Abstract
To investigate the dyeing characteristics of several natural dyes, cotton and wool fabrics dyed with palmatin, amur cork, gromwell, red wood, cochineal, and natural indigo. The yellow, red, and blue hue appeared on the cotton and wool fabrics dyed with palmatin and amur cork, red wood and cochineal, and natural indigo, respectively. These natural dyes could be used as the three primary colors to obtain a full range of colors. Bluish gray, pale red, and violet hue could be obtained on cotton by dyeing with gromwell extracted at different extraction temperatures and alum mordanting. The adsorption behavior of natural dyes varied. When dyeing was carried out without chochineal equilibrium was obtained in 20 minutes, while cochineal adsorbed on the fabrics gradually during 60 minutes. The rate and amount of adsorption of natural dyes on the fabrics may be affected by molecular weight and number of -OH groups in the dye structure, and respectively, and the amount of dye adsorbed and fixed on the fabrics was higher for wool than for cotton, and increased by alum mordanting.