Abstract


Natural dyes comprises of those colourants (dyes and pigments) that are obtained from animal or vegetable matter without chemical processing. They are mainly mordant dyes although some vat, solvent, pigment, and acid types are known.


Natural dyes find use in the colouration of textiles, foods, drugs, and cosmetics. Small quantities of dyes are also used in colouration of paper, leather, shoe polish, wood, cane, candles, etc. In the earlier days, dyes were derived only from natural sources. But natural dyes suffer from certain inherent disadvantages of standardized application and the standardization of the dye itself as dyes collected from similar plants or natural sources are influenced and subjected to the vagaries of climate, soil, cultivation methods etc. Hence for the natural dyes to be truly commercialsed and to take a competitive place with respect to the synthetic dyes, the standardization methods play a very significant and vital role. In this paper we shall indicate some conventional and often used methods of application, the identification methods and also standardization process of the natural dyes.


Natural dyes comprises of those colourants (dyes and pigments) that are obtained from animal or vegetable matter without chemical processing. They are mainly mordant dyes although some vat, solvent, pigment, and acid types are known.


Natural dyes find use in the colouration of textiles, foods, drugs, and cosmetics. Small quantities of dyes are also used in colouration of paper, leather, shoe polish, wood, cane, candles, etc. In the earlier days, dyes were derived only from natural sources. Some processing was required but essentially the dye itself was obtained from a plant, mineral or animal. After the accidental synthesis of mauveine by William Henry Perkin in 1856 and its subsequent commercialization, heralding the advent of coal tar dyes (now synthetic dyes), the use of natural dyes receded. A wide range of synthetic dyestuff was thrust upon the industry and it was readily accepted for its distinct advantage over natural dyes with respect to application, colour range and availability.


Status of Natural Dyes in India: India has a very rich tradition of using natural dyes. The art and craft of producing natural dyed textile has been practiced since ages in many villages by traditional expert crafts-persons in the country. Natural dyes, when used by themselves have many limitations of fastness and brilliancy of shade. However, when used along with metallic mordants they produce bright and fast colours. The use of metallic mordants is not always eco-friendly, but the pollution problems created by metallic mordants are of very low order and can be easily overcome. Therefore, instead of using unsustainable technology for producing colours one can use Mild Chemistry to achieve almost similar results.


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Dr. Ruma Chakrabarti is Associate Professor at Kumarguru College of Technology and A. Vignesh is Technical Compliance Manager in Hohenstein India Pvt. Ltd.