Once a pile of junk at the back of a suburban shed, the world’s largest glass plate negatives of Sydney Harbour have just been added to UNESCOs International Memory of the World Register.

Captured in 1875, the three views of Sydney Harbour, the largest of which measures over 1.6 metres wide, show a harbour city still surrounded by bush, and with many other natural features still visible, most of which nowadays would be almost urecognisable to most residents.

These negatives are now part of only five other inscriptions from Australia that currently sit on the World Register.

The images were created for what we would call today an advertising campaign, selling the wonders of Sydney Harbour to an 1870s world. 

Funded by wealthy German‐born entrepreneur Bernhardt Otto Holtermann (of the Holtermann nugget fame), who after teaming up with a professional photographer called Charles Bayliss, built a 23-metre high tower with a three metre‐square room at the top that became a giant camera, allowing Holtermann to document his adopted home to the world, through what was then the new medium of photography.

By using the wet‐plate (or collodion) photographic process, the duo went on to create the world’s largest pictures, eventually touring with them all over the globe and promoting the relatively young city to the outside world.

Held by the State Library of NSW, the entire Holtermann collection includes over 3000 (normal-sized) glass‐plate negatives, and includes images from gold rush towns in NSW and Victoria between 1870 to 1875, a collection that was added to UNESCO’s Australian Register in 2013.

Part of a hoard of 3500 glass plate negatives that was discovered in a garden shed in Chatswood in 1951, these giant negatives are the first listing for the State Library of NSW on the UNESCO World Register.