Use of lithium salts of anionic dyes to enhance their light-fastness

摘要

The use of lithium as a cation for an anionic dye to enhance the light-fastness of the dye. Also claimed are the lithium salts of certain anionic dyes as defined in the description; mixed lithium/sodium salts of an anionic dye wherein the molar ratio of lithium to sodium is from 1:4 to 99:1 and at least 20 mole % of the total counter ions in the dye are lithium cations; inks containing the dyes; a method of ink jet printing using the inks; a substrate printed with the inks; an ink jet printer cartridge containing the ink and a ink jet printer containing the ink jet printer cartridge.