Amongst the treasures at the Chester Beatty is a small collection of 51 Batak manuscripts – 45 bark books, 4 inscribed bamboos, 1 bone amulet and one paper manuscript. Hailing from North Sumatra in Indonesia, the oldest of these manuscripts is dated to the 19th century. The Batak manuscript culture encompasses written texts on various organic materials including bamboo, bone and tree bark. The bark books, also known as pustaha are divination books, although other subjects such as medicine and magic are also common.
Right: CBL Sum 1144, a small size bark concertina manuscript held closed with a band of plaited rattan; Left: CBL Sum 1147, an inscribed bamboo rod
In preparation for a rotation of the Batak display case in the Sacred Traditions gallery, I condition checked four bark manuscripts. They were all in good condition and required very little attention, with the exception of one object (CBL Sum 1102).
The bark concertina manuscripts vary in size from some which are small enough to fit in the palm of your hand, to others which are around A4 in size. They are made of two wooden covers glued to a folded textblock made from the bark of the alim tree or agarwood. The stiff bark is prepared in rice water to allow it to soften and be folded into a concertina book.
In the typical East Asian fashion, lacquer was used to seal off the raw edges of the bark at head and tail of the concertina textblock. This provided extra strength to the most vulnerable part of the exposed textblock.
Inside the textblock, the text runs vertically in plain black ink, following the folds in the concertina. There are additions of elaborate illustrations and tables within the text, sometimes highlighted in red ink.
CBL Sum 1129 open textblock
The wooden covers of the Batak manuscripts are sometimes decorated with hand-carving, and always carefully cut to the size of the manuscript or left slightly larger to provide a square which would protect the textblock. To hold the concertina books and their wooden covers together when closed, a band of plaited rattan or sometimes leather is used.
On many examples, handle straps are attached to the upper cover of the larger books. They are made of a dark coarse material, probably tree fibres of the sugar-palm, and roped together to create a handle. This enabled the owner of the manuscript to transport them from site to site and also to store the book on the wall, away from rodents and moisture.
On manuscript CBL Sum 1102, the sugar-palm fibre straps on the manuscript upper board were bent down and had lost their 3-dimensional aspect. As the curator wanted the object to be displayed closed, with the straps held up to give some context to the object and meaning to the straps, we needed to find a solution to support the misshapen straps, as invisibly as possible.
CBL Sum 1102 with sugar-palm straps bent down
The use of a Perspex or brass rod support underneath the strap was considered and a few unsuccessful ideas were tried out such as Melinex supports, manipulation of the straps and humidification, I decided to go back to basics.
Using a simple thread which was attached to the strap on one side and to the display case fabric on the other, I hoped that the strap would stay in place. Luckily for us, the bend in the strap was facing away from the back of the case. This meant that with a very simple low-tech thread the same colour as the fabric lining the case, I could pull the strap in to place using enough tension to pull it up for the duration of the display. In a worst case scenario, the thread would give way well before any damage to the palm fibres occurred and would only lead to the handle coming back in to its bent position.
Display of CBL Sum 1102 with straps help up using silk thread
I used an extremely fine 100% orange silk thread which I looped around the book cover handle and into the fabric at the very top of the case and knotting it to itself. The system is extremely discreet and after a few months of display, the thread has held and I am happy to say that the handle is still standing!
CBL Sum 1102 on display with straps held upright
Working on the display of the Batak manuscripts was extremely rewarding. Problem solving is what conservators love best and I was happy to be able to use a simple, low-tech solution for the display of this manuscript. It is sometimes all you need.
If you want to learn more about Batak manuscripts, I recommend you read this great article by René Teygeler.
Julia Poirier – Book conservator