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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Yasha: A Traditional Japanese Paper Dyeing Technique

The Chester Beatty Library Conservation Department and the Restorient studio in Leiden have been working together closely for years. Andrew Thompson and Sydney Thomson at Restorient have conserved some of the collection’s most important Japanese scrolls and have been extremely generous in sharing some of their expertise with us. Thanks to them we discovered and have adopted the use of yasha, a traditional Japanese dye.

Yasha is the natural yellow-brown dye extracted from cones of the alder tree (Alnus japonica) and it has been used in Japan since the 8th century. In Japanese mounting studios, yasha is still used to dye the lining papers of hanging scrolls and hand scrolls. The light brown colour obtained from the dye helps to soften the white tone of the paper and silk used for linings and repairs.

Slide1

Preparation of  the yasha dye from Alnus japonica cones

Through centuries of practical application, the traditional use of yasha has proven its stability and durability which makes it highly suitable for conservation. Scientific studies confirm that papers dyed with yasha remain pH neutral or slightly alkaline, and retain their brightness and colour on ageing. Most plant dyes are light sensitive but yasha is lightfast, a quality which ensures its continued use.

Like many features of the traditional Japanese conservation studio, yasha is now readily available to Western conservators. With a growing interest in adapting conservation techniques imported from East Asia and Japan, the use of alder cones has become a known technique for dyeing paper when working on Japanese or Chinese Art objects.

The preparation of the dye and its application is straightforward.

Preparation

  1. Cover the bottom of a pot with alder cones and submerge them in water.
  2. Simmer for about 2 hours until the colour intensifies in tone.
  3. Once boiled, leave the dye to cool.
  4. Strain through a silkscreen or muslin cloth to remove impurities. The dye is now ready to use.

Application

  1. Cut a number of Japanese paper sheets of the same size.
  2. Pour the prepared dye into a shallow dish and apply directly to the rougher side of the paper with a large brush on a flat, non-porous surface.
  3. The brush strokes should be light and must follow the grain direction of the paper to avoid stretching the fibres. Each sheet is dyed individually; the dye is brushed on evenly and the surface of the sheet completely covered.
  4. The next sheet is laid on top of the last, staggered by 5mm. Repeat the process to ensure the dye is evenly applied to each piece of paper.
  5. When all the sheets are dyed, lay the stack on felt for 30 minutes to allow the water to begin to evaporate.
  6. After this short drying period the sheets are stronger and can be separated and left to dry fully on felt.

    Slide2

    Application of the dyestuff to handmade Japanese paper.

Fixing

  1. Rinse the dried sheets in cold water for no more than a few seconds as the dye is still fugitive and can be removed in water.
  2. Prepare a bath of water and Potassium Hydroxide (Potash). When the water reaches pH 7.1 rinse each sheet separately in the prepared bath to fix the dye onto the paper.
  3. Dry the sheets on felt before a final rinse in plain water to remove any excess lye (Potash).
  4. When dry, the sheets are ready to use.

    Slide3

    Fixing the dye, and the finished yasha-toned repair paper.

The process of layering the paper in a stack while applying the dye to each sheet of paper, creates a progressive darkening of tones throughout the stack from a light cream to a yellow-brown tone. The first sheet of paper to be dyed will be darkest in colour as the dye penetrates through the stack when subsequent sheets are dyed. The last sheet to be dyed when it is placed on top of the stack will be the lightest in colour, receiving only a single application of the dye.

As the dye is applied, it penetrates into the paper colouring the fibres internally. This is a major advantage when using this paper for repair as the water cut edge is the same colour as the toned surface. Unlike watercolour or acrylic paint solutions, where the application can leave visible brush strokes and tends not to fully penetrate the paper, yasha tones each sheet evenly, regardless of the size of the piece of paper.

Presentation1

A water-cut edge of yasha toned Japanese paper; and an Indian miniature (CBL In 11A.61) repaired using the prepared paper.

The gradation of colour obtained through the layering application technique is also extremely helpful to the conservator as it quickly produces a large quantity of paper dyed with various shades of a similar tone. The repair paper can then be used selectively to match the colour of a single sheet or for the repair of a full volume. The tones obtained from yasha are even and saturated, yet the paper remains soft and flexible and does not stiffen on drying. After fixing the dye no colour shift has been observed when repairs were applied.

The selection of different varieties of alder cones (both Japanese and European) and the preparation method described will achieve further useful colour variations and help the conservator to produce a large array of toned repair papers that can be kept on hand for use as necessary.

Slide2

The wide variety of tones that can be achieved using yasha.

The adoption of the Japanese dye yasha to tone repair papers at the Chester Beatty Library has been a success and we cannot recommend it warmly enough to colleagues. It is a wonderful method for dyeing paper and this readily available material certainly deserves to find its way into every conservation studio.

Julia Poirier, Book and Paper conservator

The Library is very grateful to Andrew and Sydney at Restorient for first introducing us to this versatile dyestuff when Julia undertook a short placement with them in 2013.

This work was first presented as a poster, ‘Yasha – Adapting a Traditional Japanese Paper Dyeing Technique to the Conservation of Parchment and Islamic Paper’ at the IADA conference ‘From Generation to Generation – Sharing Knowledge, Connecting People’ in Oslo, Norway 3-5 May 2017.