After the dry lab, Petiot-Groffier’s wet lab had been found in his former residence – completing the discovery of the world’s oldest photographic lab.

UA photographic lab – even the world’s oldest – may hide yet another one, as Pierre-Yves Mahé could experience himself lately, and with great pleasure. Earlier this year, the director of the Niépce House in Saint-Loup-de-Varennes already found a real treasure. The latest heir of Joseph-Fortuné Petiot-Groffier’s had discovered in his family residence in the Chalon region his predecessor’s photographic lab – hidden away behind a door on the second floor, which had not been opened for 152 years. Thanks to his decision to confide this surprising discovery to Pierre-Yves Mahé, the oldest intact lab – a photographic treasure indeed – had been made accessible again (see also our article on May 29th, 2007).

Under the emotional impact and with the urge to make an inventory of the hundreds of ancient objects found in the dry lab, Pierre-Yves Mahé didn’t make any attempt to find the missing part to the lab in the house. For there was obviously an important part missing, which couldn’t be hidden away that far.The dry lab allowed Joseph-Fortuné Petiot-Groffier to work on his photos, but in no way to develop them: the wet lab – the core to photographic development – was missing.
During a trip to the US, Pierre-Yves Mahé presented his discovery to the researchers at George Eastman House, who – fascinated by the finding – are equally intrigued by the question as to the whereabouts of the wet lab. Back to France, Pierre-Yves Mahé thus decided to look for the missing part. With Petiot-Groffier’s heir, he searches the house, room by room, from basement to the top.
In a simple storage room, the famous missing part is to be found – eventually. On the first floor, behind two large swing-doors leading to a room plunged in darkness. This room had been used for decades to store away things. In one corner, at its end, one discovers a sink; next to it, there seems to be a window, hidden away, carefully sealed off, preventing any light to enter.
On one of the shutters, a small hatch can be opened to let pass the light through a red filter – the very same inactinic red that is still used in today’s photographic labs, as it prevents film from reacting with its light.
“Looking at this from close-up, one can almost imagine Petiot-Groffier work here. One sees him fight against the intrusion of light, looking at his elaborate ways of darkening the room. A first wooden plate, made-to-measure by a carpenter, closes the window, but wasn’t waterproof enough, which explains the felt used to seal it off. As to the small hatch, it has been attached by a piece of string and felt, to obtain the best result possible”, Pierre-Yves Mahé explains.
A result as perfect, actually, that no-one could have ever guessed that there was a window hidden away in this very room. However, this was not the only secret of Petiot-Groffier’s rediscovered wet lab: Pierre-Yves Mahé equally found certain accessories that were missing in the dry lab, in particular some inactinic lamps, which allow to illuminate the photographers’ environment without affecting their work.

Petiot-Groffier’s residence seems thus to have disclosed all of its secrets by now, but there remains more than enough work to be done for the researchers to analyze them entirely. They now possess his entire photographic lab – intact – as it used to be from 1840 to 1855.

C. Saulnier