The Photo-Secession was the American arm of pictorial photography, conjured into existence in New York in February 1902 by Alfred Stieglitz. While organizing a photography show for the National Arts Club, he quarreled with its conservative members and swiftly assembled an invitation-only group to make his position look backed by many. Its creed: what matters in a photograph is not the subject before the lens but the photographer's manipulation of the image toward a personal vision. With Edward Steichen, Gertrude Käsebier, Clarence H. White and others, Stieglitz advanced the cause through the sumptuous journal Camera Work and, from 1905, the Little Galleries of the Photo-Secession at 291 Fifth Avenue, which also gave early American exhibitions to Cézanne, Picasso and Matisse. The group kept exhibiting under its name until about 1910; tired of Stieglitz's autocratic ways, members drifted away, and he formally dissolved it in 1917.
An advertisement for the Photo-Secession and the Little Galleries of the Photo Secession, published in Camera Work, No 13, 1906Public domain (credit: Edward Steichen) · source
Defining characteristics
Soft focus and deliberate darkroom manipulation over documentary sharpness