 Talbot is sometimes erroneously credited with introducing the principle of latent image development.The bitumen process used in private experiments by Nicéphore Niépce during the 1820s involved the chemical development of a latent image, as did the widely used daguerreotype process introduced to the public by Niépce's partner and successor Louis Daguerre in 1839.Talbot was, however, the first to apply it to a paper-based process and to a negative-positive process, thereby pioneering the various developed-out negative-positive processes which have dominated non-electronic photography up to the present.