Chim's career encompassed far more than taking photographs. As a founding member of Magnum Photos, Inc., a pioneering photo-cooperative that still thrives, he was a guiding force in its uncertain early years.
The idea for a new type of photo agency controlled by photographers, not editors, dated to the 1930s. Chim, just starting out in Paris, developed a close friendship with two young photographers, Robert Capa and Henri Cartier-Bresson, who were equally passionate about social justice and the integrity of their work. As Chim explained in a letter to his sister in late 1933, "We are trying to organize some kind of association of revolutionary-minded photographers."
Thirteen years and two wars later, Chim in 1947 received a telegram informing him that he had been named vice president of the newly established Magnum Photos, Inc. Chim, Cartier-Bresson, English photographer George Rodger, and (for a brief time) William Vandivert joined Capa, who spearheaded the project, as the founding photographers of the innovative cooperative.
Magnum's aim was editorial independence: rather than working on assignments handed out by magazines, Magnum photographers would generate and shoot their own stories and would retain copyright to their images. Magnum's offices, at first in New York and Paris, would write captions and then sell the stories throughout the world. Magnum photographers became known for their integrity, dedication, and individual expression.
Magnum was formed at the right time. Capa and Cartier-Bresson were already famous, and picture magazines, whose circulation and revenue increased markedly in the late 1940s and 1950s (before television's domination of journalism), had an endless appetite for quality photography.
As Magnum grew, Chim assumed greater organizational powers, planning group projects, reorganizing the Paris office, and traveling around Europe to talk to editors and agents about Magnum stories and guarantees. In 1953 he was placed in charge of Magnum's complex finances, which he proved deft at managing. For Chim, who was unmarried and had lost his parents in the war, Magnum became an ersatz family. When tempers flared, Chim, with his cool demeanor, played mediator and peacemaker.
May 1954 proved a tragic month for the photo agency. Capa, Magnum's president, stepped on a mine in Vietnam and was killed. Almost simultaneously word reached the agency that Magnum photographer Werner Bischof had fatally plunged into a gorge in the Andes. Magnum was rocked, and Chim, despite losing one of his oldest and closest friends, took matters in hand to ensure its survival. As Magnum photographer Eve Arnold noted, "Magnum was now in disarray .Chim helped forge ways and means for us to continue. Without his concern I question whether we would have stayed together."
Chim assumed the presidency, which he held until his own death. In his brief tenure, he took steps to professionalize Magnum that had a lasting impact, including working out issues of money and control. But he also helped shape Magnum's identity. In an essay he wrote for the 1956 photokina photography fair in Cologne, where Magnum had its first representative group exhibition, Seymour explained what Magnum photographers had in common: "The Magnum group cannot be considered a homogenous school of photography. It includes all varieties of individual talents, different technical approaches, and creative interests. There is, however, some unity, difficult to define, but still existing. There is a great affinity among Magnum photographers in terms of their photographic integrity and respect for reality, their approach to human interests and search for emotional impact, their preoccupation with composition and layout, and their awareness of narrative continuity."
Seymour's affection for Magnum was consuming and infectious. But it is also what persuaded him to cover the Suez crisis, where he would be killed. When colleagues tried to dissuade him from going to Egypt, he explained, "I feel we cannot stay out of world events if we are to grow as a group in photography."