An Encyclopaedia of Indian Archaeology v1.c16.s14.13

v1.c16.s14.13

Chemical analysis of the black pigment used in the decoration of the ware revealed that the pigment was made up on iron oxide. It did not contain manganese dioxide or any carbonaceous matater (Hegde, 1975, pp. 187-90). When a sherd was heated in an open crucible at 600° C the black design slowly turned first yellow, then orange and finally red. The grey surfce attained a dull red colour. The scraped pigment was also found to be magnetic. It is therefore possible to identify the pigment as magnetite. This is interesting, revealing as it does that if magnetite was used as the pigment it would retain its black colour only if the ware had been baked in a reducing atmosphere. If on the other hand had red ochre, i.e. haematite, been used it would attain black colour and turn into magnetite only if the pot was baked under a reducing condition. In either case the experiment shows that the pottery was backed in a reducing atmosphere.