Table 6.3 details the recipe for the two reduction baths evaluated in this study. The chemical ratios were based on equivalent requirements for exhaust dyeing. Dextrose served as a stabilising agent. Bath A introduced TUD as the reducing agent while in Bath B caustic soda was also replaced by sodium carbonate. The dried fabric, after padding with indigo, was padded with either Bath A or Bath B using 3 dip–3 nip technique with 80% wet pick-up. This was immediately followed by steaming at 100○C and 100% RH. Steaming durations of 30, 60 and 90 seconds were evaluated when padding in Bath A. Steaming duration was based on the industrial practices for padding of vat dyes, which usually involve a steaming duration of 30–60 seconds [11, 50]. The shortest steaming duration beyond which no significant increase in depth of shade became evident was selected as the ideal steaming time. This principle was the basis for increasing the steaming time evaluated to 2, 4 and 6 minutes when reduction was carried out using Bath B.
