Daguerreotype
Morse met the inventor of the daguerreotype, Louis-Jacques-Mande Daguerre, in Paris in January 1839 when Daguerre's invention was announced [2]. While the daguerreotype fascinated Morse, he was concerned about how the new invention would compete with his telegraph. However, Morse's viewing of the daguerreotype alleviated his fears when he saw how revolutionary its technology was. Morse wrote a letter to his brother Sidney describing Daguerre's invention, which Sidney then published in the New-York Observer on April 20, 1839. While this was not the first report of the daguerreotype to appear in America, it was the first in-person report to appear in the United States.
Daguerreotype
Usually, it was arranged so that sitters leaned their elbows on a support such as a posing table, the height of which could be adjusted, or else head rests were used that did not show in the picture, and this led to most daguerreotype portraits having stiff, lifeless poses. Some exceptions exist, with lively expressions full of character, as photographers saw the potential of the new medium, and would have used the tableau vivant technique. These are represented in museum collections and are the most sought after by private collectors today. In the case of young children, their mothers were sometimes hidden in the frame, to calm them and keep them still so as to prevent blurring.
The image in a daguerreotype is often described as being formed by the amalgam, or alloy, of mercury and silver because mercury vapor from a pool of heated mercury is used to develop the plate; but using the Becquerel process (using a red filter and extra exposure) daguerreotypes can be produced without mercury, and chemical analysis shows that there is no mercury in the final image with the Becquerel process. This brings into question the theory that the image is formed of amalgam with mercury development.