Content
Introduction
As mentioned before, the state of conservation of the paintings is very good in those areas that have not been exposed to external damaging factors. That means that extensive conservation measures like a complete fixation of the paint layer or a protective coating would not be appropriate here. One should think, though, about protective measures for the lower wall areas that have been damaged by temple visitors and will continue to be endangered by the exposure to people visiting the temple.
The state of conservation of the sculptures is good in those areas that have not been exposed to external damaging factors. These factors are above all whirled up dust and dirt, the soot of the butter lamps and mechanical stress on protruding sculptural parts. As these damaging factors go along with the religious use of the temple, they can’t be prevented. The conservation team however is in dialogue with the users to find ways to prevent as much damage as possible.
After we had taken stock of the conservation status and the different damage phenomena had been examined, we then tested the conservation materials and techniques. Once the methods were determined, the most endangered areas in the temple are secured, particularly in the upper zones around the beam heads and the gaping cracks in the corner areas near the outward leaning east wall. The conservation work is then carried out section by section, starting with the most severely damaged areas (southerly east wall and south wall). The conservation work varies in its sequence depending on the nature of the damages.
Further considerations and measures taken to complement missing pieces of paintings and to complement damaged or reduced areas of painting are presented and discussed in section Restoration.
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Conservation Methods
The main conservation problems of the paintings relate to the removal of loam streaks which cover the largely damaged paintings and to the stabilisation of endangered zones by filling the lacunae with loam putty and by flattening and fixing the flaking paint layer. Various tests were carried out to cope with these problems. The main problem areas are encountered on the southern part of the east wall and on the south wall. Although the paint is soluble in water, the painting can be cleaned by using very little water, and by allowing enough time to pass, before re-applying water.
The main conservation problems of the sculptures relate to the removal of dust, dirt and soot which have at least partly infiltrated the paint layer. The second problem is the handling of the damaged sculptural parts. On the one hand there are broken elements which have to be re-fixed, then there are losses which might have to be supplemented and there are older replacements which bear the question of whether they should be left in place even if they were executed in a more crude manner.
Having concluded our examinations and preliminary tests and having gained first application experiences in the two working periods in 2000/2001 (painting) and 2005/2006 (sculptures), conservation and restoration measures were developed, as outlined below. Their sequence may vary according to the type of damage encountered.
- Careful removal of loose dirt from the surface of the painting with soft paint brushes.
- Mechanical reduction/removal of loam streaks and lime splashes from the painting (scalpel, wooden sticks, bristle brushes) followed by cleaning the surface with cotton swabs and a mixture of water and alcohol.
- Reduction of whitewash film (lime) with cotton swabs and water or a mixture of Methylethylketon, water and alcohol.
- Mechanical removal of whitewash (lime) splashes, followed by cleaning operation with a mixture of water and alcohol.
- Fixing/consolidation of flaking paint layer which, together with the white prime coating, is detached from the fine layer of plaster. A binding medium, based on cellulose, is used for this purpose. The affected areas are first dampened with a mixture of ethyl alcohol and water which serves to revive the anchoring property of the earth. Then we lightly press the flakes back to their original position with the help of a non adhesive film and cotton wool.
- Stabilizing of smaller hollow areas by injecting a mixture of cellulose and fine markalag clay. Same procedure as described under point 5.
- Filling the lacunae and cracks. Several layers may be necessary depending on the size and depth of the gaps and cracks. The filling material is made of earthen mortar (markalag or mixture of markalag and sand). The filling is then covered with a pigmented, liquid layer of markalag to which we add a binding medium made of cellulose. This liquid clay layer consolidates the slightly powdery surface of the fillings and can also be fitted into the general colouring scheme of the surrounding area.
- The large plaster gaps, mainly visible at the floor base up to a height of about 50 cm, are filled with earthen putty (adobe brick material, markalag, sand and/or pebbles and/or straw) in order to protect the adjoining regions of the painting. Subsequently, a layer of pigmented, liquid markalag enriched with cellulose acting as binding agent, is applied onto the filling material. This material also serves to blend into the same colouring as the surrounding area.
Materials
- River sand
- Straw, plant fibres
- Local earth used for the production of adobe bricks
- markalag: fine clay from two quarries near Kanji and near the Monastery of Spituk used in traditional building technique for the priming of the wall surfaces.
