Lac Dye an important export item of Bengal from ancient times but ceased to be so from the mid-nineteenth century. Lac dye, commonly known as 'Bengal Lac' in foreign countries, was highly valued in England during the early phase of its industrial revolution. It was used in colouring textiles and other products. Lac constituted a valuable item in the export cargoes of the East India Companies of maritime Europe in the seventeenth and eighteenth centuries.
Lac dye was produced from several types of trees suitable for culturing lac worms. The lac cultivators used to culture lac worms in select twigs of particular trees. After a time the twigs were heavily infected by the sticky juice of worms and became red, pink or purple according to the nature of seed worms. The infected coloured twigs released all the colours. A small quantity of alum was added to the filtered solution. Then the solution was evaporated. The colour sediments were pasted into cakes of various sizes. Like the textile weavers, the lac cultivators were also engaged by foreigners to produce lac dye for them. But lac lost its world market with the invention of synthetic dyes in mid-nineteenth century. But its local use lasted till the early twentieth century. Lac was also produced in Burma and south India. But among foreign buyers Bengal Lac was in the greatest demand. Lac was exported both in twigs packed in gunny bags and in the cake form. Twig-Lac was obviously cheaper than cake-Lac. [Sirajul Islam]