Figuring out Folds: Conserving a Thai Buddhist manuscript

13 June, 2019

Tucked away in the Chester Beatty store is an important yet little known collection of Thai Buddhist manuscripts. The collection is one of the finest of its type in the world and includes manuscripts on palm and paper dating to the eighteenth and nineteenth centuries. For the past year and a half, the Chester Beatty conservation team have been preparing twenty-two large paper folding books from the collection for an exciting and colourful new temporary exhibition, Thai Buddhist Tales: Stories along the Path to Enlightenment(14 June 2019 – 27 January 2020).

Extracts of the Pali canon (Tipitaka) and Story of Phra Malai – a late 19th century Thai folding book (CBL Thi 1323).

Paper folding books (also known as samut khoi in Thai) were a popular type of Buddhist manuscript in central mainland Southeast Asia. They were often recited by Buddhist monks in religious ceremonies or used in temples as teaching aids. The thick and fibrous handmade paper used for samut khoi is usually made from the inner bark of the khoi tree (Streblus asper). To create a folding book, sheets of paper (up to 3m long) are glued together along the short edges to form one continuous sheet and then folded to make a concertina. The first and last pages are finished with lacquer to provide a protective cover. The text is usually written in black ink on both sides alongside striking illustrations in pigments and in some cases gold, to draw attention to particular sections of the text. In many cases the backgrounds of each illustration are elaborately decorated with ornate patterns (to find out more – take a look at this blog post from the British Library).

Whilst typically in good condition, a number of the samut khoi at the Chester Beatty had suffered damage, including detaching lacquer covers, delamination and breakage along the folds, as well as flaking and powdering of pigments. One of the manuscripts (CBL Thi 1314) was in very poor condition, as a result of previous water damage and handling. It needed extensive conservation to prevent any further damage and ensure it could be safely displayed.

Story of Phra Malai – a late 18th century Thai folding book (CBL Thi 1314) before conservation.

Story of Phra Malai – a late 18th century Thai folding book (CBL Thi 1314) before conservation.

This manuscript, dated 1795, tells the story of a Buddhist monk, Phra Malai, who visited heaven and hell through the power of meditation and then shared tales from his travels on his return to Earth.

Important passages of the text have been written in gold paint on striking red, orange, black and green backgrounds, indicating that this is a prestigious Buddhist manuscript. Curiously, but not unusually, the illustrations do not relate to the text and instead depict scenes of Buddha and his last ten lives.

Water damage extending inwards from the sides of the text block, in combination with poor handling and storage, had made it incredibly difficult to handle the manuscript safely. There were a large number of tears along the folded edges and the paper was weak and delaminating in some areas. The lower cover was missing and the upper cover was severely damaged with large losses at the edges and cracks in the lacquer coating. Inappropriate sewn repairs along several of the torn folded edges had caused misalignment of the text block and several of the openings were restricted and at risk of tearing. The pigment was severely abraded and there were some instances of localised flaking of the white and gold pigment, as well as powdering of the red and black pigments.

Detail showing cracks in the lacquer coating on the upper cover.

Historic sewn repair along a join between two separate sheets of paper in the textblock.

Misaligned text block due to sewn repairs.

Restricted opening due to a sewn repair.

First of all the exterior of the manuscript was treated. Wheat starch paste was used to repair the delaminating paper and lifting lacquer on the cover, as well as the detaching media along the folded edges. After thorough documentation, the sewing was carefully removed from all folds where there was a risk of further damage. With the text block now in three separate parts, the repairs could be carried out more easily.

Consolidating the detaching media along the folded edges with wheat starch paste.

Removing the sewn repairs.

The losses in the cover and tears along the folds were repaired with acrylic-toned Japanese paper and wheat starch paste using a double-layer method that would ensure sufficient support. Acrylic-toned sekishu paper was water-torn to fit the shape of each loss/tear and adhered to the outside of each torn fold to give structural support, except in cases where media was present. On the reverse of each repair, thin acrylic-toned tengujo paper was adhered to add strength and secure any fragile paper edges. The weak and abraded paper on the left and right edges of the text block were strengthened with tengujo paper and wheat starch paste.

Repairing tears along the folded edges with sekishu paper.

Strengthening the weak and abraded paper edges with tengujo paper and wheat starch paste.

For the large tears and losses, small Japanese paper splints were attached using wheat starch paste, to hold the folds in the correct position during repair. This was a particularly challenging part of the treatment. The splints were positioned with the manuscript lying flat, but many needed to be adjusted to ensure that the finished repairs would not protrude from the edges of the text block.

Japanese paper splints attached to the inside of a broken fold.

Repairing the outside of the fold with sekishu paper, over a light box.

Repairing the inside of the fold with tengujo paper.

Small Japanese paper splints along the folded edges.

Finally the repairs were trimmed down and the three parts of the text block were joined together in correct alignment. Each join was splinted as necessary and then joined together using the existing paper overlaps or the same double-layer method described above.

Joining separate parts of the text block together using an existing paper overlap.

Finally, pigment consolidation was carried out to re-adhere any loose areas of pigment  to the paper below. The flaking white and gold pigments were consolidated using a 2% aqueous solution of Bermocoll® (a cellulose-based adhesive) applied with a brush under magnification. The powdery pigments were stabilised by applying 0.5% aqueous solution of Bermocoll® as a mist, using a nebuliser. With the conservation treatment complete, the manuscript could be handled safely and the toned paper repairs blended sympathetically with the object.

CBL Thi 1314 after conservation.

CBL Thi 1314 after conservation.

Similar methods were used to repair torn folds and stabilise media on other folding manuscripts in the collection. After conservation the manuscripts were fully digitised and carefully measured for bespoke Perspex® cradles.The exhibition planning and conservation was a real team effort and involved the whole conservation team, including Juliet Baines (summer placement student), Julia Poirier, Adam Macklin and Kristine Rose-Beers.

Stabilising powdery pigments with 0.5% Bermocoll applied using a nebuliser (CBL Thi 1356).

Securing CBL Thi 1318 to a Perspex® cradle, on top of a Thai lacquered box (CBL Thi 1364).

CBL Thi 1318 supported by a Perspex® cradle, on top of a Thai lacquered box (CBL Thi 1364).

CBL Thi 1314 and other delightful manuscripts from the Thai collection will be on display at the Chester Beatty in the temporary exhibition ‘Thai Buddhist Tales: Stories along the Path to Enlightenment’ (14 June 2019 – 27 January 2020)

Alice Derham will give a talk to the Friends and Members of the Chester Beatty on Friday 5th July, sharing her experience of conserving these intriguing manuscripts in more detail. If you are interested in becoming a Friend of the Chester Beatty you can find out more here.

This work was first presented as a poster, ‘Figuring out Folds: Conserving the Structural Integrity of a Thai Manuscript’ at The Institute of Conservator-Restorers in Ireland (ICRI) conference – ‘Conservation Activities in Ireland VI’, held at the National Gallery of Ireland, 4 October 2018.


The exhibition is supported by The Robert H. N. Ho Family Foundation.

Closed today

Tuesday to Friday 10am–5pm
Saturday 11am–5pm
Sunday 1pm–5pm

Closed Mondays: Nov - Feb

**Closed 1 Jan; Good Friday; 24-26 Dec & Monday Public Holidays.**

Admission is free
Suggested donation €5


Chester Beatty
Dublin Castle
Dublin 2
D02 AD92