Louis Armstrong, 1956, by Michael Peto. Photograph: Michael Peto/Observer/NPG  Michael Peto died too early, at 62, on Christmas Day 1970. His stepson (also Michael), then studying at Dundee University, donated his father's collection of photographs to the college in 1971. Heavy crates were delivered. There all the prints and negatives were carefully cleaned by an archivist, and then just… languished.  Michael, born Mihály Petö in 1908 in the village of Bata, Hungary, had been a great of 20th-century photojournalism. Part of Hungary's absurdly talented diaspora that fled before the Second World War, he was employed by the Observer in 1949 and went on to chronicle, with a clear and perfect authenticity, the next two decades. Among his photographs are the greats of the period, but he was also documenting everyday life.  Patricia Whatley, Dundee University archivist explains: "He sounds like an astonishing man. Those decades were so crucial – to art, to politics – and Michael seemed somehow, always, to have been there."  Whatley, with others, are overseeing the restoration of the Peto collection. No fewer than 130,000 vintage prints and negatives were delivered that day in 1971. There is a drive to get them digitised before they crumble. A fundraising effort is under way, under the patronage of the actor Brian Cox and with the support of the Observer. Negatives tend to rot with exponential speed.  This year there are exhibitions of the prints at London's National Portrait Gallery and the New York Public Library. Next year his portraits of world leaders and political figures will line the halls of the Scottish Parliament. And in the meantime Whatley and her team continue to process the rest of the 129,000 Peto prints.  Michael Peto Photographs: Mandela to McCartney is on from 17 September 2013 to 31 May 2014 at the National Portrait Gallery, London (npg.org.uk/whatson). For more information go to dundee.ac.uk/petocollection
Michael Peto was one of Britain's greatest photojournalists. We look into his remarkable archive and the campaign to save it