Ms. Buirski devoted her professional life to documenting the world on film, both in still photography and in moving pictures. After beginning her career as an editor at Magnum, the highly regarded photo cooperative, she became a picture editor at the New York Times and later founded the Full Frame Documentary Film Festival in Durham, N.C., in 1998.

Ms. Buirski established her own reputation as a filmmaker with the release in 2011 of “The Loving Story,” a documentary about Richard and Mildred Loving, the interracial couple at the center of the 1967 U.S. Supreme Court case Loving v. Virginia that invalidated state anti-miscegenation laws.

The film, which aired on HBO, received Peabody and Emmy awards and helped inspire the 2016 feature film “Loving” starring Joel Edgerton and Ruth Negga. Ms. Buirski was among that film’s producers.

The Loving Legacy: Five interracial couples tell their love stories in a state where it was once a crime for Mildred and Richard Loving to marry

In her documentary, she called upon extensive archival material to assemble a deeply personal portrait of Richard Loving, who was White, and Mildred Loving, who was part African American and part Native American.

“In a rich collection of 16-millimeter film, old news clips and still photographs, the Lovings don’t look like two people caught up in a cause, they seem like two people caught up in each other,” TV critic Alessandra Stanley wrote in the Times.

Ms. Buirski returned to civil rights history in later documentaries including “The Rape of Recy Taylor” (2017), about an African American woman who was gang-raped by a group of White assailants in Alabama in 1944 and, with help from activists including Rosa Parks, challenged the mores of the Jim Crow South by seeking justice in her case.

Ms. Buirski’s 2020 documentary “A Crime on the Bayou” resurrected a 1966 case that originated in Louisiana amid the desegregation of public schools. Gary Duncan, an African American man, witnessed what he believed to be an impending fight between some White students and his two young relatives. He intervened by doing nothing more than touching the arm of one of the White boys, he said, but was charged with battery in a case that ultimately went to the Supreme Court.

Ms. Buirski delved into the cultural history of the United States in films including “Afternoon of a Faun” (2013), about Tanaquil Le Clercq, the majestically talented American ballerina who was paralyzed by polio in 1956, and “By Sidney Lumet” (2015), about the celebrated director of films including “12 Angry Men,” “Serpico,” “Dog Day Afternoon” and “Network.”

Ms. Buirski interviewed Lumet for the documentary before his death in 2011. Both the Le Clercq and Lumet films were presented on the PBS series “American Masters.”

Ms. Buirski’s most recent film was “Desperate Souls, Dark City and the Legend of Midnight Cowboy” (2022), about “Midnight Cowboy,” the 1969 Academy Award-winning drama directed by John Schlesinger and starring Jon Voight and Dustin Hoffman that became a cultural touchstone of the era.

“She’s telling you about the making of the movie, but she’s using it as a way into a much bigger set of themes — politics, culture, homophobia,” Glenn Frankel, a former Washington Post reporter and the author of the book “Shooting ‘Midnight Cowboy,’” said in an interview about Ms. Buirski’s work.

For her part, she said she saw “Midnight Cowboy” as an illustration of the power of film.

“One of the reasons I made the movie is I wanted to excavate why people were so touched by it back in the day and continue to be,” Ms. Buirski told the Desert Sun of Palm Springs, Calif., earlier this year. What she tried to bring to the documentary, she continued, “was the sense that films that have lasting power are not made in a vacuum. What was it that surrounded that film? What happened in that era that made that film inevitable? What kind of impact did it have on the next era?”

Nancy Florence Cohen — she was one of three daughters, including a twin sister — was born in Manhattan on June 24, 1945. Her father was a paper manufacturer, and her mother worked in various jobs in interior design.

Ms. Buirski grew up in New Rochelle, N.Y., and was a 1967 graduate of Adelphi University in Garden City, N.Y. After her time with Magnum, she spent more than a decade at the Times, including as a picture editor on the international desk.

In an obituary, the Times credited Ms. Buirski with selecting for publication the image that received the 1994 Pulitzer Prize in feature photography. Shot by South African photojournalist Kevin Carter amid famine in Sudan, the image, which ricocheted around the world, showed a starving girl collapsed on the ground en route to a food distribution center as a vulture eyed her menacingly.

Such was the response to the photograph, the Times reported, that the newspaper subsequently printed an editors’ note explaining that after the photo was taken, the girl resumed her walk to the food center. The photographer, who shortly thereafter died by suicide, scared away the vulture.

In her own photography work, Ms. Buirski published the 1994 volume “Earth Angels: Migrant Children in America,” a collection of images that a Times reviewer placed in the tradition of Depression-era photographer Dorothea Lange.

Ms. Buirski led the Full Frame Documentary Film Festival until 2008. Hoping to direct a film of her own, she settled on the subject for her first work when she read Mildred Loving’s obituary that year in the Times.

“They may have been reluctant heroes and they may have been unsung heroes,” Ms. Buirski told The Washington Post of the Lovings, “but they are heroes nonetheless.”

Ms. Buirski’s marriages to Peter Buirski and Kenneth Friedlein ended in divorce. Her sister Judith is her only immediate survivor.

“My films are about justice,” Ms. Buirski once told the New York Observer, reflecting on the themes that ran through her work. “My films are also about empathy,” she continued. “We come to understand other people’s lives even as we gain a deeper understanding about ourselves.”