It was 1981 and Donna Ferrato wanted to photograph people in love. More precisely, she was interested in swingers who frequented New York's sex clubs.

And so, she found the perfect polyamorous couple to focus her lens on. They were happy, wealthy and fashionable, and welcomed her into their New Jersey home for weeks at a time so she could intimately document their lives.

But one night, she witnessed something entirely unexpected: The husband brutally attacked his wife, striking her in the face. Ferrato snapped a photo thinking it would make him stop. It didn't.

She sat on the undeveloped film for months, weighing what to do. Then, she began what has come to define her life's work: documenting the horrors of domestic violence.

Armed with her camera, she crossed the country visiting domestic violence shelters, emergency rooms, batterers' programs, police stations and prisons. In 1991, she published Living with the Enemy , a book that, for the very first time, revealed in shocking detail the private violence that went on inside American homes.

A few years later, her iconic photo of a woman with two black eyes appeared on the cover of Time magazine . Now, in a new documentary by Time Red Border Film, Ferrato explains the trajectory of her career, and the woman from the couple in those very first photos opens up about that night.

The Huffington Post caught up with Ferrato by email and asked her some questions about her work. Her answers have been edited for clarity.

How did you get involved in photographing domestic violence?

It was 1981. Before the AIDS epidemic when there was very little fear about random sex or hard drugs. I was working on a long-term project photographing the free-wheeling lifestyle of a fashionable New Jersey couple I'd met at a swinger's club in Manhattan. People were curious about Plato's Retreat, where the young and restless went to meet other like-minded couples.

I wondered who would participate, how husbands responded upon seeing their wives sexual with strangers, how it worked. I wanted to literally be inside the core of their relationships, to understand how their swinging lifestyle meshed with family responsibilities as they broke through social taboos.

It was not my intention to document domestic violence. I hadn't much thought about it, because it had not threatened my childhood. One night, four months after I was documenting this couple in their beautiful mansion, the husband attacked his wife (without apology or shame) in front of me and my camera.

I was shocked because he seemed to feel entitled to hit her, even in front of an outsider, because she was his wife.

Up until that point, I had been trying to show the beauty of people in love. Shocked that love could go so wrong, I became obsessed with documenting domestic violence. Driven to try to do something about it, I found that a camera was my best weapon.

What was the general public's reaction to the photos once they were released?

Much of my work was born out of frustration -- first because I felt powerless in the face of the violence I had seen, and second because for a long time no magazine would publish the pictures. No one realized how common domestic violence was. Women had no choice but to suffer in silence. Either live with it or run away, never be seen again. There was no discussion about it as an injustice to women. To me it seemed like women lost their rights as human beings when they got married.

As opposition to publishing these photographs continued, I dug in deeper, getting permission to ride with the police, live in battered women's shelters, hang out in emergency rooms. I often wondered, how could men get away with abusing women in such horrific ways?

At the time I didn't realize how ridiculously easy it was. Everyone colluded with the abuser. Blamed the woman. It was simple. When some images I made in Philadelphia while on assignment for the Philadelphia Inquirer were published, it was like a bomb went off. People were very shocked when they saw a real woman with black and blue eyes on the cover of their Sunday magazine. Finally the cat was out of the bag ... nobody could claim ignorance about the severity of this social problem.

Fortunately, back in the early '80s, there was a strong grassroots movement started by women to change legislation and to introduce laws with real teeth to hold abusers accountable. My photographs were the evidence they needed to raise money to do more public awareness campaigns, to strengthen the shelter movement, and most importantly to save women and children's lives.