a b s t r a c t
5% omf dyeing of three 1:2 pre-metallised acid dyes displayed poor fastness to repeated washing at 60 C on 0.05 dtex ‘supermicrofibre’ artificial nylon suede. Although fastness was improved by an after treatment with the full backtan, considerable dye loss still occurred during repeated washing, which was attributed to the large surface area of the microfibre substrate. In contrast, the wash fastness of 4% omf dyeing of three vat dye, applied as both the alkali leuco and acid leuco variants, was substantially better than that of the acid dyes, despite the considerably higher colour strength of the vat dyeing. Although the rub fastness of the vat dyeing was higher than that of the acid dyeing, the level of rub fastness, especially wet, was only moderate. The colour and colour strength of the acid leuco dyeing
were generally different to those of the alkali leuco dyeings.