The lac dye is bright red. It is derived from insects like cochineal, kermes and lac, also called Kerria lacca. It takes about three lakh insects to yield one kilogramme of dye.

These scale insects thrive on a variety of trees and bushes such as kusum (Schleichera oleosa), palash (Butea monosperma), ber (Ziziphus mauritiana). They can be destructive to trees, stunting or killing twigs and branches by draining the sap. They exude a secretion from their bodies, which forms a hard resinous layer. This is the lac resin or sticklac.

Before they damage the trees, the insect bodies along with its secretions are scraped off from the twigs and branches and manufactured into shellac that yields the lac dye. Natural colouring substances, derived from shellac, like carminic acid, kermesic acid and laccaic acid are popularly known as the lac dye.

India is endowed with a wealth of natural flora and fauna, which provide the basic resource for a rainbow of natural dyes (see table: Plant sources of natural dye). Widely distributed in the rural belt, these are in close proximity to traditional dyers and handloom weavers. "Organic dyeing not only helps preserve the traditional art of weaving and design but also provides employment and yields economic and ecological benefit,' says Kapoor. "Natural dyeing can be a powerful tool to regenerate flora and maintain local biodiversity,' he adds.

In some rural areas of Kachcha, Gujarat and Kalahasti, Andhra Pradesh, natural dyer and weaver communities still work together. This also yields benefit for the farmer. Some of the natural dyes like indigo are leguminous and play a role in the crop rotation of rice. "For instance, when synthetic indigo became popular and natural indigo seeds were no longer collected, rice fields lost out on a valuable input by which nitrogen from the atmosphere was fixed in the soil,' says M I H Farooqi, former head of phytochemistry at nbri, Lucknow .

"Even flowers, fruits, seeds, leaves, stem, bark, wood and root of numerous dye plants contain colours and are renewable sources. Similarly, the waste after extraction can be utilised as fertiliser,' says Kapoor.

The most important plant-based vegetable dyes in India are indigo (Indigofera tinctoria) and madder (Rubia Cordifolia). Even parts of pomegranate (Punica granatum), lac (Kerria lacca), mehandi (Lawsonia inermis), ratanjot (Arnebia nobilis) and turmeric (see box: God's yellow) are used for extracting colours.

However, of the many plant species in India that yield dyes, few have been exhaustively studied for strategic cultivation.