Effect of Dual Mordanting, Selective Dye Concentrations and Dye Compatibility for Minimizing Variation in Natural Dyeing of Jute Fabrics for Compound Shade Matching

Effect of dual pre-mordanting, dye concentration and test of dye compatibility of binary mixture of natural dyes applied on jute fabric have been studied for minimizing variation in natural dyeing of jute fabrics for preparing matched compound shades. The concentrations of individual mordants applied sequentially were optimized for getting best colour strength of dyed fabrics and a combination of 10% harda + 10% potash alum was found the best. The plots of dye concentration versus K/S values of dyed fabrics have been linearized and a linearized database for match prediction was prepared to get precision matching. Relative compatibility ratings of binary mixtures of selected natural dyes were calculated and three combinations—tesu + pomegranate, tesu + babul bark and tesu + marigold—have been found to be the best. Standardized colour database has been prepared by varying dye concentration for all selected natural dyes. Experimental results show that CV% of K/S values, colour difference index (CDI) values and colour matching index (CMI) values are also within permissible limit (below 5%) for least metameric and least cost colour matching generated with this colour data base of these natural dyes, this experimental information is practically very useful for dyers of both small and large scale textile dye-houses for its use in computer-aided colour match prediction to obtain desired matched compound shades. Post-treatment with (1) 2% alkaline cetyl trimethyl ammonium bromide (CTAB) and cetrimide improves wash fastness nearly 1 grade and (2) with 1% benzotriazole UV-absorber improves light fastness of these natural dyed jute decorative products nearly 1/2–1 grades.