A method for dyeing hair includes applying a polyvinyl amine copolymer solution to the hair； and applying a hair dye composition to the hair. A hair dye composition includes an aqueous base fluid； a polyvinyl amine copolymer； and an anionic or cationic hair dye. A method of making a hair dye composition includes mixing a polyvinyl amine copolymer and an anionic or cationic hair dye into an aqueous base fluid.
