When hut conservators removed a "congealed mess" from Robert Falcon Scott's historic hut at Cape Evans in Antarctica, they had no inkling their find would turn out to be precious images of Ernest Shackleton's support party.
"We didn't think it was of any note," said the Antarctic Heritage Trust's executive director, Nigel Watson.
Only when conservators got to work on the small, wooden box of material at Scott Base did they discover they had stumbled upon a set of developed photographic negatives.
The cellulose nitrate film sheets were brought back to New Zealand last year, where photographic conservator Mark Strange began the painstaking task of separating and cleaning the sheets of film, removing mould and consolidating the image layers. Twenty-two images were recovered.
They are photographs taken by the Ross Sea party of Shackleton's 1914-17 Transantarctic Expedition. The explorer intended to make the first crossing of Antarctica, but instead his ship was crushed by ice in the Weddell Sea, leading to an epic of survival.
The Ross Sea party laid depots of food and equipment to supply Shackleton's party but also suffered its own crisis. It was planned their ship the Aurora would spend the winter offshore, with most of the party on board. However, a blizzard blew the ship out to sea in May 1915, stranding on Ross Island 10 men who spent time living in Scott's Cape Evans hut. They were rescued by the Aurora in January 1917, although three men had died.
The box of negatives was found in the dark-room of Herbert Ponting, the photographer on Scott's 1910-13 expedition. Mr Watson said although many of the images were damaged, McMurdo Sound landmarks were visible in the photographs.
"It's an exciting find and we are delighted to see them exposed after a century. It's a testament to the dedication and precision of our conservation teams' efforts to save Scott's Cape Evans hut."
The identity of the photographer was unknown, he said, although the pictures might have been taken by the Ross Sea party's photographer, Arnold Spencer-Smith.
* 1901-04 Scott's first expedition reached 82 degrees south
* 1907-09 Shackleton's expedition reached 88 degrees south
* 1911 Amundsen's expedition was first to reach the South Pole in December 1911
* 1910-13 Scott's party reached the pole in January 1912 but died on the return journey
* 1914-17 Shackleton's Transantarctic Expedition. The Endurance was crushed by sea ice in the Weddell Sea. The Ross Sea party laid supply depots for the expedition on the other side of the continent.