Door Thomas Brain
The course Asian Paper was given by Minah Song, an independent conservator of art on paper and archive material who trained in London and Korea and is now based in Washington D.C. She speaks regularly about Asian paper and the evaluation of their quality for use in conservation including a presentation at the 2015 Adapt and Evolve Conference in London. The course location was the Leidse Lente: a former school now a creative studio complex and café. The twelve participating book and paper conservators, had travelled from the UK, Ireland, Belgium, Italy, Kenya and India as well as the Netherlands. Over three days the background about papermaking in various Asian countries was introduced with many illustrations, videos and much insider knowledge. Lists of tools and materials were sent in advance including instructions how to construct a pressing board using blotting paper, Hollytex (nonwoven polyster) and mounting board. The emphasis was placed on practical exercises to actually experience the papermaking process and the application of Asian paper in different conservation techniques. The aim of the course was to deepen the understanding of Asian paper and to avoid the mystification or fantasy that sometimes surrounds it. Through a better understanding, it becomes possible to use the papers, without prejudice, to solve conservation problems.
A powerpoint presentation introduced the subject matter starting with the oldest piece of paper known, a fragment of a map on hemp paper from the Dunhuan archaeological site (PRC) continuing through the development of paper making in China, Korea and Japan. Fibre sources were discussed including the distinction between mulberry and paper mulberry. The paper mulberry found all over Korea is called Chamdak or just dak. Other fibres discussed were bamboo, blue sandalwood and rice straw (China), abaca (a.k.a manila hemp), mitsumata and gampi (Japan) and elephant dung (Thailand). Although there are a number of plants that are suitable for papermaking the choice is ultimately restricted to what is local. Certain areas become known for one particular type of paper, such as the Mino area in Japan and the Anhui province in China where Xuan paper is made. Water is of great importance to the process and the best quality paper comes from mountainous areas where the water is abundant and uncontaminated. Videos illustrated the crops of paper mulberry being collected, the painstaking process of steaming the bundles of branches, the stripping away of the bark, the removal of the dark outer bark and the process of cooking in alkali, beating, washing, bleaching and purifying of the pulp before it can be made into sheets.
Sheet forming was discussed in its many forms. The simplest method involves scooping or pouring the prepared pulp on a mould and forming a sheet in one draining action. The sheet is then left to dry on the mould. This was the way that paper was first formed in China and the technique is still used but it will not produce the thin, translucent and impurity free paper that is of interest to conservators. The method called Webaltteugi in Korea uses a flexible bamboo screen that can be removed from the mould once a thin layer of pulp has been deposited on it in a process of scooping, swishing and shaking. The oblong frame is suspended above the vat with a rope at one end and the papermaker at the other end facing the shorter end of the frame. A similar technique is used for xuan paper (China) but with two papermakers one at each end of the frame. Generally in Asia there is no interleaving of the individual wet sheets although a thread is laid down to help separate them. The bamboo screen is removed from the frame and laid on the wet pile of paper already formed and is peeled away leaving the paper behind on the wet pile. After pressing to remove excess water, the damp sheets are separated and dried. The second method in Korea, called ssangbaltteugi, also uses a removable bamboo screen but this has a hinged frame with elevated edges that will hold the water with the pulp within the frame for a longer time to be manipulated by the papermaker. This technique was imported to Korea from Japan where is it called nagashizuki. The papermaker stands facing the longer edge of the frame holding onto two handles on the hinged cover.
The way the sheets are dried, on a screen in the air, on a wooden board or on a heated metal surface, will also influence the look and feel of the finished product. A finishing process in Korea called Dochim is the pounding of the paper with a wooden hammer or bats. This makes the paper surface more compact preventing ink from spreading out too quickly when applied with a brush. Not surprisingly Hanji or Korean paper has the nickname baekji meaning the paper of 100 touches referring to the lengthy production process. After this presentation the participants were put to the test to match up 15 samples of Asian paper with their corresponding description.
As the first practical exercise a drying board for flattening paper was constructed using acid-free honeycomb board (Klug), covered on both sides with a layer of mulberry paper adhered with thin wheat starch paste and later coated with acrylic dispersion adhesive (Lascaux 489HV, diluted with water 1:1). The acrylic acts as a release layer for the margins when a sheet is stretched up on the board. The honeycomb board is 13 mm thick and a slight warping is noticeable after is has been covered however this will not impede the functioning of the board. A sheet of thin Hollytex is inserted behind the work to prevent it sticking to the board. As with the Japanese kari bari-technique a strip of dry paper is inserted under one of the margins to assist with the release of the sheet. In China the fascination with kari bari is not shared and there any flat surface or wall will be used to stretch and flatten paper.
