Arts: A little more than you really wanted to see?

A show by six documentary photographers celebrates the intimacy of voyeurism.

Homo, Lesbiennes, Hetero, Travestis, Amateurs: the blue neon sign may be written in French, but its meaning is clear enough. To the right, a grey-haired, suited man disappears down the stairs into darkness and a world that we as onlookers can only guess at, his descent recorded by the photographer Vicki Wetherill who spent six months in the Paris red- light district furtively snapping the furtive world around her; a voyeur stalking voyeurs.

On the surface, at least, the peep- shows are surprisingly glitzy: a mass of sequins, neon and luscious velvet curtains all shimmering away in a shameless attempt to lure in the punters. Another doorway is covered by floor-to-ceiling dark-red sequinned curtains that you half expect to sweep back revealing a high-heeled chorus line, but the hand seen clutching the curtains together and the trainers just visible below its hem-line bring you back to reality.

"The curtains look like they are women's skirts and are suggestive of a woman's vagina," says Wetherill. "When the men push their way through the gaps in the curtains, you get a brief glance at the interior world."

Substance, curated by Rankin, the photographer and co-founder of the trend-setting style magazine Dazed & Confused, is a small but powerful exhibition showing the work of six young documentary photographers.

"I love all styles and genres of photography, but the one that has the most substance is documentary," enthuses Rankin. "Photography was invented to document things in the most realistic way," he adds, the words tumbling out with a no-nonsense urgency, laying bare his all-consuming love for the medium.

"Portrait photography is about being able to understand the person and feel for them, to have an empathy with the subject - and that's what drew me to all these students. So many photographers become photographers for the lifestyle - they don't do it to communicate. This group, however, all wanted to relate something to the viewer. I think it is important to empathise with the subject and then to collaborate with them."

And, standing in the middle of the small gallery space, the feeling of being an invisible presence in other people's lives is almost overwhelming: the sordid glamour of the peep shows; the intimacies of family life, usually hidden behind closed doors; stills from CCTV cameras which follow our everyday moves; and uncomfortable close-ups of bodily malfunctions. They are all captured on film and displayed for our consumption.

The Dazed & Confused gallery is easily missed. Rubbish bags are piled up outside, and you have to get nose-rubbingly close to the wire-mesh windows to get any sort of glimpse inside. Two of the six photographers are lucky enough to have their names scribbled in biro on the wall under their work, but after that you will have to fall back on the catalogue in order to find out who is who.

Rebecca Lewis has turned the camera on her own life and the mod scene in which she moves, and the immaculately turned-out mods are more than camera ready. Red patent shoes and glittering tights disappear up a dust- and dirt-encrusted staircase, while another figure, with the head and lower legs cropped out, stands facing the camera, allowing the viewer the chance to stare and stare at the little red patent bag, minute mini-suit and the tops of her knee-length boots. Keyhole compositions such as this allow the inquisitive outsider to indulge themselves to the full.

The success of fly-on-the-wall documentaries, which appeal to curtain twitchers the country over, play on the public's natural nosiness. Everybody, it seems, wants to know what's going on behind their neighbours' closed doors and in other social worlds that are usually out of bounds. Jonathon Baker has thrown open the doors to his own home and invites us in. Here is his father on the toilet, there another family member in the shower, and over there is the family cat leaving the room, arse in the air.

It is undoubtedly intimate. This is real life caught on film, but the humour and scatological elements are almost too voyeuristic - family jokes that have nothing to do with the outside world, and should perhaps stay that way.

Gordon MacDonald has taken his camera as close as possible to his subjects, putting them under the microscope and then blowing them up large for our inspection. Common Complaints gets stomach-turningly close to skin disorders, the timing and cause of the eruptions added in the title to make the point that these are outward signs of what the body is going through. The detail of the images is unforgivingly sharp and exposes human frailty and imperfections that people usually prefer to hide.

Cheese sandwich (Spot) throws a spot the size of a cabbage at the viewer, its putrid yellow head as large as a ping-pong ball, and surrounded by tough, jutting, twig-like bristles. Rinsing in the Bath (Dandruff) shows a head of hair matted with flakes of dandruff the size of 50 pence pieces, and New Year's Eve (Cold sore) is a raw, volcanic explosion of flesh with yellow and black encrustations around the crater.

Informative documentation? Yes. Fascinatingly voyeuristic? Yes. Although possibly more than you want to see. Substance, curated by Rankin, Dazed & Confused Gallery, 112-116 Old Street, London EC1 (0171-336 0766). Monday to Friday, 10am-6pm, until 30 July