Alfred Stieglitz (1864–1946) is celebrated for the pioneering exhibitions of modern European art that he presented at his gallery 291 in New York between 1907 and 1917 and for his support of American artists. Photography, his greatest passion, was not only the medium he used to express himself, but also the touchstone he employed to evaluate art. Donated by the Clark Collection to the National Gallery, Untitled (Helen Kastor Fleischmann), c. 1917, is a stunning platinum/palladium print that helps to expand our understanding of the evolution of Stieglitz's art.

Through the exhibitions he organized, the periodicals he published, and the example of his own work, Stieglitz played a central role in the acceptance of photography as a mode of artistic expression. He also championed the work of numerous American photographers from Gertrude Käsebier, Clarence H. White, and Edward Steichen to Paul Strand and Ansel Adams.

At the time Stieglitz took this picture, Helen Kastor Fleischmann, a wealthy cutlery heiress, was married to Leon Fleischmann, a poet and one of the many artists, writers, musicians, and intellectuals who frequented Stieglitz's gallery; she later married James Joyce's son, Giorgio. Although Stieglitz described her in a 1917 letter to Georgia O'Keeffe as "pretty, vivacious," he chose to focus on Fleischmann's hands and legs rather than on her face. Most likely made in 1917, the picture is an early example of Stieglitz's radical rethinking of the nature of a photographic portrait. Inspired by Auguste Rodin, Marius DeZayas, Francis Picabia, and other modernist artists, Stieglitz realized that a portrait need not capture a subject's face but could allude to their character by portraying other elements of their body, or even abstract attributes. This was an idea he explored further in his portraits of O'Keeffe and others made from 1918 through the early 1920s.

After his death in 1946, his widow, O'Keeffe, assembled the foremost collection of his photographs and donated it to the National Gallery in 1949 and 1980. Numbering more than 1,600 pictures, the Key Set includes one print of every mounted photograph in Stieglitz's possession at the time of his death. If there were different kinds of prints made from the same negative—platinum, palladium, gelatin silver, photogravure, or carbon—or different croppings, O'Keeffe put the finest examples of each into the Key Set.

The Key Set is an exceptional and unrivaled collection of Stieglitz's art, but he did not always save a print of every photograph he made. In a few rare instances, important pictures have emerged that were not represented in the National Gallery's collection, such as Untitled (Helen Kastor Fleischmann).