When Canadian documentary photographer Naomi Harris attended her first swingers party she wasn't sure what to expect. Sex was clearly on the agenda, but food? The venue was a club called Trapeze in Fort Lauder-dale, Florida, in a rundown part of town and Harris had gone along as a curious observer, accompanying a single male friend who needed her to gain access to the party. 'My first thought was: "Everyone here looks old enough to be my mum, that guy could be my dentist, these are ordinary people who liked to swing",' she says. And, as she soon discovered, they also like to eat.

'There was a guy with a big chef's hat carving out roast beef and serving potatoes,' she says. 'It was heavy, heavy food, and some people were going up for seconds. There was a bit of dancing and then about 20 minutes later everyone went off to a backroom and started having sex. I didn't find it sexy, I wasn't turned on at all, but I did think: "Wow what a project, no one has ever photographed this". That was back in 2002 and now, almost five years and 35 swingers' parties and conventions later, Harris has  just about completed this exhaustive project, which will be published as a book by Taschen.

Empathy & sympathy

The New York based, award-winning Harris, 34, made her name with an equally compelling long-term story, with an entirely different subject matter. That project focused on Haddon Hall, a retirement home for Jewish senior citizens in Florida. Harris moved into the residence for several months, becoming her subjects' friend and confidant and immersing herself in their lives.

'I was their surrogate grandchild and they were my surrogate grandparents,' she says. 'We were all getting something from the relationship, the photography was just a part of it. With the swingers I'm not sure if I got anything out of it because I don't play. The people find me entertaining and try and convert me, but it's a very different kind of relationship. So in some ways Haddon Hall was a more intimate project than the swingers.'

Both projects demonstrate Harris's considerable documentary and portrait photography skills, as well as her sympathy and open-mindedness. Many projects about senior citizens veer towards the condescending or sentimental, and it would be easy to judge the swingers, but Harris avoids both traps. Her images are sometimes very funny and sometimes very sad, but always deeply empathetic.

Harris originally studied fine art in Toronto, her hometown, but in her third year took a basic photography course and caught the bug. In 1997 she gained a place on the highly prestigious documentary programme at New York's International Centre of Photography, where, she says, she learnt everything she knows about shooting in colour. Kathy Ryan, the respected photo editor of the New York Times Magazine, saw the Haddon Hall project and was so impressed she commissioned Harris, more or less on the spot, to shoot a story on race in America. This assignment set her editorial career in motion, which in turn financed her long-term projects. For the past eight years or so Harris has combined commercial work with editorial portraiture, shooting everything from celebrities to obsessive gamers. Her images have appeared in publications such as GQ UK, The Guardian, Time, Newsweek, Marie Claire and Fortune.

The swingers project started almost by accident when she moved to Florida. 'In Miami I used to go to the nude beach and I would see the funniest things going on around me,' she says. 'There were people flossing their teeth in the nude, diabetics injecting themselves with insulin. So I started taking photos of what I saw on the beach, with people's permission of course.' Many of the nudists were also swingers, and getting to know them lead to her initial party at Trapeze. But even after that eye-opening experience, she didn't start documenting the swinging scene for about another year.

Gaining trust

The most challenging aspect of the project was gaining access to what is a very closed world and, once in, gaining people's trust. The participants are not stars, but housewives, electricians and insurance salesman - ordinary people with families who stand to lose a lot if their secret lives are exposed. Harris managed to open the doors though a combination of talent, chutzpah and persistence, as well as being prepared to go to any lenghths to get the picture, barring actually swinging. If the party is a bondage party, for example, Harris will dress the part - she has worn rabbit ears and often not much else. 'If it's a nude party, I will go nude apart from a big tool belt carrying my batteries,' she says. 'I've got a chord, with a big flash and my Contax 645. I look like Weegee in the nude.'

Harris is no shrinking violent, and it was her people skills that got the swingers onside. 'I meet a lot of photographers who don't listen or engage, yet they expect their subjects to give them something in return,' she says. 'I listen, I talk, I make jokes to break the tension sometimes. I'm interested in people.' She's also honest enough to admit that being a woman helps. 'If I was a guy forget it, people think guys are going to post the images on a website or do something sleazy. With me, they want to take care of me. That said, I have been to parties where I've been verbally abused and they've tried to break my camera. I've gone though a lot for this project.'

She's also seen a lot. Harris says that Martin Parr is a big influence and she certainly has his strong sense of colour and composition, combined with an unflinching eye. Her images swingers at play are graphic in detail, as well as content. These are not beautiful people: they are often overweight, sweaty and hairy - apart from around the pubic area, where both sexes obsessively shave. These are real people having sex. Sometimes the participants are in ecstasy, joking, having fun, clearly flirting with Harris; at other times they seem oblivious to her presence; and sometimes they look distracted, uncertain or inebriated. The images are intimate and erotic, and sometimes as mind numbing as bad pornography. They are a lot of things, but always honest, and Harris has clearly picked a subject that is going to get her noticed. 'I hope so, it better,' she says. 'I haven't given four years of my personal life and spent $60,000 of my own money for nothing.'

Subversion

The sheer number of parties and participants Harris has photographed is also striking: this is a subversive community, but it is also growing. There is a certain irony that while the Republican Bush administration has zealously tried to impose its moral restrictions on the United States, swinging has spread though the American heartland. Harris documented deathly pale participants at parties in Minnesota, and tanned swingers in California. She's photographed fornicating men in cowboy boots in Texas, and swinging conventions in Las Vegas that included a staggering number of participants.

The sheer numbers involved aren't gratuitous: Harris has included as many parties as possible in the project because she wants to present as complete a picture as possible of swinging in America. And there's a practical element too, because she was never quite sure what she would be able to document. In some instances, the crowd not only welcomed Harris but enjoyed playing out their exhibitionist tendencies. At others, it was clear that she was there on sufferance. But it's a small community, and word soon got round that Harris' intentions were genuine and that she could be trusted.

She got all her subjects to sign model release forms before shooting, using documents based on the porn industry standard model release. She also insisted that all her subjects presented photo id and that a third party witnesses their signatures. Once they had signed she gave willing participants a wristband, so that when the action heated up she could identify her subjects.

Portraits

Harris took more formal portraits of the swingers as well as action shots, photographing them in bondage wear, g-strings and fancy dress, or picking out genital piercings. Harris has an eye for the surreal and placed her subjects against the shiny wallpaper of the clubs or hotels in which they were swinging; juxtaposing mundane American interiors with a bizarre lifestyle to give her images a certain absurdity. The images are also often very funny, but unintentionally so.

'People can take out of my photographs what they want, but I am not mocking these people at all,' she says. 'I find them fascinating. They are ordinary people and the parties often take place in ordinary-looking hotels or clubs. Many of the swingers are Republicans, they are conservative in many ways and generally frown on drug taking. Many of them are churchgoers who simply have an unusual pastime. Most of America looks like these people. I don't feel grossed out by these individuals, but of course you become a little desensitised,' she adds. 'I'm watching people have sex and all I'm thinking is: "If that couple moved a little to the left, then the composition would be that much better". But of course I can't art direct people while they're doing it. Once this project is done, I really don't want to photograph anything to do with sex for a long time.'

In fact Harris says that she now can't wait for the project to end, but although it's been challenging, it's also been curiously life affirming. 'Swingers look after each other,' she says. 'It's a community. One guy's house burnt down and all his party buddies raised funds to rebuild his house. They aren't harming anyone or themselves. Whatever makes them happy.'