stamp. The Stamp is ovoid and is coloured red, with 'British Museum' under the top edge. The heraldry of the Lion and Unicorn supporting the coat of arms with a crown atop. They in turn are supported by a flowing scroll with unreadable writing.

CC by Figure 4: Oval stamps containing the royal arms flanked by a lion and unicorn with the words BRITISH MUSEUM; used 1837-1929. An abbreviated date of acquisition may be added, either with another inked stamp or in pencil. Note the variation in design. After 1929, the stamp was changed to Figure 5 (left)

TYPE 3: 1929–1973

Type 3 stamps were used from 1929 to 1973. They consist of round stamps containing the royal arms but no lion or unicorn, and the words BRITISH MUSEUM. Earlier stamps included an abbreviated date of acquisition e.g. in Figure 5 (left) the date is 15 February 1944.

Type 3 round stamp. This image is a close up of the circular stamp, slightly unusual in that the stamp itself is solidly red, instead of only red lines. The central image is the coat of arms,bound in a circle with latin writing. At the centre edges on the left is '15' and on the right is '44'. underneath (still within the stamp) is 'Feb' in capitals, and above the coat of arms and the five-pointed crown is a banner emblazoned 'British Museum' again in capitals.
Round British Museum stamp with abbreviated date of 15 February 1944.


Type 3 round stamp. This image in close up, is of the red-coloured stamp. This stamp has no bounding lines and is open, though it is still circular. The image is of a large crown, with four dots at the top and bottom corners. Above the crown is 'British' and below it is 'Museum' all in capitals.
British Museum hand stamp used in small books and delicate or rare items


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Type 3 British Museum stamp, as stamped in the bottom left corner on this item. It has the same stamp as the previous image, that which is red and has no bounding lines, with the central large crown and 'British Museum' above and below it in capitals in a circular direction. The surface of the item appears slightly dirty with age at the corner, with possibly old creases or repaired tears. The framing of the image can be seen slightly in the top right corner.
British Museum stamp below an illumination on f.46v of Add MS 36928.


Type 3 British Museum stamp, the same stamp as the previous image, also in red. It lies underneath a portion of text in gothic script of four lines, in dark black font. The text underlines in possibly gold.
British Museum stamp below writing on Cotton Tiberius B8

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TYPE 4: 1973–present day

Type 4 stamps reflect the time when items were stamped with the words BRITISH LIBRARY rather than BRITISH MUSEUM - a key turning point in the History of the British Library. The British Library Act was passed by Parliament in 1972 which brought the Library into operation from 1 July 1973.

Type 4 India Office stamp. The stamp is blue and is rectangular in shape. There is no sigil, it is simply, in three lines, 'India Office' '03 Aug 1955' and 'Library' all capitalised. The 'Library and part of 'Office' are only partially visible.
India Office stamp dated 3 August 1955.


Type 4 Document Supply Centre stamp. This stamp is again rectangular, and blue in colour. Within the bounding lines in the top left corner is a logo in the shape of an open book, with 'B' and 'L' on the left and right of the open pages. Next to the logo is 'The British Library' in capitals. Underneath in centre is the date, '18 Jun 1980' capitalised and in a larger font. Underneath above the bottom bounding line is 'Official Publications Library' with 'Official' sitting above.
Document Supply Centre's official publication stamp dated 18 June 1980. It has been suggested that it differs from the round stamp because of where the item was received i.e. received in Yorkshire rather than London

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Type 4 stamp. This stamp is similar to the British Museum solid red circular stamps, but this one is solid Black. The coat of arms surmounted by the Crown is central, surrounded by the latin text. Outside the text on the left and right centre, is two clear circles, the left empty and the right with '81' inside. Above the crown is 'British Library' and belowon top of the bottom boundary is MAY all capitalised.
The words BRITISH MUSEUM were replaced with BRITISH LIBRARY, but retained a similar style to earlier stamps

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These round stamps have been applied to early printed books acquired since 1973.

Type 4 stamps. A series of three red stamps on one background. The first is simplistic, boasting a simple crown with 'B' and 'L' on either side at the centre, just over half the size of the crown in size. The middle crown appears much more detailed, with three tiers to the crowns base, and 'B.L' underneath. The third stamp is large than the other two. The Crown is the same simple depiction from the first image, but it has the text 'British library' above and below it, in capitals in a circular manner.
CC by Figure 9: Left: Hand stamp for a delicate or rare item. Centre: Crown hand stamp for Asia, Pacific and Africa Collections material. Right: Hand stamp for antiquarian material


Type 4 stamps. The first of these three images of stamps is green, small and faded. It consists of a crown with a slightly curved line through it. There is no text. The second stamp is red and large. It is a three tiered based crown, with 'British Library' above and below in a circular shape. Two dots are either side of the crown in the centre edge. The last stamp is green, roughly the same size as the red, with a crown with four maltese crosses on its base. It has 'I.O.R.' underneath.

