Provided is a method for forming chrome-free retanned leather, including: (a) contacting wet white (chrome-free tanned hide) with a retanning mixture comprising from 2%to 15%, by solids weight, based on the wet weight of the wet white, of an amphoteric polymer composition comprising amine functional units and acid functional units; and (b) applying a polymeric overcoat containing an acrylic copolymer with one or more metal transition elements, with a thickness of no greater than 100 microns, to the retanned wet white. Also provided is a chrome-free retanned leather formed by the method.