3.2.3. Syntan + cation after treatment
Table 4 and Fig. 8 show that the use of this after treatment increased the lightness and reduced the colour strength, respectively, of the dyeings prior towash testing. The observation that the extents of the reduction in fk and increase in L* were greater for the syntan + cation after treatment than the syntan after treatment can be attributed to more dye having been desorbed from the dyed substrate during the two hot, aqueous stages of the syntan + cation process. Table 4 shows that, for both dyes, after treatment with the syntan + cation process had little effect on the chroma and hue of the dyeings, as was observed for the syntan after treatment, which
can be attributed to the moderately deep and relatively dull shades used. In the context of the fastness of the dyeings, Fig. 8 shows that the extent of the reduction in fk of the syntan + cation treated dyeings was greater than that achieved for the dyeings which had been after treated with the syntan. Thus, the fk data (Fig. 8) shows that after treatment with the syntan/cation process improved the fastness of both dyes to repeated washing. This was supported by the staining results obtained (Table 3) which revealed that the syntan + cation after treated dyeings displayed slightly superior fastness after five washes than their non-after treated counterparts. Furthermore, in the context of the extent to which the depth of shade of the dyeings was reduced during repeated wash fastness testing, the % colour loss values (Fig. 9) show that the syntan + cation after treatment was more effective than the syntan
after treatment for both dyes.