CC by Figure 10: Left: hand stamp for a delicate or rare item. Centre: Hand stamp for manuscripts. Right: India Office hand stamp for small 'claim material' items. Treated as BL collection

The stamp in Figure 11 shows the initials OIOC (Oriental and India Office Collections) which now reside within the Library's Asia, Pacific and Africa Collections.

Type 4 stamps, a series of three. The first stamp is ovoid in shape, and is red, with the Lion and Unicorn supporting the coat of arms and crown in the centre. Above underneath the bounding line is 'British Library' capitalised. The second image is green, and is a slightly flatter ovid shape, like a rugby ball. The same sigil appears, but is smaller and less easy to discern. Above it underneath the bounding lines is 'India Office' and underneath is 'Records' all capitalised. The last image is also green, square and solidly coloured. Inside the square there are two '0's at the left hand corners, and on the right hand corners there is an 'I' and at bottom, a 'C'. In the centre stretching to the bounding lines is a circle, with the coat of arms and small text around the coat of arms, where 'British Library' can be made out. Underneath the coat of arms within the circle is another small circle, with 'Aug' within that.
CC by Figure 11: Left: Oval hand stamp for manuscripts with the words BRITISH LIBRARY. Centre: India Office hand stamp for non-small 'claim material' items. These items were treated as part of the British Library collection. Right: Library stamp from previous Oriental and India Office Collections. Use of this stamp ceased on 1 September 2005

Significance of the ink colour

Different colour ink was used for library stamps depending on the purpose. All inks have been tested to ensure they comply with conservation standards.

  • Blue ink represents legal copyright deposit material of British, Irish or colonial origin including material from the Old Royal Library 
  • Red ink typically indicates a purchased item, but a square red stamp may indicate that a book was donated as part of the Edwards Bequest 
  • Black ink was used on a wide range of early acquisitions, including books from the library of Sir Hans Sloane; on purchases made in 1781–1798 and 1804-1813; and on copyright deposit materials received 1813–1816. It was re-introduced for much of the 20th century to indicate materials acquired through international exchange. Black ink was discontinued on 1 September 2005
  • Green ink represents a donation made since 1944, or an exchange item
  • Yellow/orange ink represents donations made between 1768–1944 
  • Brown ink represents a donation made before 1768

While library stamps are a useful aid in determining the history of a collection item, it has been noted that many items were stamped much later than their acquisition date and mistakes are known to have occurred. Library stamps should provide just one piece of a greater body of evidence for determining both the circumstance and date of acquisition. Clues may also be found on bindings, bookplates or inscriptions. 

Ownership marking is carried out at St Pancras and Boston Spa in secure areas with restricted access. Our colleagues in the Operations Division are responsible for stamping any new material that comes into the library. A new system is being introduced very soon which we will cover in a future post. Thanks to Graeme Bentley, Goods Inward/Finishing Team Manager, for input on this topic.

Christina Duffy (@DuffyChristina)

Imaging Scientist

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.

09 September 2013

A-a-a-chooo! Collection Care’s Dust Busters

Dust is one of the most ubiquitous substances in the workplace, and nearly impossible to eradicate entirely. It can cause a range of problems to objects and collections, depending on its nature. The Preventive Conservation team in Collection Care work across all areas of the library putting measures in place to protect the collections from harm, to inhibit the progress of existing damage/deterioration, and to prevent new damage from occurring. The team are continually working to monitor and establish the causes of high and low dust levels to protect our collections.

A picture looking down from a high cream-coloured metal shelf, showing the dust that has built up to a substantial degree, covering the flat top of the shelf. To the left and right of the shelf can be seen hard-cover books of mostly larger size, on the adjoining shelves.

Figure 1: High shelf surfaces can experience severe dust build-up if not regularly cleaned.

What is dust?

Dust is a fine dry powder made up of tiny particles of earth or waste matter. It comes from a variety of sources including textile fibres, flakes of shed human skin and hair, pollution particulates, dead insect body parts, insect excrement, building materials (such as fragments of plaster, concrete and paint), soil carried on shoes, and pollen. If a collection item is sufficiently deteriorated then it can generate its own dust as it crumbles away. Lighter particles are capable of being airborne while heavier particles tend to remain in low-lying areas where they are first deposited. Airborne dust is more likely to be a problem in collections as it has a greater likelihood of being deposited on objects and shelves above floor level. It may also be readily spread by air conditioning systems.

