It was observed from different experiments that the postmordanting
method imparted better shades on cotton yarn than
the pre-mordanting method. A variety of colour hues was obtained with respect to the nature of mordants such as alum, CuSO4, SnCl2
and FeSO4 by adopting post-mordanting technique. The fastness
rating for washing was evaluated by comparing with Grey Scale
standard (ISO-105). It was observed from the washing fastness data
that the cotton yarn dyed in presence of metal salts as mordant
furnished different colour hues with fairly good to very good wash
fastness ratings ranging from 3 to 4 (Table 3). The brightness of the
shades on cotton yarn might be due to the better absorption of dye
and easy formation of metal complexes with the yarn. The leftover
mordant solution re-used continuously in subsequent mordanting
of fresh cotton yarns after maintaining the desired concentration