Of all the types of dye available for dyeing cotton direct dyes are the simplest to use. They can easily be applied to cotton or other cellulosic fibres without the need of pre-treatment or mordant, by heating the dye solution and adding common salt or Glauber's salt to increase dye take-up. Poor to moderate fastness to wet treatments. Light fastness varies from poor to very good according to group, for example: Moderate light fastness: Chlorazol (ICI), Diphenyl (Ciba-Geigy), Benzo (Bayer) High light fastness: Durazol (ICI), Chlorantine fast (Ciba-Geigy), Sirius supra (Bayer)

An anionic dye used for dyeing cellulosics. Requires the presence of electrolytes in the dyebath.