A set of fourteen odd hardbound books of varying colours on a shelf, backed by a similar amount of books facing away on the other side. The books are covered with a large amount of dust on the text blocks,which has built up in piles and makes the paper text blocks appear grey in colour where the dust is thick.

Figure 2: Dust can gather on top of books and between bindings if neglected. Problems relating to dust go beyond aesthetics. 

Dust build up is affected by cleaning and housekeeping practises, room layouts and shelving location, human traffic patterns, air circulation, types of shelving and the type and condition of the books. Areas with a lot of human activity such as busy working areas or queues for reading rooms or photocopiers have been found to contain the most dust.

Problems caused by dust

The Preventive Conservation team closely monitors the type of dust as this may affect damage. Dust particles can act as an abrasive causing surface damage when objects are moved or subjected to mechanical cleaning. Building work may produce corrosive dust that needs to be cleaned quickly. Some types of dust particles may be alkaline or acidic promoting hydrolytic damage, especially if the surface is already damaged by abrasion. Dust which contains small amounts of plant pollen can worsen hay fever for anyone working or visiting at the library. Mould spores and pests which can attack collection items feed on dust particles. The house dust mite (Dermatophagoides pteronyssinus) who feeds on organic detritus material is ubiquitous in places that humans occupy.

A vaguely terrifying image of a House dust mite in a highly zoomed image in greyscale tone. The dustmite is actively walking, with it's head facing towards the right of the image. It's head is facing down, and is surrounded by four legs either side which taper into sharpish points. There are two back legs visible on the left hand side which join into it's underside at the rear. The mite appears quite rotund in appearance, with it's abdomen having the texture akin to a fingerprint. It looks nasty.

Figure 3: The house dust mite, Dermatophagoides pteronyssinus, feeds on particles already partially decomposed by fungi. 

Dust mites are arachnids, not insects, and they cannot control their body temperature. This means that the length of their life cycle varies with the temperature of their habitat. A female adult with a life cycle of about 4-6 weeks can produce 40-80 eggs. They produce about 2,000 fecal particles and even more partially digested enzyme-covered dust particles! Dust can also act as a respiratory irritant. Many people suffering with asthma have dust mite allergies which make dust control a health and safety issue.

Dust monitoring

Dust monitoring is part of the work carried out by the Preventative Conservation team. Dust can be monitored by visual inspection, long-term study, dust analysis (microscopy, spectroscopy), and instrumental methods such as laser light scattering. For most situations, the more sophisticated analytical methods are unnecessary – a simple visual inspection is generally adequate.

Cleaning helps alleviate the potential for dust to cause damage to collections. Methods of cleaning must be chosen to be appropriate both to the object and the type of dust.

Three books, hardbound in brown leather, can be seen with a good deal of dust on their textblocks. There are fingerprints on the middle book, showing the depth of the dust. A wooden bookcase, in a warm wood, possibly pine, with a large amount of dust on it shelf. Towards the lip of the shelf the dust has been disturbed by hands and fingers, showing the amount of dust which is on the shelf.
Figure 4: If you can write your name on surfaces, it’s probably time for a clean!

The effects of dust can be reduced by moving items in high risk areas, changing shelving types, or boxing items. Static shelving (especially close to working areas) is much dustier than mobile shelving which may encourage some fall-out of dust from canopies preventing build-up. It is difficult to protect collections entirely from dust, especially as high value items are in busy areas due to high reader demand. Boxing of material is only practical for single items or small collection items with special needs.

Balancing benefits and risks

Any changes to minimise dust should not increase risks to the collections from other factors. Care must be taken that the additional handling of the books whilst cleaning, and the danger of dust particles acting as an abrasive during mechanical removal, does not cause more damage than it prevents. For example rearranging books or shelving should not result in collections becoming more vulnerable to theft, or making retrieval more difficult or inconvenient. Similarly, altering air flow patterns should not raise relative humidity and/or temperatures which may encourage mould and pests.

Contact the Preservation Advisory Centre for advice on dust monitoring and dust surveys. Make sure you read our free to download booklet on cleaning books and documents for the best way to approach a cleaning plan.

More reading: Dust mites by Matthew J Colloff, CSIRO Entomology publishing. Informazione Medica Pazienti: Advice for patients allergic to dust mites.