- Ethanol
- Methylethylketon
- Tylose MH 300© and Tylose MH1000©
- Hostaphan© film
- Scalpel, wooden sticks, bristle brushes, cotton wool, foam rubber sponges
Recipes
- Mixture of water/Ethanol in the percentage of 3 : 1 for cleaning and dampening for subsequent fixing and consolidating of paint layer and filling of lacunae.
- Mixture of Methylethylketon, water and alcohol in the percentage 2: 1: 1 for the reduction of whitewash film.
- 5% Tylose© in a mixture of water and ethanol for fixing and consolidating of paint layer.
- 5% Tylose© in a mixture of water and ethanol with an addition of markalag to stabilize smaller hollow areas. This material is also used to prime and colour the fillings.
- Markalag for the surface layer of fillings, markalag and sand in a proportion varying from 1 : 1 to 1 : 2 for filling of lacunae and cracks.
- Earthen putty (adobe brick material or markalag with sand and pebbles and straw) for the large plaster gaps.
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Wooden Elements
As pointed out above (see condition of the interior), most of the wood which was exposed for a long time to outdoor conditions is damaged or has a corroded surface. The door additionally shows physiological wearing away. The original parts of the ceiling of the interior temple instead show contamination of soot, dust and loam and water marks, whereas the fragmentary preserved polychrome painting on the brackets has lost its cohesion and adhesion to the wooden support.
With reference to these damages there have been executed various cleaning and consolidation tests. Conservation measures were developed, as outlined below. Their sequence may vary according to the type of damage encountered:
Coloured brackets and ceiling boards
- Removal of loose dirt with soft brush.
- Consolidation of incohesive (powdering) paint layer with scotch glue (0,5% glue in alcohol/water). This has to be done before the cleaning, to avoid further loss of paint.
- Fixation of flaking paint layer with scotch glue (2% glue in alcohol/water) with the help of a non adhesive film and cotton wool. This has to be done before the cleaning, to avoid further loss of paint.
- Cleaning of all surfaces with Wish-ab® sponges.
- Removal of loam streaks with scalpel.
- Final cleaning with slightly moist sponge and several types of brushes.
- Protective coating with cellulose (1% Tylose© in water).
Door
- Reinforcement of the crossbars with wooden wedges.
- Adhesive gluing of crossbars with scotch glue (10% in water/alcohol).
- Surface cleaning with Wish-ab® sponges.
- Removal of loam streaks and adhesive dirt with scalpel.
- Final cleaning with slightly moist sponge and several types of brushes.
- Protective coating with cellulose (1% Tylose© in water).
- Repair and mounting of the door hinge.
Materials
- Ethanol
- Tylose MH 300© and Tylose MH1000©
- Hostaphan© film
- Wa-shi (japanese paper)
- Scotch glue
- Foam rubber sponge
- Scalpel, wooden sticks, bristle brushes, cotton wool
- Injection tools
Recipes
- Consolidation of incohesive (powdering) paint layer with scotch glue (0,5% glue in alcohol/ water).
- 0,5% scotch glue in water/Ethanol sprayed upon the surface for the consolidation of powdering paint layer.
- 2% scotch glue in water/Ethanol injected under paint flakes which afterwards are put down in their original position with the help of Wa-shi, Hostaphan© film and cotton wool swabs.
- 5% Tylose© in a mixture of water and ethanol for fixing and consolidating of paint layer
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Conservation Measures per year
September 2000
by Barbara Sedlaczek, Martina Oeter and Steven Post
In the first phase of our conservation and restoration project, we made a detailed assessment of the damage showing on the four walls of the temple. In the next step, we identified the different types of damage and chose for each type a sample area in order to develop appropriate working methods.
1) South wall, east section
Here, the paint layer was detached from the underlying layer of fine loam plaster. Our work concentrated on developing a suitable fixation material.
As an interim measure, water seemed to be a satisfactory fixation medium. We tried various consolidation alternatives and finally decided on the following approach: dampening the surface with a solution of ethyl alcohol and water to revive the anchoring properties of the loam plaster. Larger flakes of the paint layer had to be fixed additionally with a binding medium. The best of all tested materials was cellulose.
