“Since the photographer’s picture was not conceived but selected, his subject was never truly discrete, never wholly self-contained. The edges of his film demarcated what he thought most important, but the subject he had shot was something else; is has extended in four directions. If the photographer’s frame surrounded two figures, isolating them from the crowd in which they stood, it created a relationship between the two figures that had not existed before.
The central act of photography, the act of choosing and eliminating, forces a concentration on the picture edge – the line that separates in from out – and on the shapes that are created by it.”
John Szarkowski: The Photographers Eye, The Museum of Modern Art, New York 2009.