Christina Duffy (@DuffyChristina)

03 September 2013

The Twelve Principles of Digital Preservation (and a cartridge in a repository…)

Did you know that our digital library store already holds over 11,500,000 items? That’s over 280 terabytes of collection content, and more is added every day!

Our blog has so far focussed on how Collection Care colleagues work to preserve the Library’s physical collections, but the Library also works to preserve our digital content making collections accessible for future users. Digital content ranges from digital audio/video recordings, to personal digital archives, eJournals and archived websites. The preservation of digital content is spearheaded by the Digital Preservation Unit in Collection Care. Head of Digital Preservation Maureen Pennock introduces the role of the team and outlines the Twelve Principles of Digital Preservation:

The Digital Preservation Unit in Collection Care provides guidance, advice and support for operational colleagues across the Library to ensure our digital collections are preserved efficiently and effectively. We are a small team with a big mission – our digital collections are growing day by day, and preservation actions must be implemented right throughout the lifecycle, from creation onwards, if we are to preserve authentic and understandable content.

An image of a section of Digital storage server. The visible parts of the server are silvery-grey, mounted into a dark grey or black bases, on a tower structure. There is a glass or perspex door on the right of the image that may enclose the visible section.
The diversity of digital material and frequent changes in computer technology present ongoing challenges for long term preservation and access

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Following on from the launch of the Library’s Digital Preservation Strategy earlier in the year, which defined our four strategic priorities for 2013 – 2016, we are pleased to release our Twelve Principles of Digital Preservation. These principles define at a very high level how we as a Library will approach the preservation of our digital collections:

1. We integrate curatorial assessments of our digital collection content into preservation decisions, so that technical activities support curatorial requirements for the collections

2. We preserve metadata about our digital collections, so that we may understand and preserve the collections over time

3. We preserve the provenance of our digital collection content, so that we understand and can demonstrate its authenticity over time

4. We record any modifications to digital collection content (e.g. preservation action, normalisation) during the lifecycle, so that we can understand and demonstrate its integrity over time

5. We consistently apply and document our application of metadata standards, so that future generations can understand our collections

6. We maintain file-level integrity of our digital collections, so that we can protect against loss and damage

7. We preserve original files in our long term repository, alongside any other required representations of the content, so that we maintain the original artefacts acquired or deposited into our care as a ground truth representation of the content for future, currently unknown, preservation and access scenarios

8. We maintain Preservation Master copies of collection content in our long term repository, so that the format-based risks of preservation over time are minimised

9. We maintain and implement preservation plans for our digital collections, so that preservation actions are reliable and based on a holistic understanding of the collections and their context

10. We implement comprehensive end-to-end workflows, so that we may consistently manage and preserve our digital collections across the entire lifecycle

11. We regularly monitor our digital collection content for emergent preservation risks, so that we may mitigate against them

12. We integrate quality assurance checks into the lifecycle where appropriate, so that the authenticity and integrity of the content is maintained

These Principles are the first output of a workstream dedicated to defining the Library’s digital preservation standards. More work is already underway to define the policies that will be associated with each principle and, in turn, the resulting requirements for meeting that policy. This workstream is part of a larger programme of work being undertaken in digital preservation to ensure our strategic priorities are met. Other activities include:

• a collection profiling exercise to provide top level descriptions and preservation direction for different types of digital collections (eg e-theses, web archives, ebooks, AV material etc)

• a risk and preservation condition assessment exercise for content temporarily stored outside of our long term digital repository

• a file format assessment exercise to define preferred preservation formats for different types of content

• a tool assessment exercise to evaluate the performance of different tools on library content so that evidence-based recommendations can be made on which tools to use in which context

• a training programme to ensure colleagues across the library are aware of digital preservation responsibilities, requirements, and recommendations relevant whilst content is in their care

A technician holding a piece of paper or card, is standing next to a computer monitor on a table, which itself in on the right hand side of the Zeutschel Scanner. The Technician is wearing a maroon shirt and dark trousers. The computer monitor is displaying opened pages that have been scanned. The scanner, which has a bright red girder structure rising up and joined to the camera, which is mounted in a grey unit overhanging the glass table. Underneath the glass are items to be scanned.
Digitisation projects are increasing in frequency each year highlighting the need for preservation measures.

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The Principles are designed to help ensure that preservation is considered in appropriate projects and initiatives regardless of whether or not the digital preservation unit is actively involved. Compliance checks will be initiated as part of a Collection care monitoring service. In coming months we will be working closely with other colleagues across the Library in defining appropriate and realistic policies, followed by requirements.

We’ll post our progress to the blog in due course. Watch this space..!

Maureen Pennock