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Tru Vue Blog: Workshop on Asian Papers and their application in conservation

Amelia Rampton ACR specialises in the conservation of works of art on paper. Amelia received a Tru Vue Grant earlier in 2019 to enable her to attend the "Workshop on Asian Papers and their application in conservation" which took place at the British Library in June. 


This was a three-day workshop led by Minah Song, an independent conservator based in Washington DC, and it was hosted for the fifth time at the fantastic studios of the British Library Conservation Centre.

The course participants were very international, from Canada to India. The course laid emphasis on a deeper understanding of Asian papers and their use in Western paper conservation. The papermaking processes in China, Japan and Korea were clearly explained in lectures as well as in videos and the examination of samples.  Minah has travelled widely and has done extensive research on papermaking processes, especially in Japan and Korea.

minah_song_workshop_2019_0.jpg​​​Minah Song © 

The workshop kicked off with the history and characteristics of papermaking and the major paper fibres used in China, Japan and Korea. Among the fibres described at the course were: hemp, ramie, mitsumata, gampi, blue sandalwood, bamboo, straw and abaca.  A special emphasis was placed on paper mulberry, no doubt the most common fibre used in our practice (mulberry is described as ku, kou, chou in China, kozo in Japan and dak in Korea).

The papermaking making process was explained in detail.  After harvesting the plant, bundles of sprouts are steamed to soften the bark and remove it from its wooden core.  Then the black layer is removed, and the white bark is dried under the sunlight. Any black impurities left in the bark are removed manually (a job generally done by women). So, when one sees a perfectly clean handmade paper, free of any black specks, one knows it has gone through a hard-labouring process! The bark is then cooked in wood or soda ash (a good process) or in caustic soda, a strong alkali which is damaging to the fibre.  Finally, the fibre is beaten manually or with a beater (not cutting the fibre) and is ready to be used in sheet formation (with the addition of a formation aid).  After a sheet of paper is produced like this, it is pressed and then dried on wooden boards or heated plates.

Knowing the papermaking process is vital in understanding its influence on the pH, the colour, the thickness, the glossiness, the softness or crispiness, the opacity or translucency, the fibre distribution, the permanence and the strength of the paper.  To emphasise this, Minah gave us a series of Asian papers with a list of  the paper making processes, and our job was to identify which paper belonged to which process. Tengujo was the easiest paper to spot - it shows how popular it is in our work, but with the others we were more uncertain, though the weight gave some answers away. Handmade papers will feel denser than machine-made paper of the same weight. The samples of handmade Korean mulberry papers were of a very good quality and it was difficult to differentiate them from the Japanese papers. One Korean paper, No.1101 by Hyunse Shin in Korea (cooked with soda ash and dried in wooden boards) does not have clear chain lines and is slightly thicker than Tengujo, which is a perfect addition to our repertoire of papers. 

asian_papers_2_0.jpg​​​Amelia Rampton ACR ©

On the practical side, we started the sessions making a drying board out of honeycomb boards.  Most conservators are familiar with the Japanese Karibari drying board - these are fantastic structures made from a wooden lattice core and as many as seven layers of paper on both sides. But honeycomb boards can provide a lightweight rigid structure, can be as big as needed, and can be prepared in a fraction of the time.  To prepare a drying board, the honeycomb board was lined on both sides and the borders were covered with a machine-made Japanese paper. When the board was dry, it was coated with a Lascaux acrylic adhesive diluted in water, and it was ready for use. As with any new material and technique, practice makes perfect, and one needs to work on the speed of drying, which I thought might be too fast. But that can be controlled working in a not too dry environment or by placing a sheet of felt across the work to slow down the drying time.

We also practised ‘friction drying’, a very useful method when drying transparent papers, papers with distortions around the margins or moisture sensitive artworks. There are many small differences in the way this method is performed - Minah’s approach is to use mulberry paper as a drying support (rather than non-woven polyester materials), humidifying them separately and pressing them under blotters and weight.

We made small papers using mulberry and cotton fibres. In the paper mulberry fibre pulp, we added polyacrylamide, a synthetic formation aid to help with the dispersion of the fibres. A formation aid is vital to get an even distribution of fibres (it’s called totoroaoi in Japan, dakpool in Korea).  These papers were later used to do paper repairs.  Prior to paper repairs, we also toned papers with acrylic paints using a brush or an air brush. Both methods achieved a good result.  Other practical sessions involved linings with Japanese papers and diluted gluten free wheat starch paste, using remoistenable tissues to repair local tears. For the latter, samples of Japanese mulberry machine-made tissue 3.5 gm, were coated with the following combinations: 2% MC + wheat starch paste (1:1); another sample with 1.5% Klucel M in ethanol; and a third sample with 6% isinglass in DI water. The sample that seemed to work better for me, repairing a very damaged machine-made paper, was the isinglass activated with water.

These are only what for me were the highlights of the course – it was packed with useful information and the input from the participants always enhanced the experience. Minah has also given us a USB with photos from her research on identifying papermaking fibres as well as information about other work that has been done on the subject. It was a fantastic course and Minah Song is excellent at communicating her knowledge and experience to a large group of conservators who are at different stages of our careers.  I am very grateful to Tru Vue and Icon for sponsoring my attendance at the course.


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