Colourimetric analysis and antimicrobial study of natural dyes and dyed silk

Colourimetric and antimicrobial activities of natural colourants and dyed silk have been studied. The colour strength (K/S) values were increased with increase in dye absorbance. The absorption of dyes on silk yarns was obtained from 10.56 to 39.48% at 5% concentration of dye from different plant extracts. The colourimetric parameters L∗, a∗, b∗, C, and H were measured for depth of the colour. The dyed silk with natural colourants displayed excellent antimicrobial activity (reduction rate: 25–65%) against the bacteria Escherichia coli and (reduction rate: 3–68%) against the fungal strain Aspergillus niger. The dyed silk exhibited good and durable fastness properties.