Table 4 shows thatthe wash fastness ratings of both non-mordanted and mordanteddyed samples were very poor to poor (1–2), except for ferrous sul-fate mordant, whose rating was fair to good (3–4). The low grayscale rating is caused by the original color of the dyed fabric visuallybecoming more reddish after the washing test, as indicated by thepositive values of a*, except for copper sulfate mordant (Table 5).This drastic color change may be attributed to (a) the ionization ofthe hydroxyl groups in the dye molecules under the alkaline con-dition of the standard detergent solution