Methods and compositions for improving the quality and durability of color in artificially colored hair

The present disclosure relates to methods for improving the quality and durability of color in artificially colored hair. The methods employ alkaline earth metal salts that act as a mordant (a fixing agent) with the dye and hydroxy-polycarboxylic acids, which act as chelators. The artificially colored hair is treated with a post-color treatment composition comprising one or more alkaline earth metal salts and one or more hydroxy-polycarboxylic acids. Also, the one or more alkaline earth metal salts may be incorporated into a coloring composition for coloring the hair (in-color treatment composition) and a subsequent post-color treatment composition comprising one or more hydroxy-polycarboxylic acids can be applied to the hair.