Camille Silvy was a pioneering but little-known photographer.
His photographs, from Algiers, rural France, Paris and London, give an intriguing snapshot of nineteenth-century life.
They are often political.
Reading the First Order (pictured) shows a group of workers in Paris reading a message from Napoleon III, then at war in Italy.
Two men turning away from the sign represent revolutionaries opposed to Napoleon.
This exhibition features over 100 images, many not shown since the 1960s.
The National Portrait Gallery, London until 24 October, £5/£4.50/£4. Visit www.npg.org.uk