« No need for Magic: A simple trick for the display of a Batak manuscript » by Julia Poirier, 13/07/2018, Chester Beatty Conservation
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.
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.