Pittsburgh 1950: Previously unseen images by Elliott Erwitt, a giant of American photography

Elliott Erwitt is one of the giants of American photography, with a string of Lifetime Achievement Awards and more than 20 retrospective photography books to his name. Years before he found fame as a Magnum photographer, he was commissioned to document the city of Pittsburgh as it underwent major redevelopment in 1950, transforming it from a neglected industrial city into a clean, modern metropolis.

Many of the images he took as a 22-year-old aspiring photographer lay forgotten in the back room of a public library for decades until a history student at the University of Pittsburgh chanced across them in 2011.

When Erwitt began to photograph Pittsburgh, it was heavily associated with the steel industry, fuelled by rapid immigration in the first half of the 20th century from Europe and African Americans from the rural south. Demand for steel during the war meant the mills operated 24 hours a day, resulting in high levels of air pollution. Erwitt captured the dirt and the grit of the old city, the new buildings of the city's rebirth, and most importantly, the individuality of its residents.

Erwitt had been commissioned to photograph Pittsburgh by Roy Stryker, best known for his work with the Farm Security Administration (FSA) in the 1930s, commissioning photographers such as Dorothea Lange and Walker Evans to document the American Midwest. Although he was notorious for giving his photographers shooting scripts, Stryker gave Erwitt free reign to photograph the city as he saw fit.

Erwitt was drafted into the army in Germany just four months after arriving in Pittsburgh, so was forced to abandon the project, leaving his negatives behind. They were held at the Pennsylvania Department of the Carnegie Library of Pittsburgh for decades.

These images of a city in flux have been compiled in a new book: Pittsburgh 1950 by Elliott Erwitt, published by GOST Books. The majority of the photographs in the book have been neither published nor exhibited before.