Substantive dye is a dye used in a process in which dye molecules are attracted by physical forces at the molecular level to the textile. The amount of this attraction is known as "substantivity": the higher the substantivity the greater the attraction of the dye for the fiber. Substantive dyes work best on textiles with high contents of fibrous cellulose and are set in a slightly basic or neutral environment at high temperatures close to boiling point. Substantive dyes are set by hydrogen bonding.
