[Emlen Cresson, head-and-shoulders portrait, facing front]

The daguerreotype is a photographic process invented by the Parisian inventor and entrepreneur Louis Jacques Mandé Daguerre (1787-1851) who was the first person to publicly announce a successful method of capturing images. His invention was an immediate hit, and France was soon gripped by ‘daguerreotypomania’. Daguerre released his formula and anyone was free to use it without paying a license fee – except in Britain, where he had secured a patent. Daguerreotypes required a subject to remain still for several minutes to ensure that the image would not blur.

The Americana collection of Marian Sadtler Carson (1905-2004) spans the years 1656-1995 with the bulk of the material dating from 1700 to 1876. The collection includes more than 10,000 historical letters and manuscripts, broadsides, photographs, prints and drawings, books and pamphlets, maps, and printed ephemera from the colonial era through the 1876 centennial of the United States. It is believed to be the most extensive existing private collection of early Americana. The collection includes such important and diverse historical treasures as unpublished papers of Revolutionary War figures and the Continental Congress; letters of several American presidents, including Thomas Jefferson; a manuscript account of the departure of the first Pony Express rider from St. Joseph, Mo.; and what may be the earliest photograph of a human face. Many of the rare books and pamphlets in the collection pertain to the early Congresses of the United States, augmenting the Library's unparalleled collection of political pamphlets and imprints. The Carson Collection adds to the Library's holdings the first presidential campaign biography, John Beckley's Address to the people of the United States with an Epitome and vindication of the Public Life and Character of Thomas Jefferson, published in Philadelphia in 1800. The book was written to counter numerous attacks against Jefferson's character, which appeared in newspapers and pamphlets during the bitter election campaign. The Rare Book and Special Collections Division shares custodial responsibility for the collection with the Library's Geography and Map Division, Music Division, Prints and Photographs Division, and the Manuscript Division.

Robert Cornelius (1809-1893) was an American pioneer in the field of photography, best known for taking one of the earliest known photographic self-portraits. Born on 1 March 1809 in Philadelphia, Pennsylvania, he lived at a time when photography was in its infancy. In 1839, just a few months after Louis Daguerre introduced the daguerreotype, Cornelius set up a camera in the back of his father's gas lamp shop in Philadelphia. He removed the lens cap, walked into the frame and, after a long exposure lasting several minutes, replaced the lens cap. This self-portrait is one of the earliest surviving photographic portraits. The daguerreotype, named after Louis Daguerre, was the first commercially successful photographic process. It involved exposing a silver-coated copper plate to iodine vapour to create light-sensitive silver iodide on the plate. After exposure in the camera, the plate was developed with mercury vapour and fixed with a solution of common salt. Cornelius's self-portrait is significant not only for its historical importance as one of the earliest photographs, but also because it reflects the technical challenges of early photography, as evidenced by the long exposure time required. His pioneering work contributed to the development and popularisation of photography as an art and a science.