Belle,” directed by Amma Asante, opens on May 2 (Fox Searchlight).

WHY IT MATTERS: The film takes an original approach to 18th century slavery, making the troubling point that it was the foundation of a region’s economic system — yet the topic is handled as if it were written by Jane Austen. As Variety’s Justin Chang wrote, the two elements make a “surprisingly elegant and emotionally satisfying fit.” The film is based on the true story of a woman born to an aristocratic English father and a black slave, who struggles to figure out where she fits in. Says Asante: “I started studying Austen in an adult-literature class. I was taken by the way she was able to pack a punch by using wit and humor in this genteel world of 18th century English society. And I wanted to transpose that in a period movie.”

ORIGIN OF FILM: “The BFI and the U.K. Film Council sent Damian (Jones, the film’s producer) to me” with a postcard and a script, Asante says. “They told him I was completely obsessed with the 18th century and said, ‘She needs to get this out of her system, and we think this is the right project.’ ” Asante and Jones began work using the original script written by Misan Sagay (who also scripted the Halle Berry ABC mini “Their Eyes Were Watching God.”)

THE POSTCARD: Taken from a portrait of Dido Belle and Lady Elizabeth Murray, which is housed in the art collection of the Earl of Mansfield. “I came onboard on the basis of the portrait,” Asante says. “I did lots of research to find out who this girl was, why she was there, why she looked like an aristocrat at a time when everyone who looked like her was probably a slave. And who was brave enough to commission a painting in which a white person and a person of color are of equal (standing)? I looked at the painting and saw a combination of history, politics and art in a single image.”

COMPLEXITY: “I am completely fascinated with Lord Mansfield (played in the film by Tom Wilkinson),” the director explains. “There could be 10 movies made about him, he was so complex and very conflicted. I would sit down with Tom and say, ‘Here is the information we have, and here’s what we’re doing with it, in the context of the script.’ ”

AUDIENCE REACTION: “We premiered in Toronto and had a three-minute standing ovation, which took our breaths away,” says Asante. “The only thing missing was my father, who passed away when we were making the movie. He would have savored it. Other than that, it was a perfect moment.”