Warriors, Weapons and Horses: conserving folios from a Mamluk manuscript

The Mamluks ruled Syria and Egypt from 1250 until they were defeated by the Ottoman’s in 1517. Very few illustrated manuscripts from this era have survived, but one of them is held at the Chester Beatty. This bound manuscript (CBL Ar 5655), dating from the mid-14th century, is a Compendium of Military Arts featuring warfare, weaponry and horsemanship.  Twelve separate folios from the manuscript have recently been conserved in preparation for our upcoming temporary exhibition, Gift of a Lifetime (opening on 19th October 2018).

Fig 1

CBL Ar 5655.134 before treatment.

The thickly applied white pigment (probably lead white) on the faces and turbans of the warriors had suffered serious cracking and in some cases small losses. In other more localised areas there was cracking and slight flaking/powdering of some pigments, particularly in association with creases in the paper. It is also likely that the smooth surface of the highly burnished paper support had contributed to the loss of media.

Fig 2

Left: Cracking of media associated with creases in the paper (CBL Ar 5655.134); Right: Flaking white pigment (CBL Ar 5655.134).

All of the pigments were checked under magnification and consolidated as needed using Bermocoll, a synthetic cellulose-based adhesive. Isopropanol was applied to the edge of the flaking areas using a very fine brush, directly followed by the adhesive applied with a second brush. The alcohol acts as a wetting agent, reducing the surface tension of the adhesive so it is drawn underneath the flaking pigment layer by capillary action. On drying, the adhesive secures the fragile pigment layer to the paper below.

On a number of folios the paper along the spine edge was fragile and torn with paper fibres at risk of being lost. A small number of tears along the creases in the paper were also apparent. The folios had been repaired in the past and although these historic repairs were indiscreet it was decided that they should be left intact because they had not caused any damage to the folios and can now be considered to be part of the object’s history.

Fig 3

CBL Ar 5655.159 in transmitted light, showing the historic repairs.

Repairs were carried out to stabilise the damaged areas of paper and ensure that no further damage would occur through handling. As the thin Islamic paper was particularly susceptible to distortion with the addition of moisture, the repair methods were chosen carefully to ensure that only a very small amount of moisture was introduced. The tears were repaired using remoistenable tissue, a very thin Japanese tengujo paper pre-prepared with 1% methyl cellulose adhesive. Along the spine edge the loose fibres were secured with thick wheat starch paste. In some areas bridge repairs were added to support small parts of the paper that were at risk of detaching.

Fig 4

Left: Repairing a tear on CBL Ar 5655.161 using remoistenable tissue; Right: Applying small bridge repairs to the spine edge of CBL Ar 5655.162.

For the bridge repairs, Japanese paper fibres were teased out from the torn edge of a long-fibred kozo paper and rolled together between finger and thumb to create tiny bridges. The repair fibres were then pasted with wheat starch paste and positioned carefully across the damaged areas.

Fig 5

Detail of the spine edge of CBL Ar 5655.134, before treatment in transmitted light (left) and after treatment (right).

Whilst working on these charming miniatures I had the chance to observe some of the techniques used by the artist(s). Scoring lines (visible in raking light) had been used to plan out the symmetrical designs and under-drawing was visible where the pigments had been lost from the faces and turbans. Interestingly, the pigment on the back of the black horses had a shiny finish and there was slight cupping of the painted surface. This suggests that a surface coating was applied locally over the black pigment before burnishing to create this lustrous finish. The undersides of the black horses were left without this additional surface treatment leaving the pigment more matte, possibly to give the effect of shading.

Fig 6

Left: Ar 5655.167 in raking light, showing the scoring lines used to map out the design; Right: Ar 5655.156, showing both shiny and matte media on the black horse.

Fig 7

Mounting the Ar 5655 folios.

After treatment, the Mamluk folios were secured in window mounts using T-hinges made from Japanese sekishu paper adhered with wheat starch paste. The folios will be on display alongside other treasures from the Chester Beatty collection, in the exhibition ‘Gift of a Lifetime’ (19th October 2018—28th April 2019). We do hope you’ll come and see it!

Alice Derham, Heritage Council Intern in Conservation

Celebrating the 50th anniversary of Sir Alfred Chester Beatty’s magnificent bequest, Gift of a Lifetime (19 October 2018 – 28 April 2019) presents a choice selection of masterpieces from this unique collection. You can find out more about some of the treasures in the exhibition here

 

 

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Miniature Masterpiece: The Coëtivy Hours

The conservation team have been busy preparing 144 exquisite illuminated miniatures from a manuscript dating to c. 1443, for our next temporary exhibition ‘Miniature Masterpiece: The Coëtivy Hours’.

The Coëtivy Hours (CBL W 082) was made for the renowned book collector, Prigent de Coëtivy (1400-1450), who was Admiral of France at the time. The book was specifically commissioned to commemorate his marriage to Marie de Rais in Paris in 1444. Nearly 500 years later, the book was given to Chester Beatty by his wife, Edith, on the occasion of their wedding anniversary in 1919.

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Fig. 1. The Coëtivy Book of Hours (left) and miniatures housed between glass (right), before conservation.

