Yasha: A Traditional Japanese Paper Dyeing Technique

The Chester Beatty Library Conservation Department and the Restorient studio in Leiden have been working together closely for years. Andrew Thompson and Sydney Thomson at Restorient have conserved some of the collection’s most important Japanese scrolls and have been extremely generous in sharing some of their expertise with us. Thanks to them we discovered and have adopted the use of yasha, a traditional Japanese dye.

Yasha is the natural yellow-brown dye extracted from cones of the alder tree (Alnus japonica) and it has been used in Japan since the 8th century. In Japanese mounting studios, yasha is still used to dye the lining papers of hanging scrolls and hand scrolls. The light brown colour obtained from the dye helps to soften the white tone of the paper and silk used for linings and repairs.

Slide1

Preparation of  the yasha dye from Alnus japonica cones

Through centuries of practical application, the traditional use of yasha has proven its stability and durability which makes it highly suitable for conservation. Scientific studies confirm that papers dyed with yasha remain pH neutral or slightly alkaline, and retain their brightness and colour on ageing. Most plant dyes are light sensitive but yasha is lightfast, a quality which ensures its continued use.

Like many features of the traditional Japanese conservation studio, yasha is now readily available to Western conservators. With a growing interest in adapting conservation techniques imported from East Asia and Japan, the use of alder cones has become a known technique for dyeing paper when working on Japanese or Chinese Art objects.

The preparation of the dye and its application is straightforward.

Preparation

  1. Cover the bottom of a pot with alder cones and submerge them in water.
  2. Simmer for about 2 hours until the colour intensifies in tone.
  3. Once boiled, leave the dye to cool.
  4. Strain through a silkscreen or muslin cloth to remove impurities. The dye is now ready to use.

Application

  1. Cut a number of Japanese paper sheets of the same size.
  2. Pour the prepared dye into a shallow dish and apply directly to the rougher side of the paper with a large brush on a flat, non-porous surface.
  3. The brush strokes should be light and must follow the grain direction of the paper to avoid stretching the fibres. Each sheet is dyed individually; the dye is brushed on evenly and the surface of the sheet completely covered.
  4. The next sheet is laid on top of the last, staggered by 5mm. Repeat the process to ensure the dye is evenly applied to each piece of paper.
  5. When all the sheets are dyed, lay the stack on felt for 30 minutes to allow the water to begin to evaporate.
  6. After this short drying period the sheets are stronger and can be separated and left to dry fully on felt.

    Slide2

    Application of the dyestuff to handmade Japanese paper.

Fixing

  1. Rinse the dried sheets in cold water for no more than a few seconds as the dye is still fugitive and can be removed in water.
  2. Prepare a bath of water and Potassium Hydroxide (Potash). When the water reaches pH 7.1 rinse each sheet separately in the prepared bath to fix the dye onto the paper.
  3. Dry the sheets on felt before a final rinse in plain water to remove any excess lye (Potash).
  4. When dry, the sheets are ready to use.

    Slide3

    Fixing the dye, and the finished yasha-toned repair paper.

The process of layering the paper in a stack while applying the dye to each sheet of paper, creates a progressive darkening of tones throughout the stack from a light cream to a yellow-brown tone. The first sheet of paper to be dyed will be darkest in colour as the dye penetrates through the stack when subsequent sheets are dyed. The last sheet to be dyed when it is placed on top of the stack will be the lightest in colour, receiving only a single application of the dye.

As the dye is applied, it penetrates into the paper colouring the fibres internally. This is a major advantage when using this paper for repair as the water cut edge is the same colour as the toned surface. Unlike watercolour or acrylic paint solutions, where the application can leave visible brush strokes and tends not to fully penetrate the paper, yasha tones each sheet evenly, regardless of the size of the piece of paper.

Presentation1

A water-cut edge of yasha toned Japanese paper; and an Indian miniature (CBL In 11A.61) repaired using the prepared paper.

The gradation of colour obtained through the layering application technique is also extremely helpful to the conservator as it quickly produces a large quantity of paper dyed with various shades of a similar tone. The repair paper can then be used selectively to match the colour of a single sheet or for the repair of a full volume. The tones obtained from yasha are even and saturated, yet the paper remains soft and flexible and does not stiffen on drying. After fixing the dye no colour shift has been observed when repairs were applied.

The selection of different varieties of alder cones (both Japanese and European) and the preparation method described will achieve further useful colour variations and help the conservator to produce a large array of toned repair papers that can be kept on hand for use as necessary.

