The monastery at Buli is located at 3,300 meters, a few kilometers away from the village of Gaytsa, in the region of Bumthang. It is reachable from Thimphu after eight hours driving along winding roads. Dating back to the 14th century, it has been widely modified with the passage of time, thereby making it difficult to consider the paintings within, either for quality or technique of execution, contemporaneous to the foundation of the monastery.
The primary aim of the project, carried out by John Sanday Associates, was to train local people to restore the wall paintings in Buli’s monastery. The paintings, executed on three stories, were painted in different periods. Many dissimilar typologies of damage were evident. The target was to complete the restoration project carried out by Rodolfo Lujan Lunsford from 2002 to 2004. The project employed 14 locals who were trained in essential restoration techniques. These villagers worked even without the consultant’s presence, thanks to the supervision of specialists from the National Institute for Zorig Chusum.
The restoration of the wall paintings was almost complete on the east and west wall. Few areas still needed to be retouched. The eastern side of the west wall was nearly finished while the western side was only consolidated and a fragment of painting, previously detached, had to be set back to the wall. The work on the north wall was not started yet. The statues and their pedestals needed an intervention of restoration as well.
South wall: a portion of wall paintings on the west side had been detached in one of the previous missions and it had to be prepared before setting it back to the wall. The paint layer of the fragment had been protected with a layer of Japanese tissue paper and a layer of gauze glued with a dense solution of Paraloid B72. The back of the fragment had to be consolidated through several applications of Primal B60A (5% in water) after the application of a surfactant solution (water-spirit 1:1). Then the uneven surface was made plane with a plaster made out of local clay, strengthen with a PVA binder. After drying, the back was reinforced with two layers of cotton gauze glued with a mortar composed of an acrylic binder and sifted local clay. After that the fragment was turned with the paint layer upward. The facing of the painting, that is the layers of cotton gauze and tissue paper, was removed using cotton compresses soaked in organic chemicals. The area where the fragment had to be placed back was consolidated using an acrylic solution injected where needed. Then a plaster made of the same clay of the render was applied to the wall and the fragment was placed back in his original position before the plaster could set: care was given to merge perfectly all the outlines of the drawing. All the cracks were sealed with a plaster and injections of clay and PVA binder bonded safely the wall paintings fragment back to the wall. A propping was positioned so as to prevent the fragment from falling until the mortar and the binder dried completely.
The western side presented several remnants of Paraloid B72 in the form of drops/stains that had to be removed using Japanese tissue paper soaked in an organic chemical. The surface had not been cleaned properly and a revision of it was necessary prior any intervention of pictorial integration. The cleaning was carried out with a solution of EDTA disodium. The chemical was applied through brush and the grime and the soot were removed with an organic chemical after the surface was dry. A second application of both chemicals was done through Japanese tissue paper. A further washing with distilled water was required to remove any remains of the organic salt (EDTA disodium) from the surface of the wall paintings. Cracks and holes were plastered with whitish local clay mixed in a PVA binder.
The pictorial intervention was completed following two ways of intervention. Abrasions and areas that could be reconstructed were integrated using watercolors. Large areas of missing paint layer where the original sketch was still present were reconstructed following precise requests from the Home Minister and from the Dzongdag. The operation of reconstruction was organised in a way to be totally reversible. A base color prepared mixing natural pigments and a low solution of Arabic gum was applied on the surface of the missing parts. Subsequently the pictorial integration was completed with watercolors to match the original hues. The eastern side was not completed yet. Few cracks had to be plastered and the lower section had to be retouched.
North wall: since the paint layer was very thin it was decided not to consolidate the murals before the cleaning: this way would prevent any soot or grime from being fixed together with the pictorial layer. Moreover the render and the pictorial layer were dehydrated and it would have been easy for the soot to penetrate into the porous layers and be fixed with the operation of consolidation. The cleaning was divided in two operations. Deposits of grease and grime were taken away using dry Wishab sponges. The old and altered varnish was removed alternating the use of different chemicals. Japanese tissue paper was applied on the paint layer in order to avoid that the rolling or rubbing of cotton swabs could damage the paint layer. A solution of organic chemicals was alternated with a weak solution of EDTA disodium until all the aged varnish and any deposits of soot were completely removed. A further washing with distilled water was required to remove any remains of the organic salt from the surface of the wall paintings.
The areas of the wall paintings that were not sound enough were injected with an acrylic solution. When the gap was too deep finely sifted clay was added to the acrylic binder solution to be injected. All the injections were preceded by the dispersion of a surfactant solution through syringe. Cracks and lacunae were cleaned properly and sealed with a plaster made of clay and PVA binder. The retouching was carried out toning down light spots and balancing the hues of the paint layer using watercolors.
East and West wall: few cracks and holes had to be plastered and then retouched. Some areas needed to be revised because not finished properly.
