(Lewis Hine / US National Archives)

As well as creating a body of work documenting American child labor, Lewis Hine was also responsible for this now-iconic image – an example of Hine’s photographic adjustment away from realist documents and towards a more compositional approach.

Hine’s picture of a power house mechanic – an example of his “Work portraits” – had a deliberate intention behind it. Photographing for the U.S. Work Progress Administration, Hine saw the significance of the human worker being overwhelmed by the proliferation of mechanisation. Here, Hine attempts to redress the balance, placing the worker – and the machinery of his body – at the centre of the power house.