Mark Ruwedel, artist and professor of photography, California State University, Long Beach; and Sarah Greenough, senior curator and head, department of photographs, National Gallery of Art. In 1990 the National Gallery of Art launched an initiative to acquire the finest examples of the art of photography and to mount photography exhibitions of the highest quality, accompanied by scholarly publications and programs. In the years since, the Gallery's collection of photographs has grown to nearly 15,000 works encompassing the history of the medium from its beginnings in 1839 to the present, featuring in-depth holdings of work by many of the masters of the art form. Commemorating the 25th anniversary of this initiative, the Gallery presents the exhibition The Memory of Time: Contemporary Photographs at the National Gallery of Art, Acquired with the Alfred H. Moses and Fern M. Schad Fund. On view from May 3 through September 13, 2015, The Memory of Time explores the work of 26 contemporary artists who investigate the richness and complexity of photography's relationship to time, memory, and history. In this conversation recorded on June 14, 2015, artist Mark Ruwedel and exhibition curator Sarah Greenough discuss the significant contribution of his photographs to the exhibition and their place within the arc of his career.