Much of the credit or blame for developing mass-marketable forms of photographs in the United States should go to the Langenheim brothers, Frederick and William, of Philadelphia. Between 1845 and 1860 they introduced a string of innovations that resulted in landscape stereographs becoming the first variety of photographs to achieve mass distribution. The story of that accomplishment constitutes an important chapter in the development of a mass market in the U. S. for pictures in the broadest sense.

[source: Rochester City Newspaper events calendar, 2019-Oct-14]