Abstract: The present invention is concerned with a dye system for application to a substrate, the dye system comprising: (a) at least one dye precursor; (b) an oxidizing agent; and (c) a catalyst, wherein the catalyst is a homogeneous catalyst or a heterogeneous catalyst. Preferably, the catalyst comprises at least one metal-containing compound. The invention also envisages a method for the coloration of a substrate, the method comprising treating the substrate with the dye system of the invention. In preferred embodiments of the invention, the substrate comprises human hair, natural or synthetic polymers, or textile fibers. In further preferred embodiments, the at least one dye precursor is an organic precursor, the at least one metal derivative for use as a catalyst comprises at least one inorganic metal compound or at least one metal complex comprising at least one organic ligand, and the oxidizing agent is hydrogen peroxide.

Abstract: The present invention relates to a composition for coloring keratin fibers and a method of using the same. The composition of the present invention contains at least one dye precursor, and one or more clathrate compounds that contain transition metal complexes.

Abstract: An easily employed, effective and predictable hair dye composition is obtained by combining aryl amines with aryl aldehydes along with an inorganic metal salt having a valence between +1 and +3. By employing this formulation, a permanent, long-lasting, non-fading hair coloring is achieved. In the preferred embodiment, the inorganic metal salt is selected from the group consisting of aluminum chloride, ferric chloride, lithium bromide, manganese chloride, copper chloride, and manganese nitrate. In carrying out the teaching of the present invention, the aryl amine and aryl aldehyde may be applied to the hair separately or in combination, along with the inorganic metal salt. In addition, this inorganic metal salt can be applied after the application and removal of the aryl amine and aryl aldehyde.

Abstract: A method is provided for tinting a hydrogel contact lens whereby the tinting effect is not appreciably affected by the underlying color of the iris of the wearer's eyes.

Abstract: An acidic, aqueous oxidant including ionized bromate, iodate and a soluble molybdenum-containing material.