Two step hair coloring compositions delivering deeper, long-lasting color

A method of coloring hair comprising the following sequential steps:

• a) contacting the hair with an aqueous dye precursor mixture comprising:
• i) an oxidative hair dye precursor,
• ii) a fatty component or components comprising
• a) a sparingly soluble fatty amine having a water solubility less than 1 gm per liter selected from the group consisting of stearamidopropyl dimethylamine, dicetyl dimethylammonium chloride, PEG 3 cocamine, dihydroxyethyl soyamine dioleate and mixtures thereof,
• b) non-amine fatty ingredients selected from the group consisting of C12 to C22 fatty alcohol and their alkoxylates, nonionic surfactants, volatile or non-volatile silicones, hydrocarbon oils, ester oils and mixtures thereof,
• iii) a water miscible organic solvent,
• wherein the total weight of the sparingly soluble fatty amine plus the non-amine fatty ingredient in the precursor mixture, ΣFC, and the weight of the organic solvents in the precursor mixture, ΣOS, satisfies the inequality, ΣFC<0.037(ΣOS)2−3.35(ΣOS)+63,
• wherein the dye precursor mixture does not contain an oxidizing agent,
• b) contacting the hair with a developer mixture capable of inducing oxidation of the oxidative dye precursor that is in contact with the hair to form colored species, and
• wherein the aqueous dye precursor mixture remains in contact with the hair for a time period of from about 0.5 to 60 minutes before the hair is contacted with the developer and wherein the oxidative hair dye precursor remains substantially inactive during this time period.