3.2.2. Syntan after treatment
Table 4 shows that for both dyes used, syntan after treatment had little effect on the hue and chroma of the dyeings, which may be attributed to the moderately deep and relatively dull shades employed in this work. The colorimetric data (Table 4) also show that after treatment increased the lightness of the dyeings, this being accompanied by a corresponding decrease in colour strength (Fig. 8); these findings can be attributed to dye having been desorbed from the dyed silk during the syntan after treatment process. The fk values in Fig. 6 show that for almost every wash test, the extent of the reduction in the colour strength of the syntanned dyeings was lower than that obtained for the corresponding non after treated dyeings. Hence, after treatment with the syntan improved the fastness of the three dyeings to repeated washing, this being confirmed by the lower extent of staining of adjacent materials recorded for the syntanned dyeings after five washes (Table 3). In terms of the reduction in depth of shade that occurred as a result of repeated wash fastness testing, the % colour loss values displayed in Fig. 9 show that syntan after treatment was very effective in reducing the extent of colour loss for both dyes used.