Archaeological chemistry survey – India

Survey of methods used by the Chemical department of India’s department of Archaeology to ameliorate natural decay of monuments and preserve mural paintings as described in various reviews of Indian Archaeology (Source: Department of Archaeology, India).

1953-1954 Indian Archaeology report

  • Noted that Ajanta cave painting’s stucco edges had been treated with unbleached shellac-varnish in the previous 30 years (1923-1953). In that year 1953/54 edges filled instead with bleached shellac varnish solution in rectified spirit. Method changed in following year’s report.

1954-1955 Indian Archaeology report

Monument treatment and methods

  • fungicidal applications to check algal growth that include use of very dilute solution of zinc silicoflouride (e.g. on sculpture at Khajuraho);
  • reduce flaking of wall paintings;
  • photograph, sketch and draw existing wall paintings;
  • 14 Ajanta caves have wall paintings (1,2,6,7,9,10,11,16,17,19,20,21,22,26). Removal of superficial accretions (dust/dirt/cobwebs/insect) by gentle brushing and application of organic solvents. Soot/lichen/moss cleared with rectified spirits and few drops ammonia.
  • Prior treatments of shellac-varnish coatings removed with rectified spirits.
  • 2 caves of 32 in Ellora have paintings (16 and 32).
  • 5 caves of 9 at Aurangabad have paintings (3,4,6,7,8). Edges of paint film and painted stucco secured with thick vinyl acetate solution and tinted plaster of paris. Painted surface given preservative coating of vinyl acetate.
  • Ink stains made by visitors on paintings removed by application of weak aqueous solution of oxalic acid.
  • Chemical analysis used to reveal earlier paintings that had been covered up. Example at Brihadisvara temple in Tanjore where some 16th century Nayaka paintings removed to reveal the earlier Chola period below.

Antiquities and museum exhibit treatments

  • treatment of silk, cotton, and, paper paintings (method not described).
  • steps to preserve wall paintings where pigments loose and flaking and where the ground and plaster brittle and crumbling. Treatment comprised fixing larger loose fragments with plaster of paris on back after removal of dust from painted side. Small piece on painted side reset with fixative. Complete fragment then made into rectangular block i/2 inch thick with plaster of paris and painted side when dry coated with preservative.


  • methods trialled in lab to deal with darkened brittle shellac-varnish that had been applied in earlier years to paintings such as Ajanta wall murals. Goal being to remove varnish without disturbing original pigments and affecting colour values. Mixture of water, rectified spirit, and, organic detergents and mixtures of organic solvents such as rectified spirit or absolute alcohol helped to remove smoke and tarry matter (from ceilings) in addition to yellow shellac-varnish.
  • Experiments found that bleached shellac solution that had been used to preserve paintings (1953-1954 report) became yellow with age. And films of that solution susceptible to cracking and darkening due to exposure to heat and light.
  • Examinations of glass bangles from Hastinapura revealed that in Painted Grey Ware pottery period manufacture and working of glass had been fully understood.   


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