Beyond life's dark edges ... Nan and Brian in the bed, 1983, part of Nan Goldin's The Ballad of Sexual Dependency  "One of the reasons I supported and like all the photographers in the show I've curated," writes Nan Goldin, in her catalogue introduction to the 40th Arles photography festival, "is that they seek to express their own truths."  Those truths tend to be of the hard-hitting variety: the photograph as a record of survival, a testament to - and defiance of - the darkness that often attends lives lived beyond the boundaries of so-called normal society. Goldin's most celebrated work, The Ballad of Sexual Dependency, is an epic semi-autobiographical narrative of survival, part installation, part ever-evolving stills-based film. It has become a touchstone for those who seek to lay bare their lives with a camera.  Perhaps because of the surfeit of confessional imagery on display, though, it was the work of Duane Michals that proved the most crowd-pleasing, but his one-joke narratives have always left me cold. I was more intrigued by the new work of another American hardcore veteran, Eugene Richards. Having made his name with his black-and-white urban reportage, his belated move to colour dismayed some of his faithful at Arles, but it seemed to me to be a successful reinvention rather than a late mellowing out.  Taken from his recent book The Blue Room, Richards's large colour prints of abandoned houses and landscapes in the American south were evocative and elegiac. In one, called simply Corinth, North Dakota, a sprinkling of snow that has blown though a broken window lies across an old mattress. In another, called Brickeys, Arkansas, an electric cable hangs forlorn from a portrait of Martin Luther King, on top of which some birds have built a nest. This is William Eggleston's weird southern gothic reworked as a remembrance of things long gone.  The centrepiece of this year's festival is a huge show entitled Nan's Guests, which includes reportage by the likes Jim Goldberg and Boris Mikhailov, all of it graphic and unsparing. Goldberg's images from his book Raised by Wolves record the lives of teenage runaways in San Francisco. As testaments to survival go, this one is powerful and poetic.  Mikhalov's photographs of Ukraine just after the fall of the Soviet Union are blue-grey in tone and painterly in their composition. They look like they belong to another postwar era: people huddle together, rush about, or stand alone, seemingly paralysed by uncertainty, as one world order collapses and a new, even more uncertain, one begins.  The main talking point of this year's Rencontres d'Arles, though, was another Nan Goldin choice, the American photographer Leigh Ledare. His controversial show, Pretend You're Actually Alive, takes Goldin's way of seeing to a whole new level - or, if you wanted to be unkind - nadir. Described in the catalogue as "a searingly intimate investigation of the artist's complex and ambivalent relationship with his mother", Ledare's work angered some and intrigued others. Put simply, he photographs his mother, a relentless exhibitionist, in an array of sexually explicit poses. At one point, she seems to be having sex with one of his friends.  It is hard to know what to do with imagery like this, but Ledare's accompanying texts are intriguing and often engaged me more than the photographs themselves. In one of the festival's many discussion-based events, Ledare - who seems like a good-humoured and well balanced chap - spoke with some insight about his work, its cost, and the questions it raises about exploitation, voyeurism and, even, abuse. Not for the sensitive or easily offended, though.  Amid all this grimy realism, Swiss photographer Annelies Štrba's images of herself and her extended family provided a kind of sanctuary. Her projection Shades of Time was made up of grainy photographs that add up to a meditation on motherhood and mortality. Elliptical and impressionistic, her work repays close attention and intrigues in a quiet, cumulative and complex way.  The shortlist for this year's Arles Discovery Award for new photography was the strongest I have seen in years. At Thursday night's open-air projections show, Martin Parr argued passionately for his choice, Rimaldas Viksraitis, a Lithuanian photographer who cycles out to the villages near where he lives and photographs the locals. They seem to be an abandoned bunch, drinking until they fall down, dancing wildly and often taking their clothes off for his camera. The results are not pretty, but are - praise the Lord - unselfconsciously powerful.  Against all the odds I liked Don McNeill Healy's intimate fly-on-the-wall colour photographs of Dublin itinerants, though this particular turf is too well trodden to truly surprise. Raed Bawayah's black-and-white portraits of the inmates of a Palestinian mental hospital were powerful without being voyeuristic or exploitative. I also liked Sean Lee's sad and glamorous portraits of himself as a transsexual called Shauna, lost in Singapore's nocturnal demi-monde, and Yang Yongliang's photography-based reworkings of old traditional Chinese landscape prints wherein cranes and skyscrapers emerge on misty mountaintops. This, at least, is one possible way out of photography's current impasse - how to be meaningful in a world where there is simply far too much photography, and so much of it self-referential to the point of banality.  My vote for best newcomer went to Moira Ricci from Italy, whose work was both mischievous and moving. Five years ago, in grief, she began sifting though her late mother's family snapshots, and realised that, as she puts it, photography could become "the way we meet in illusion". Basically, she has since created a narrative in which she appears - as her grown-up, grieving self - in every family photograph, gazing intently at her mother.  The result is an evocation of loss and longing, yet on another level highlights the essential sadness of the photographic image itself. It is that unreturned gaze that unsettles, though. Here, then, is a photographic journey that is startling without being shocking, that has been manipulated but is not manipulative, and that questions the nature of photography itself.
Les Rencontres d'Arles 2009, France The photographic feast that is the Arles festival is 40 this year and as intriguing as ever, says Sean O'Hagan