Method of manufacturing a water-insoluble dye layer on a substrate and substrate comprising a dye layer of a cationic dye or an anionic dye ion exchanged with an opposite ion

摘要

A method of manufacturing a homogeneous, water-insoluble dye layer on a substrate is provided in which a solution of a cationic or anionic dye in an organic solvent is provided on the substrate, the solvent is removed and the resulting dye layer is treated with an aqueous solution of a salt in which the cation of the anionic dye is exchanged for the cation of the salt or is treated with a salt or acid in which the anion of the cationic dye is exchanged for the anion of the salt or acid. The invention also provides a substrate provided with water insoluble homogeneous dye layer.