Silk and wool yarn dyed using nine, commercial direct and acid dyes. For examining the effect of different aftertreatments, the dyed samples were aftertreated using four different commercial systems, namely a tannic acid, a tannic acid/enzyme, the traditional fullbacktan and the newly developed fullbacktan processes. When all dyeings were subjected to ISO105C06 wash test, it was found that all four aftertreatments improved wet or wash fastness. Comparison the results from repeated wash test, using dye fastness factor ( DFF ) were confirmed by colour strength factor ( f k ) and spectrophotometeric data’s. For determination the optimum application conditions for the tannic acid and the tannic acid/enzyme system, the effects of pH and temperature have been investigated. The effect of the tannic acid system in improving wash fastness was increased by reducing applied pH from 6 to 3, while in the case of the tannic acid/enzyme system, DFF decreased initially and then increased. It was found that optimum conditions for the tannic acid/enzyme process were 70 °C at pH 6. Also it was found that optimum conditions for the tannic acid aftertreatment were 70 °C at pH 3. However, aftertreatment of the dyeing using the traditional fullbacktan system showed the greatest wash fastness improvement toward repeated wash test. Aftertreatment by the tannic acid system showed the lowest DFF toward repeated wash test. While determining the light fastness of dyeings using the ISO105B02 method, it was found that four aftertreatments system had no influence or a little effect on light fastness of samples.
