PHOTOGRAPHY / Goodbye Columbus: Tanya Harrod on images of a people seeing off a cruel legacy

THIS IS the anniversary that no one with a political or social sensibility has been able to enjoy. The Photographers' Gallery is marking, not celebrating, the quincentenary of Columbus's arrival in America with two exhibitions of South American photography. The first - Julio Etchart: The Forbidden Rainbow - contains an array of memorable images that stake out the whole continent as a place of nightmares. Corrupt and brutal military regimes thrive, pollution of the environment continues unchecked, the oppression of its indigenous populations is built into the political structures. Even where Etchart appears to be documenting pleasure, it turns out to be hectic, tragic and ephemeral. We are misled by a picture of a gaily smiling boy. He is, in fact, a young vagrant high on glue. He is playing at Russian roulette; the gun that he holds to his head is real.

Photography tests to the limits the business of making art out of life. It is so literal and at times oddly dumb and uncommunicative. Without its caption Etchart's boy could have been any child at play. Documentary photography above all needs documentation, which is why the book that accompanies Etchart's photographs underpins the whole enterprise. Its essays mostly chronicle what we already think we know of Central and South America: facts and figures are piled up, horrors are magnificently and tragically confirmed.

None of this prepares us for the second exhibition. Desires and Disguises: Five Latin American Photographers treats many of the issues addressed by Etchart but with a revelatory tenderness and intimacy. The crucial difference is that these five photographers - from Argentina, Chile, Guatemala, Mexico and Panama - have all lived for long periods among the people whose lives they record. Once again the accompanying book, featuring interviews with the five, is crucial. We learn that Sandra Eleta has lived among the Congos - descendants of the liberated slaves of Portobelo in Panama - on and off for 20 years. Invariably posed, stylised and hieratic, her austere images - often of the Congos in their carnival regalia - may seem almost too aesthetic. In fact they take us to the heart of the show which reveals how oppressed, marginalised people heal themselves through rituals that simultaneously mock their oppressors and chronicle their history.

To document something so subtle is difficult. Maria Cristina Orive records the Mayan Indians' syncretic religious festivals in all their complex beauty. Arguably this very loveliness is troubling when we consider some of the nightmarish photographic images and reports that have come out of Guatemala. But there are ways and ways of dealing with a situation of despair. One of Orive's most powerful pictures shows an effigy of Judas Iscariot being borne through the crowds on Ash Wednesday. The unofficial beatification of Judas as San Simon - the Indians say he gave his 30 pieces of silver to the poor - turns Christianity on its head. It would be hard to think of a more subversive critique of the forced conversion of the Mayans by their Spanish conquerors.

Again and again these photographs show people empowering themselves, whether they be the Chilean transvestites, gypsies and circus people recorded by Paz Errazuriz or the members of the Mexican migrant street gangs of Los Angeles caught with such tenderness by Graciela Iturbide or Sara Facio's boulevardiers in Buenos Aires. Despite poverty and oppression these people never seem to be mere victims. Instead we see them dressing up, taking command of the street, dancing, praying and caring for their children.

Of course to record lives at such a level of intimacy demands great patience and sensitivity. It can be an unnerving experience to be photographed. And some of the greatest documentary photographers are clearly untroubled by the problem of the intrusive lens. They work on a war footing, shooting their way through rolls of film. Often war itself is their subject matter. These are stolen images indeed and remind us how macho the language and practice of photography can be and how the modern camera bears more than a fleeting resemblance to a highly engineered piece of weaponry. The fact that these five photographers all happen to be women is no accident. In most of the photographs in Desires and Disguises the subjects gaze out at us with unconditional trust. And as a result we have here a kind of celebration - certainly the most convincing one I have seen so far in this largely botched and flawed year of the quincentenary.

'Julio Etchart: The Forbidden Rainbow' and 'Desires and Disguises: Five Latin American Photographers' until 3 and 10 Oct. Catalogues edited by Amanda Hopkinson and published by Serpent's Tail at pounds 14.99 and pounds 10.99.

(Photograph omitted)