Legend has it that Raja Serfoji II (1797-1832), the Maratha ruler of Thanjavur (or Tanjore), asked artisans in his court to create an object that would reflect the glory of his kingdom.This resulted in the creation of the Tanjore metal plate. Three metals — silver, brass, and copper — are encrusted on to each other to create this unusual object. The effect of silver in high relief on the reddish copper ground is unusual and striking. Artisans belonging to the Vishwakarma community follow this hereditary profession in Thanjavur (Tamil Nadu).
This unusual encrusting of metal on metal has as its base a plate of brass which is prepared by a heavy-metal worker; the relief on copper is prepared by a jeweller and the encrusting is done by a stone-setter with silver. Some artisans, however, work on all the three processes themselves. The tools required to practise this craft include hammers, pincers, mould, punches and chisels, grinding stones, and a forge. Most of the tools are made by the artisans themselves.
In the first stage the base is cut to the size of plate which is planned. The average thickness of the brass plate may vary from 10-24 gauge(s); this is cut to the required circular size and polished on its front side. It is fixed firmly to an asphalt bed with a wooden base. The bed is then heated with a blow pipe and levelled and the basic design die is prepared. The silver and copper sheets are then cut to the size required and heated slightly to make them malleable before they are impressed on to the die. The impression thus achieved on the metal has to be finished by etching and refining the embossing with the aid of chisels and punches.
The next stage is that of encrusting and superimposing the metal sheet(s), which is then followed by the final polishing. To encrust the metals the hollow depressions at the back of the relief sheet are filled in with locally prepared wax made of brick powder, gingili oil, and frankincense. The relief sheet is then placed on the base plate and it is riveted on by punching along the grooves.
Traditional Tanjore art plates have, on the central circular metallic disc, a representation of deities like Nataraja, Saraswati, Ashta Lakshmi, and Ganapaty. The designs around the central main motif can be from the pantheon of Hindu deities or floral designs. Intricate designs detail the plate and add to the ornamentation.The planning of the design involves the selection and putting together of the designs and motifs from a stock of standard patterns and designs available in design plates or moulds. A new design requires a new plate or mould to be prepared. Besides plates, other products — including includes bowls, boxes, napkin ranges, key chains, and paper weights — are made using the same technique. Logos and emblems of corporate houses and organisations have also been embossed.