Abstract

The paper outlines the continuing trend towards the development of specialised metal complex dyestuffs and the importance of newly developed liquid versions, their production and advantages for the tanner over conventional powder versions. A brief review is included of the relative importance of the Colour Index, dyestuff availability and classification methods. Also, extended “trichromatic” dyeing systems are discussed as an intermediate stage, which have lead to the latest dyestuff developments, together with the implications of this for CCMP (Computer Colour Match Prediction). Factors affecting colour uniformity are mentioned and the numerous differences that have been observed between the modified metallised powder and liquid dye ranges are also highlighted. The paper concludes indicating the four major ‘classes’ of dyestuffs currently available in liquid form and considers how these can be exploited for the benefit of the leather manufacturer.