Natural dyes have been synonymous with the traditional Indian textiles like Kalamkari, Madhubani painted textiles from Rajastan, Patolas and Kashmiri shawls. Bangladesh, then known as East Bengal became famous for its Muslin Jamdanis and Nakshi Kanthas that were coloured with natural dyes. Natural dyes have been used in wooden toys, mats, baskets, ivory and decorative paintings along with prolific use of dyeing cotton, wool, silk and rayon. There are evidences of the use of natural dyes for decorating the body by the primitive tribes. Today, henna leaves are used to paint beautiful patterns on the hands and the feet. In this article we have reviewed shade variations treated with different leveling agents and mordants.
Selected materials and methods given below:
Alkaline method was suitable for extraction of dye from eucalyptus bark. The optimum time for extraction of dye liquor from the bark was found to be 60 minutes. A dye material concentration of 4 per cent (2g. /g. of fabric) was selected. The optimum time for dyeing was 45 minutes for both the dyes. Cotton fabric was pre-treated with 20 per cent myrobalan concentration to increase the tannin deposition which in-turn increased the depth of the shade obtained. Five per cent solutions of leveling agents were selected such as soda ash, glaubers salt, common salt, di-ammonium hydrogen phosphate and magnesium chloride hexa hydrate. Based on absorption values, depth of the shade and appearance, three concentrations per each mordant was selected. In case of alum 5, 10 and 10 per cent and 1, 2 and 3 per cent concentrations of stannous chloride and ferrous sulphate mordants for cotton were selected for pre mordanting cotton fabric.
Treatment with leveling agents:
This treatment was given to the fabric while dyeing for 30 minutes. Five eco-friendly leveling agents were selected for treatment. This treatment was given by 5 per cent solution of each of the leveling agents. The solution was then divided into three parts. While dyeing, all the three parts were added to the dye solution at 10 minutes gap. After all the three parts of the leveling agents were added, the fabric was removed, rinsed in soap solution and dried. These leveling agents were selected based on commonality and effectiveness on dyes used for cotton dyeing.
Shade variations in Eucalyptus bark dyed cotton due to simultaneous treatment with leveling agents:
Eucalyptus bark dye on cotton showed different shades by varying the mordants and simultaneous treatment with 5 percent leveling agents. All dyed samples showed difference either in depth or in hue when treated with varying eco-friendly leveling agents. All dyed samples showed difference either in depth or hue when treated with varying eco-friendly leveling agents.
Soda ash treatment was tried on cotton mordanted with alum, stannous chloride and ferrous sulphate and dyed in eucalyptus bark. Light to dark shades with added brightness was observed in alum mordanted samples with slight pinkish shade. Unique level dyeing was observed in all alum mordanted samples. But light dull cream shades were produced in stannous chloride mordanted samples after the treatment with soda ash. Ferrous sulphate mordanted samples produced good leveled grayish creams.