Portrait of a man, circa 1855, Boulogne. Photographer unknown. Gift of E E M Anderson estate, 1971. Te Papa

At 3pm on the 19th August 1839, a joint meeting of the Academie des Sciences and the Academie des Beaux-Arts, heard from the politician and scientist, François Arago, about the details of a process that produced unbelievably fine detail and extraordinarily subtle tonality.

Louis Daguerre, who had been working on a light-sensitive process for about 15 years, was not the sole inventor of photography but as his invention was fully disclosed and unpatented it was the first to become widely practised. Others had attempted to form images from a camera obscura, or as WH Fox Talbot described his attempts, to use ‘the Pencil of Nature’, but Daguerre’s process (thanks to an agreeable pension from the French government) was completely disclosed and so began a short period in photographic history in which the process was open-source.

The portrait (above), of the sisters Caroline and Sarah Barrett, is one of the earliest known daguerreotypes to have been made in New Zealand and it is also one of the earliest known photographic portraits of Māori. It is held in the collection of Puke Ariki museum in New Plymouth.

A daguerreotype is made using a sheet of silver-plated copper which is made light-sensitive with the vapour of iodine.  The plate is then exposed in a camera and the image becomes visible using the vapour of warm mercury. The daguerreotype process is still in use today and two notable New Zealand practitioners are Joyce Campbell and Alan Bekhuis.

Thanks to Mark Strange – Senior Conservator of Photographs at Alexander Turnbull Library, Wellington

Lissa Mitchell – Curator Historical Documentary Photography