Slide2

The wide variety of tones that can be achieved using yasha.

The adoption of the Japanese dye yasha to tone repair papers at the Chester Beatty Library has been a success and we cannot recommend it warmly enough to colleagues. It is a wonderful method for dyeing paper and this readily available material certainly deserves to find its way into every conservation studio.

Julia Poirier, Book and Paper conservator

The Library is very grateful to Andrew and Sydney at Restorient for first introducing us to this versatile dyestuff when Julia undertook a short placement with them in 2013.

This work was first presented as a poster, ‘Yasha – Adapting a Traditional Japanese Paper Dyeing Technique to the Conservation of Parchment and Islamic Paper’ at the IADA conference ‘From Generation to Generation – Sharing Knowledge, Connecting People’ in Oslo, Norway 3-5 May 2017.

Advertisements

Conservation through generations

 

Oslo Harbour

Oslo Harbour.

Between the 3rd and 5th of May the International Association of Book and Paper Conservators (IADA) hosted their 2017 symposium, ‘From Generation to Generation – Sharing Knowledge, Connecting People,’ at the Oslo Konserthus in Norway, a wonderful modern building in the heart of this capital city.

Slide2

Elizabeth Randell speaking about her experience as an intern at the Chester Beatty and The Oslo Konserthus.

The conference was aimed at exploring the way knowledge and skills are passed on and shared with younger generations of conservators, looking at various teaching programmes worldwide, social media and academic writing amongst other subjects. The conference also focused on practical work, challenges linked to treatments, and our ability as conservators to reflect as we adapt past techniques and create new practices.

I was delighted to be given the opportunity to present a research poster on the use and adaptation of yasha at the Chester Beatty Library. Yasha is a natural dye obtained from the cones of the alder tree, which was first introduced to me by the two wonderful conservators, Andrew Thompson and Sydney Thomson, at the Restorient Studio, in Leiden in The Netherlands.

Slide1

Repairs for CBL Heb 751 toned with Yasha (left); harvested yasha cones (right).

In Japanese mounting studios yasha is used to dye the lining papers of both hanging and hand scrolls. The light brown colour obtained from yasha helps to soften the bright white tone of the lining paper and silk so that it is more sympathetic to the delicate tones of historic objects.

Through centuries of practical application, the traditional use of yasha has proven stability and durability which makes it suitable for conservation. Papers dyed with yasha remain pH neutral or slightly alkaline and retain their brightness and colour on ageing.Most plant dyes are light sensitive but yasha is lightfast.2 It continues to be used today for these qualities.
Like many features of the traditional Japanese conservation studio, yasha is now readily available to Western conservators. With a growing interest in adapting conservation techniques imported from East Asia and Japan, the use of alder cones has become a known technique for dyeing paper when working on Japanese or Chinese Art objects. However, its use has rarely been developed outside of this small circle.

JP presenting poster

Julia introducing her poster to attendees.

At the conference, the poster session took place on Thursday for over an hour after lunch, when attendees had the opportunity to ask questions about the research presented. I was delighted with the interest the research sparked and feedback I got from different conservators. Some had used the dye previously but were excited to hear about different application techniques, others were keen to be introduced to it and the ways to adapt its use to best suit our practice.

The conference finished with Friday visits organised at various institutions throughout the city, looking at the wonderful conservation work going on in Oslo!

Overall the two day conference was immensely varied and interesting to conservators of all generations who hopefully have learned from each other. The beautiful tributes to the important role of mentoring, teaching and sharing that Christopher Clarkson and Fred Bearman have played in the short history of conservation felt very appropriate with the overall topic of the conference. They will be sadly missed as pioneers and mentors to many.

Aurlandsfjorden

Aurlandsfjorden.

After the conference I took the opportunity to travel to Bergen. Norway is a stunning country and I was delighted to see some of the beautiful scenery, including these most amazing fjords along the way!

 

 

Julia Poirier,  Book and Paper Conservator

 

1 – Yeh, Brigitte. Munn, Jesse (2003) ‘An Evaluation of Xuan Paper Permanence and Discussion of Historical Chinese Paper Materials’ from ‘Scientific Research on the Pictorial Arts of Asia’. Edited by Paul Jett et al. Proceedings of the Second Forbes Symposium at the Freer Gallery, Washington DC, USA.

2 – Grantham, Sandra; Webber, Pauline, (2002) ‘Mellow yellow: toning papers with traditional Far Eastern colourants’, The Paper Conservator, Vol.26, pp. 49-57.