The Metropolitan Museum of Art and the Studio Museum in Harlem announced Tuesday that they would share ownership of the archive of James Van Der Zee, a virtuoso photographer who over a 70-year professional career produced an unrivaled chronicle of African American life in Harlem.

The archive, which will be housed at the Met, comprises about 20,000 prints and 30,000 negatives. The Met will acquire some 14,000 prints and 23,000 negatives from Donna Van Der Zee, the photographer’s widow, and the James Van Der Zee Institute, which was established to safeguard his legacy but has been dormant since the 1980s. Some 6,000 prints and 7,000 negatives are already in the collection of the Studio Museum, which will retain ownership of them.

The first and most urgent task is to preserve and scan the negatives before they deteriorate irreversibly, said Jeff L. Rosenheim, curator in charge of the photography department at the Met. Diacetate film from the early 20th century is unstable, and with age, the plastic base under the emulsion becomes brittle and detaches from the image-bearing layer. The Met’s conservation department encountered this problem previously with the first photographic archive it acquired, of Walker Evans, in 1994. In 2008, the museum also took possession of the archive of Diane Arbus. The Van Der Zee archive is its third archive.)

Mrs. Van Der Zee, with the Studio Museum, has administered the estate since her husband’s death. Rosenheim would not disclose the sum the Met paid her for the prints and negatives, except to say it was “a really nice amount of money.” The Met also obtained the copyright for reproduction of Van Der Zee’s images.

Operating out of a studio at 272 Lenox Avenue (now Malcolm X Boulevard), Van Der Zee, who died in 1983, provided portraits in which Harlem residents commemorated their momentous life passages: first communion, military service, marriage. He was there, too, for their passing, which he portrayed in a remarkable series of photographs of open-casket funerals.

“He is a central figure, a significant artist, in telling the story of people of African descent,” said Thelma Golden, director and chief curator of the Studio Museum. “The photographs are testaments to beauty and power, and he captured the Harlem community and the African American community in all its possibilities.”