Dyestuff manufacturers are now focused on restricting colours in each class, close to the three primary colours, with similar dyeing characteristics and two objectives. Control mechanisms and automation are discussed, followed by the role of specialty chemicals (four functions noted). Alternate processes are listed and the most common classes of colours on different substrates listed. Vats are discussed in considerable technical detail with dyeing principles and methods included. Dyeing of vats takes several forms with four fabric dyeing methods listed. Problems encountered can be process related or machine related and these are explained. Substrate preparation is described. Choice of colours and their impact on dyeing/leveling/oxidation covers grouping of vat colours - IK, IW, IN special. The differences in treatment of these groups are discussed in relation to temperature, alkalinity and exhaustion characteristics. Specifics required for certain colours are then explored.