2) South wall, west section
This area was chosen in order to test different surface cleaning methods such as for removing dust, reducing the loam streaks and the lime splashes.
- Removed dust.
- Removed loam streaks and lime splashes. The loam streaks and lime splashes were reduced, but the painting underneath the dirt was damaged because humidity had been prevalent for too long a time.
- Filled up lacunae.
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July/August 2001
by Barbara Sedlaczek and Alexandra Stajkoski
During this phase, various areas showing different types of damage were chosen to examine and to then develop further working methods.
1) South wall, west section and test area on the west wall: base zone of the wall
The large lacunae of the loam plaster in the lower area of the base zone up to a height of about 50 cm were filled with loam putty to protect the adjoining broken edges of the painting. Subsequently a layer of coloured liquid loam, enriched with cellulose, was applied to the filling material.
2) West wall, south section
We continued the conservation work in the area above the base zone. The paint layer was cleaned, losses and cracks were filled.
3) South wall, east section
This testing area was chosen to focus on techniques of consolidating flaking paint layers and injecting substances into the hollow areas of the painting.
In some parts, there were large hollow areas beneath a rising and flaking paint layer. These hollow parts could no longer be fixed by flattening the surface, because larger pieces of the fine loam plaster had already fallen off. Subsequently, we filled the lacunae and cracks.
4) South wall above the door
Large parts of the painting here had been washed out by water coming down the surface and loam streaks had rendered the painting unrecognisable. About half of the painting was missing altogether and there were only fragments left of the remainder.
5) South wall, west section, base zone
Above the base zone, we continued the conservation work of the previous year. The paint layer was cleaned, the lacunae and cracks were filled.
6) Test section on outside wall of the temple (right-hand side above the door)
On the outside wall above the entrance and at the top right, there were some spots where the whitewash had been scratched open. The spots revealed a coloured sub-layer which led us to believe that the layers of whitewash concealed a painting. We sectioned off and laid open two fields of about 90x80 cm and 30x60 cm and uncovered a frieze of about 60 cm height and the depiction of the Bodhisattva Mañjuśrī.
Various attempts at removing the overpainting were made in order to then carry out a large-scale removal of the whitewash. We uncovered the painting mechanically.
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July/August 2003
by Martina Oeter, Steven Post and Barbara Sedlaczek
In 2003, we concentrated our work on sample areas of inpainting on the south section of the west wall (see Restoration). In addition, we cleaned and consolidated the east, north and south walls.
1) North wall
We cleaned this wall nearly completely from dust and lime splashes. The upper wall section in the right-hand corner was conserved. A section of painted plaster below the ceiling beam had become loose due to the weight pressure of the roof structure. This fragment was taken off the wall to remove the loose mortar. We then affixed the painted plaster section back to its original position (see main / north wall).
2) South wall, west section
We resumed our work of cleaning the surface, which was commenced in the fall of 2000 and continued in 2001. Apart from cleaning and reducing the loam streaks, we filled the lacunae with loam plaster.
3) East wall, base zone
Having cleaned the lower section of the east wall from dust, loam and whitewash, we filled the deeper cavities and lacunae with mortar and plastered the entire bottom section. While removing the whitewash (lime), we discovered parts of an underlying – probably original –painting at the base section. Due to the time constraints we did not lay open the entire painting at that time, but measured the finding and documented it in photos and protocols (base zone reconstruction).
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June/July 2004
by Yvonne Mohr and Steven Post
We concentrated the conservation work mainly on the south wall; cleaning the surfaces, fixing the detached parts of the painting and filling gaps and cracks in the plaster. As the damage in the upper part of the wall was quite extensive, the loose areas of the painting had to be fixed first.
1) South wall
This year the conservation work was continued on the upper zones of the wall. These areas were very deteriorated, so extensive protective measures had to be carried out, as outlined below:
- Lacunae were filled with loam putty. To improve its binding properties, cellulose was added to the liquid markalag.
- Flaking paint and fine loam layer were stabilised with liquid loam.
- Flaking paint layer was fixed with cellulose. To prevent moisture marks, the area in question was first sprayed with ethyl alcohol and then with the cellulose solution. Subsequently, these areas were cleaned and the plaster gaps were filled.
