buli lhakhang

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.

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 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.