Moses Billings
With the development of the daguerreotype in the 1840s, the role of the portrait painter declined in general, because it was now much easier and much cheaper to have one's likeness presented in a visual format. While many portrait painters lost business in competition with the daguerreotype, Billings instead began to produce daguerreotype prints himself. It is not known exactly which prints were made by Moses Billings, as daguerreotypes were usually signed, when signed at all, along the side of the plate. Due to the traditional storing methods of daguerreotype plates, even this signature usually quickly became illegible. However, it has been generally noted, or at least hypothesized, that his daguerreotype prints showed a level of talent and artistry above that of amateur daguerreotypists. Though it is not known exactly which prints were his, it is known that he had largely abandoned the process by the 1850s. Even after he stopped making daguerreotypes, he did continue to paint people's portraits on canvas.
Daguerreotype
After Niépce's death in 1833, his son, Isidore, inherited rights in the contract and a new version was drawn up between Daguerre and Isidore. Isidore signed the document admitting that the old process had been improved to the limits that were possible and that a new process that would bear Daguerre's name alone was sixty to eighty times as rapid as the old asphalt (bitumen) one his father had invented. This was the daguerreotype process that used iodized silvered plates and was developed with mercury fumes.