David Alan Harvey’s photograph of a boy with balloons on a street in Santiago, Chile, was taken in 1997. It is included in Streetwise, a new collection of pictures from the archives of the Magnum agency. The Magnum name became synonymous with street photography in the 1950s and 1960s under the guiding influence of co-founder Henri Cartier-Bresson. The current volume pays homage to Cartier-Bresson’s black-and-white “decisive moments” and examines the way that that spirit has been taken forward, particularly after advances in digital photography and printing enabled a revolution in colour in the 1980s.

Harvey was elected into the agency – there is a voting process among the membership – in the year that this picture was taken. By then, as a staff photographer for National Geographic, he had been taking pictures for more than three decades. A principle subject was the Hispanic diaspora on both sides of the Atlantic – the “divided soul”, as he terms it, of Latin culture.

Harvey traces his vocation back to a long period of isolated convalescence he endured as a child after contracting polio. His ward had a single window, which he stared out of for several months; he came to understand it as his viewfinder. Taking that small square out with him into the world, his pictures, as here, are often concerned with little poetic moments of contradiction and the subtleties of framing. The horizontal planes of the parked cars on the tarmac are counterpointed with the airiness and rainbow colours of the balloons rising beyond the frame. The boy’s eyes catch those of the photographer, as if aware of the earthbound incongruities of his situation, ready for lift off.

Magnum Streetwise, edited by Stephen McLaren, is out on Thursday (Thames & Hudson, £28)