Characteristics of Color Produced by Awa Natural Indigo and Synthetic Indigo

Color of cloth dyed with Awa natural indigo is quantitatively compared with color of the cloth dyed with synthetic indigo. Results showed that: 1) color produced by Awa natural indigo is bluer and brighter than color produced by synthetic indigo; 2) a single Gaussian function fits the profile of the running of color produced by Awa natural indigo and the running of color produced by synthetic indigo prepared with sodium hydrosulfite approximates a linear sum of two Gaussian functions; 3) before and after washing, color is quantitatively more uneven when produced by Awa natural indigo than when produced by synthetic indigo; 4) the diffusion coefficient of Awa natural indigo is lower than that of synthetic indigo; 5) color superiority of Awa natural indigo relates to smaller diffusion coefficient, slower reduction, poorer penetration, and higher dye aggregation.