The friction drying technique for flattening paper was demonstrated whereby a humidified object was placed between two dampened sheets of mulberry paper and allowed to dry weighted between blotters for a number of days. This method is recommended for particularly moisture sensitive papers such as tracing paper. For this exercise the dummy drawings were humidified using sympatex. The moisture was sprayed onto the fluffy side of the sympatex before the drawings were placed onto the shiny side, covered with more sympatex, which is again sprayed on the fluffy side and covered to allow the moisture to slowly humidify the drawings.
A demonstration of papermaking followed, using cotton and recycled rag paper fibres in one vat and paper mulberry fibres in a second vat. The mulberry fibre was mixed with a synthetic formation aid (polyacrylamide, PAM) which has a slimy feel to the touch and forms strings when lifted out of the water. This aids the even distribution of the fibres in the water and prevents them from sticking together in clumps. The formation aid also influences the speed at which water will drain away through the mould during sheet formation. A high proportion of formation aid means slow drainage and the resultant paper is thinner and stronger. A lower proportion of formation aid means faster drainage and a thicker but less strong sheet. Small circular embroidery frames were used to hold a piece of polyester fabric taut forming a papermaking frame. A white cloth Tekwipe/ Texwipe (55% cellulose hydrospun and 45% polyester) was used to couch the paper and also to press the water out.
Toning of paper using (Golden®) fluid acrylic paints followed including tips about methods of application that will not disturb a delicate paper surface such as air brush. The toned sheets were hung up to dry using small strips of melinex as a hanger. A final practical session for the day concerned the application of adhesives, Klucel M in ethanol and Wheat Starch mixed with Methyl Cellulose to machine made Japanese paper mulberry 3.5-4 gsm on melinex to form pre-coated tissues for repair work. Klucel M has a higher viscosity than Klucel G making it a stronger adhesive.
At the end of the day an excursion to the Leiden University Library was hosted by Karin Scheper a conservator specialised in Islamic manuscripts. Manuscripts with Persian, Chinese, Japanese and European origin were examined by the group. One volume was written on dluwang, a Javanese word for sheets of bast fibre produced purely by beating.
Minah’s second powerpoint highlighted the way the different steps in the paper making can influence the various qualities of paper including, strength, thickness, colour, permanence, transparency and surface structure. These are the qualities that will influence the suitability of the paper for a particular conservation application. And they also influence the price. A diagram was used to show the chain of commerce that brings the paper from the makers, to the middle men, to the suppliers and eventually to the conservator. Within this chain there is room for misunderstanding and lack of communication but Minah stressed the importance of continuing to ask questions to your suppliers. The more it is known that the Asian papers are appreciated the better the chance that the traditional papermakers will continue in the future.
The rest of the day was used to practise on dummies: applying repairs; coloured fills and linings; flattening on the drying board; applying a double sided lining using a tinted tissue and the application of the pre-coated tissues using minimal amounts of moisture. A non woven fabric Evolon, (70% polyester and 30 % polyamide microfibers) can be used as a moisture reservoir to reactivate the adhesive on the pre-coated tissues. During double sided lining the ultra fine Japanese paper (4g) was applied directly to the relaxed object first and then the thin wheat starch paste was applied on top, brushed through a thin sheet of Hollytex.
Minah is an advocate for the use of Hollytex, as a support during wet treatment but also as a protective layer to brush moisture through onto fragile paper that will not withstand the friction of a brush. As a support for lining papers it is more easily removed from wet pasted layers than melinex. Being not so transparent it is necessary to mark it with pencil to indicate where the edges of a pasted lining paper are to allow for good registration.
Another valuable tip was the use of Mitsumata paper to fill losses in western paper. The technique involves applying a relatively thin lining paper to the reverse of the area to be filled using wheat starch. A thicker paste is then applied to the lining paper visible through the missing area on the front. A piece of toned Mitsumata paper, not yet specifically shaped, is then applied over the paste and rubbed down with a bone folder or a Teflon spatuala on the back and allowed to dry. The edges of the Mitsumata are then teased up and cut away from the surface using a small round scalpel. The resulting edge matches the area of the loss without any overlap. By varying the number of the layers,
the toning and the thickness of the paper it becomes possible to imitate the western paper closely. These fills can be more imperceptible than western repair papers and may also be carried out with more accuracy and speed.
The course was very thoroughly prepared and was able to introduce a complex subject and make it accessible without intimidating. The presentations and demonstrations had a logical order making them very enjoyable to follow. Much of the material was summarised in a hand-out including a bibliography and at every juncture samples were given of the materials being discussed.
There was a good balance between theory and practical work. Generous time devoted to the practical exercises allowing for experimentation and learning from mistakes. The demonstration of Joomchi, a traditional Korean felting technique using brightly coloured paper, was fun and allowed a break from the concentration needed for the theory. My favourite technique was the double sided lining. Seeing a technique that one would not normally do, work beautifully, is the best learning experience.
Many thanks are due to Eliza Jacobi for the smooth organisation, to Wieslaw Rzadek for the preparation behind the scenes and to Minah for her well structured and generous teaching.