Eco-Dyeing of Wool Using Aqueous Extract of the Roots of Indian Madder ( Rubia cordifolia) as Natural Dye

The aqueous extract obtained from the powdered roots of Indian madder (Rubia cordifolia) was used for dyeing of woolen yarns. The effect of pH, dye concentration, and mordants on the colorimetric and fastness properties has been studied. Brilliant shades of bright red to scarlet were obtained with significant variation in hue and tone of shades depending on mordants and dye concentrations used. The color coordinates of the dyed samples were found to be in the red-yellow quadrant of the CIELab color space. It was found in all cases that mordanting with alum as well as ferrous sulfate has caused decrease in lightness (L*) values and increase in K/S values. All the dyed samples exhibited commercially acceptable fastness to light, washing, and rubbing. Scanning Electron Microscopy (SEM) morphological studies have also been performed on different woolen yarns.