But after years of playing, he realised he had a remarkable collection on his hands, published now as The Children (Aperture, pound;30).
"I was struck by their intensity," he says. "Children who had been laughing and shouting only seconds before had become individuals who, through their clothes, their poses, their expressions and their eyes, were telling their stories with disarming frankness and dignity."
Many of the children in these black and white pictures (such as the boy in Sudan, above right) are in refugee camps, displaced by a familiar roll call of conflicts - Rwanda, Bosnia, Palestine, to name a few. Others are from oppressed or marginalised tribes such as the Yanonami in Brazil.
Their clothes could be a focus for a class project in their own right - a chunky indigenous Indian patterned sweater on a girl in Ecuador, leaflike earrings on two Yanonami kids in a jungle hammock, and a pristine restitched dress with the collar hanging off on a girl from Mozambique.
Each garment tells its own story of poverty, self-respect in adversity, resourcefulness, cultural survival.
But it's the eyes that make these pictures compelling. If there is such a thing as a life force, it can be seen in the light in these children's eyes. For others, such as a boy holding his sister against a mud-packed wall in Afghanistan (above, left), its dimness suggests a life snatched away.
Salgado, twice named international photographer of the year, is one of the best, and his pictures should not be missed.
Children's Portraits is part of Exodus: photographs by Sebastiio Salgado at the Barbican Gallery until June 1. www.barbican.org.uk