Daguerreotype
It is said that Daguerre has found the means to collect, on a plate prepared by him, the image produced by the camera obscura, in such a way that a portrait, a landscape, or any view, projected upon this plate by the ordinary camera obscura, leaves an imprint in light and shade there, and thus presents the most perfect of all drawings ... a preparation put over this image preserves it for an indefinite time ... the physical sciences have perhaps never presented a marvel comparable to this one.
A further clue to fixing the date of invention of the process is that when the Paris correspondent of the London periodical "The Athenaeum" reported the public announcement of the daguerreotype in 1839, he mentioned that the daguerreotypes now being produced were of considerably better quality than the ones he had seen "four years earlier".
Ezra Greenleaf Weld
Of the six daguerreotypes of Douglass that have survived, only one besides Greenleaf's image has had its daguerreotypist identified. Greenleaf's image is unique because it is a group shot at an outdoor meeting rather than a studio portrait. Daguerreotypes were seldom attempted under these circumstances because the long exposure time required made it difficult to get a satisfactory result. Weld's is the only daguerreotype of Douglass whose date is known with certainty. This daguerreotype is also unique in the paradoxical sense that it is the only one known to have been copied. Two original half-plates exist: One is held by the Madison County Historical Society in Oneida, New York, the other is in a private collection and currently on display at the Smithsonian Institution in Washington, D.C. The copy (shown above) is in the J. Paul Getty Museum, Los Angeles, California.