The tiny manuscript (14.2 x 11.3 x 4.2 cm) is bound in an intricately tooled early nineteenth-century binding. The 364 folios are skilfully painted, with highly decorative borders throughout the manuscript.  However, 144 of the 148 three-quarter page miniatures were removed from the book by Beatty soon after it came into his collection, as he wanted people to be able to ‘look at them as closely as they want and study them properly’. They were therefore stored between glass to aid their preservation and display.

Although the book itself did not require conservation treatment, it was decided that the miniatures should be removed from the glass in order to facilitate their digitisation and enable safe handling by researchers in the future. When the glass sandwiches were opened, it became clear that each folio had been attached to the glass at the top and bottom of the spine edge with pressure-sensitive tape. Thankfully, the carrier of the tape was easily removed with a metal spatula. The rubber-based adhesive left dark residual staining, but it was decided that this would not be removed as in some cases the staining was in contact with the original media and solvent treatment would be too risky.

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Fig. 2. Removing folio 291 from glass.

The parchment folios of the manuscript are very thin and have very few visible flaws, indicating that they were made from carefully selected and evenly prepared skins. Scientific analysis by the BioArCh team at the University of York revealed that both calf and goatskin were used in the Coëtivy Hours. Overall, the media was in excellent condition, and did not require consolidation. In some areas there were losses to the blue pigment and gold leaf, but the areas around these losses appeared to be stable and, when examined closely, there was no active flaking of the media.

After the folios were condition checked, the new Digital Department at the Chester Beatty Library took high quality images of every folio using a Phase One XF camera with an IQ380 attachment, capable of producing images with a resolution of 80 megapixels (look out for the new digitisation blog that is coming soon!). The opening of the nineteenth-century binding was somewhat restricted, allowing it to open to little more than 90 degrees, so the conservation team provided advice on handling and helped to ensure the manuscript was supported on a cradle throughout digitisation, whilst the pages were held in place with polyethylene straps from Benchmark.

Fig. 3
Fig. 3. Digitisation of the Coëtivy Book of Hours.

When devising a mounting system for the individual parchment folios, it was important to choose a system that would be strong enough to hold the folios safely in place during display and handling, but allow the parchment to move with natural fluctuations in relative humidity and temperature. The mounting system also needed to take into account the unique contours of each folio. For this reason, a bespoke system of Japanese paper tabs was used to mount the folios within window mounts.

The majority of the folios were mounted in pairs, in a standard size mount made from acid-free, buffered Conservation Board (1650 micron), with a standardised aperture. Each folio was over mounted on the spine edge only, with the other three edges floated just a couple of millimetres inside the aperture. This partial float mounting system ensured that each folio was held in place securely, but also offered room for the parchment to expand and contract. Aesthetically, the mounting also reflects the character of the object and reminds the viewer that the miniatures are not only artworks in their own right, but are folios from a bound manuscript volume.

Two sizes of tabs were used on each folio – two 25mm tabs of Japanese sekishu paper were adhered to the spine edge and 3-5 smaller 15mm tabs of a lighter weight Japanese usumino paper were attached along the other three edges. For each tab, the edge in contact with the object was water-cut and then trimmed down with scissors.

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Fig. 4. Tabs of Japanese paper, with trimmed water-cut edges, for hinging the folios to the mounts.

The tabs were attached to the folios, with an overlap of less than 2mm, using wheat starch paste and left to dry underneath Bondina, blotting paper and small bag weights.

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Fig. 5. Attaching the Japanese paper tabs to the verso of each folio using wheat starch paste.

In terms of positioning, the two spine tabs were placed about 7mm from the bottom and top edges, to reduce the risk of the corners catching when the verso of each folio is viewed. In some cases, the position of these tabs needed to be shifted in order to avoid the red ruling lines.

The level of planar distortion varied from folio to folio, as the parchment not only had a memory of being in a bound volume but also the memory of being part of an animal skin! To account for this variation, the smaller tabs were positioned on a case-by-case basis, allowing each folio to lie as flat as possible whilst also allowing some movement. No more than 5 staggered paper tabs per folio were added, to reduce the risk of tensions arising and cockling.

2018_Composite_ImagesFig. 6. Folios 241 and 270 during treatment, showing the positions of the Japanese paper tabs.

Next, each pair of folios was positioned in their mount and the tabs on the spine edge were pasted to the back board of the mount. A Teflon folder was used to ensure a strong attachment.

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Fig. 7. Attaching the tabbed folios to the mounts using wheat starch paste.

Fig. 8

Fig. 8. Folios 294 and 295 after mounting.

The final stage in preparing these folios for exhibition involved framing the mounted miniatures in bespoke gold frames and then hanging them in the midnight blue temporary gallery, so the beautiful illuminations sparkled.

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Fig. 9. Framing the folios in the lab (left) and installing the exhibition (right).

Alice Derham, Conservation Intern

The Miniature Masterpiece: The Coëtivy Hours exhibition is on display from 9 March until 2 September 2018. We do hope you’ll come along to see it!

A lavishly illustrated catalogue by exhibition curator Dr Jill Unkel (Curator of the Western Collection), with contributions from Dr Laura Cleaver (Ussher Lecturer in Medieval Art at Trinity College Dublin), and our own Kristine Rose Beers (Senior Book Conservator), is available from the Library’s gift shop for anyone who wants to have an even closer look at the brilliance of this miniature masterpiece.