The state of preservation of the vestibule was in very severe conditions. The wall paintings were coated with a thick aged brownish varnish. Cracks and losses of paint layer were generally present on the surface of the wall. Few portions of wall paintings had collapsed and a roughly made plaster was badly applied in recent times to fill the missing parts. The painted wood of the architrave was blackened and very few traces of painting could be seen.
The Wall Paintings: the decision of cleaning before consolidating was chosen in this situation as well. Deposits and dirt were dusted off using soft brushes and only few sections, where the paint layer was in risk of falling, were left untouched. In that case the paint layer was consolidated and subsequently dusted off and cleaned. In some cases of flaking paint layer, action was required prior to any intervention of cleaning: scales were softened with a surfactant solution through syringe, then an acrylic solution was injected on the back of the scales. The scales were set back in position with a slight pressure of spatulas wrapped in cotton/plastic. The excess of acrylic binder was removed with cotton swabs and water.
The cleaning was carried out in two times. At first, the grime was thinned down using cotton swabs and organic chemicals. The cleaning was completed the following day with the help of Japanese tissue paper: a solution of EDTA disodium and ammonium bicarbonate in water was alternated with an organic chemical until all the soot and the varnish were removed. A further washing with Japanese tissue paper and distilled water was required to remove any deposits of the salt from the paint layer. All cracks were sealed prior the consolidation intervention with a plaster made of local clays mixed with a PVA binder. The entire surface of the walls was checked and all the areas that weren’t sound enough were filled by injecting a mixture of sifted local clay and an acrylic binder solution. Every injection of mortar was preceded by the injection of a surfactant solution. When the gap was very thin the clay wasn’t employed and only the acrylic solution was injected.
Cracks and lacunae were plastered at the same level of the paint layer using a whitish clay mixed with a PVA binder. Deep and large gaps were plastered in two or three layers according to the depth of the gap. A first stone based plaster was applied so as to reinforce the structure and to level the missing section. After drying, a rough coating of sifted clay mixed with a PVA binder was put and left to set. At last a mixture of fine sifted whitish clay and PVA binder was applied up to the level of the pictorial layer. Where the gaps were not too deep the coating made out of rough clay was skipped. At the end the final plaster was smoothened using sand-paper.
The pictorial intervention was meant to tone down all the abrasions and the losses of colors that were disturbing the look of the wall paintings. In this case too, the large lost areas and the uncompleted sections on the lower side of the north wall were decided to be reintegrated in order to fulfil the decisions of the Home Ministry. Abrasions and losses of colors were toned down with watercolors. The plasters that had to be reconstructed were painted with a base color made of natural pigments and Arabic gum. The color was then matched with the original paint layer using watercolors.
The Architraves: the wooden architrave on the south wall presented traces of paintings in very bad conditions. The one on the north wall presented some decorations plus five carved lions inserted in it. The blackish layer of grime and varnish was thinned down with an organic chemical and the aged varnish was removed using Japanese tissue paper and cotton swabs soaked in a saturate solution of ammonium bicarbonate. A further washing with distilled water was required to remove any deposits of salt. The heavy abrasions and the missing parts were reconstructed using natural pigments mixed with a slight percentage of Arabic gum. The sections where the paintings were still present were retouched using watercolors.
The technique of execution of the paintings in the upper floors is different from the ground floor for the murals are painted with animal glue on a canvas subsequently glued on the wall (marouflage). The state of preservation of the wall paintings in the first and second floor was in quite good conditions. Paintings were in a good state of preservation and only few portions needed specific attention. Portions of the canvas on the southern side of the west and east wall were detached from the wall. Few cracks present on the surface of the walls caused the canvas to be torn apart. The wooden elements of the very finely carved architrave were in a good state as well.
The first operation carried out on the wall paintings was the cleaning. Since the kind of soot present on the wall paintings was mainly based on deposits from butter lamp smoke and grease, a dry cleaning carried out with dry Wishab sponges produced excellent results. The cracks in the walls were thoroughly cleaned and then plastered under the level of the paint layer: holes were left in order to allow a mortar to be injected later on. The injection of a mortar made of local clays and PVA binder was preceded by the injection of a surfactant solution. Then cracks were plastered at the same level of the paint layer with a whitish clay mixed with a PVA binder.
The back of the canvas detached from the surface of the wall paintings had to be thoroughly cleaned from the debris of mud: spatulas and sand paper were used to flatten the uneven surface. The wall had to be flattened as well and all the cracks and lacunae were plastered. When the mortar was dry the canvas was pasted back to the wall with a dense emulsion of PVA binder. Both the surfaces to be glued were wet with a surfactant solution. Cotton wrapped in a silk tissue was employed to flatten the canvas while being glued. Abrasions, cracks and lacunae were pictorially integrated using watercolors.
The project was successfully finished in winter 2005.