2) North wall
In addition to the conservation measures mentioned above, the filling of the large cracks was finalised. Liquid pigmented loam was applied on the smoothened surfaces. By this method the fillings blend into the surrounding colour scheme.
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June to August 2005
by Bernadette Mannuss and Alexandra Skedzuhn
1) South wall
We continued consolidating the plaster and the paint layer on the eastern side of the upper part of the wall. The paint layer was cleaned and the gaps and cracks were filled.
2) West wall
The missing area of the mandala in the lower part of the wall was inpainted. The lacuna in the valance motif was filled and the reduced paint layer was inpainted. Here, the thangka painter Konchok Norboo carried out some reconstruction samples.
3) North wall
We filled the gaps between the eastern area of the wall and the ceiling beams. We then carried out inpainting samples in the area of the filled cracks.
4) East wall
Here an emergency protection was necessary. The plaster and the paint layer were consolidated where new damage due to water seepage had occurred at the beginning of the year.
5) Southeast corner
The big crack between these two walls was reinforced and filled. A small fragment of painted plaster was removed from the current position (south wall) and reattached to its original location (east wall).
6) Clay sculptures
The surfaces were cleaned with a soft brush. The state of conservation and the technology was examined and documented in protocols.
Green Tara: Reattachment of small fragments.
7) Scientific examinations
Several pigments found in the paintings were identified by microscope and further samples were taken for examination in the laboratory at the Expert Centre for the preservation of historic monuments in Zurich.
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July to September 2006
by Gerold Ahrends, Yvonné Erdmann and Martina Oeter
The work concentrated on the two walls where some major conservation work still has to be executed, which are the south wall and the east wall. Additionally, the state of conservation and the technology of the wooden construction were examined. Then some conservation work was carried out on these elements, including their paint layer.
1) South wall (entrance area)
We continued filling the losses on the south wall. Cleaning and consolidation was carried out on the previously treated areas.
2) East wall
On the east wall more extensive cleaning and consolidation was necessary due to the damage that occurred in 2005. Small and larger cracks were filled as well as losses. We continued filling the large crack in the south-east corner.
3) Geese frieze
Thangka painter Konchok Norbu carried out a test area. For this he reconstructed three of the missing geese.
4) Wooden construction
The examination of the wooden construction included the materials and their condition. It followed the development of a treatment concept. An emergency consolidation was carried in the interior of the temple and the entrance area. This included:
- a preliminary consolidation of flaking paint, cleaning of the wooden support system and the lateral vertical beams. A protective coating was then applied on these beams.
- stabilisation of the bolt on the door, the cleaning and consolidation of the wooden surface and mounting the hanging system.
5) Scientific examinations
Some new samples have been taken from pigments, but above all from whitewash material and prime coating in different locations with the goal of finding answers for the questions which occurred after the investigations in 2005.
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July/ August 2007
by Philipp Schubert and Sven Trommer
1) West wall
The whole wall has been cleaned chemically and mechanically to remove the veil of whitewash on the northern part and the overall veil of loam and dust. Additionally all lacunae, plaster gaps and structural cracks have been closed with earthen putty and fine markalag mortar. The fixing/consolidation of the flaking paint layer and hollow areas of the fine plaster layer has nearly been finished.
2) East wall
The whole wall has been cleaned chemically and mechanically to remove the overall veil of loam and dust and whitewash/prime coating material. Additionally we were nearly able to finish the reduction of the loam streaks on the southerly mandala and the filling of plaster gaps and structural cracks with earthen putty and fine markalag mortar. Also the fixing/consolidation of flaking paint layer and hollow areas of the fine plaster layer could be finished to a percentage of about 80%.
3) South wall
Some emergency conservation measures like the fixation of small areas of flaking paint layer and small fillings have been executed.
4) Temple outside
Some emergency conservation measures like filling and consolidation of plaster gaps and cracks have been executed on the paintings. The loam stucco elements over the entrance door have been re-fixed in some parts. The old access hatch to the roof has been closed with flat stones and mortar. This measure has been done for better conservation of the already heavily weathered wooden pillar under the access hatch. Several structural cracks in the junction area between upper main roof and walls had to be closed with stone material, liquid mortar and loam putty. The porch roof was covered with flat stones in the area where water dropping from the upper main roof caused damage to the porch roof.
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