Patent ID: 6428946
Filing Date: 2002-08-06
Classification: G03C

Abstract:
A method of making a multi-part color developing kit comprising:A) making a first solution to have a pH of from about 7 to about 12.5 by mixing in water, a first chemical base, a color developing agent present as a sulfate salt, an antioxidant for said color developing agent, alkali metal ions in at least stoichiometric proportion to said sulfate salt, and a water-miscible or water-soluble hydroxy-containing, straight-chain organic solvent for said color developing agent in free base form, said organic solvent having a molecular weight of from about 50 to about 200, to form an alkali metal sulfate in said first part, B) removing the alkali metal sulfate from said first solution, and C) adding to said first solution a triazinylstilbene optical brightening agent, and D) making an aqueous second solution to have a pH of from about 7 to about 12.5 of a buffering agent, a second chemical base, and at least one phosphonic acid metal ion sequestering agent.