Daguerreotypes. First developed by Louis Daguerre in France, daguerreotype technology came to New York in 1839, in the wake of the economic Panic of 1837. In the spring of 1840 Alexander Wolcott, an inventor and dentist, teamed with the chemist John Johnson to open the world's first commercial photographic portrait studio in New York City, but it was Robert Cornelius of Philadelphia who proved that daguerreotype portraiture was commercially viable. Cornelius experimented with the new technology and managed to achieve successful and reliable exposure in under a minute. At the same time Cornelius actively encouraged important Philadelphians to have their portraits made at his studio. The perceived moral benefits of viewing portraits of the great and the good would help to legitimatize photography in America as an art form.

Brady. Mathew Brady, best known for his Civil War photography, established his first gallery in New York in 1844, and...