And Now the Ensemble!!!
The Making of the Silver Gelatine Print
The photograph in the Sala Pittura of the Swiss Pavilion is probably the largest analogue black and white assembled photograph ever developed onto a wall: Five meters high, 58 meters long; a total of l 286 sqm silver gelatine print applied and developed directly on the wall. Here, the walls function as the photographic „paper“ for the collage of the three architect‘s offices. It sounds simple, it looks simple, it is not simple. If you want to develop prints you need a darkroom. Therefore first of all, the entire hall had to be transformed into a darkroom.
Moreover, to prevent the photosensitive emulsion from being completely absorbed by the walls, we first had to paint the walls with gelatine. Otherwise the images would seem to disappear into the stucco.
At that point, we were able start to print the collage onto the walls creating the huge panorama. It had to be separated into 12 single prints, each the size of 25 sqm.
Summer is not the ideal season for such large prints. 20°C is to be said ideal for developing prints but with a 25 sqm print everything changes. You have to work much quicker and the environment has to be kept much cooler. We therefore had to cool down the hall quite a lot. Outside temperatures were about 30°C with high humidity: a challenge for us and for the air conditioning.
After these preparations, the projector we used for printing was set up and adjusted to a height of 2.50 m. The next step was setting up the first exposure. After having established the exposure time it was the moment to get started with the printing of the images on the wall. The silver gelatine was applied with brushes since we wanted to give the images a particular liveliness and texture. After about 90 minutes the emulsion was dry and we could proceed: exposing the image, developing, fixing and rinsing.
A tray at the bottom fitted with a pump served for recollecting the fluids. A mobile scaffold enabled us to reach even the highest parts of the walls. We applied the chemicals with pressurised sprayers which are normally used for gardening. Photographic developers have the tendency to oxidate rapidly leaving yellow traces on the wall. The process of developing therefore had to be a quick one – not more than three minutes. Then we had to wash away the remaining developer before we could use the fixer. For rinsing the photograph – in order to wash out all chemicals – we used two big water hoses.
After approximately another 30 minutes we could finally switch on the lights and observe the result. What suspense!
For each print we needed a full day. It is one thing to do one print of this enormous size, it is another thing to make 12 of them match with each other. For each new print the adjoining areas had to be protected to prevent the photosensitive emulsion or chemicals from getting onto the already developed surrounding images. We had to work our way very accurately over the entire 286 sqm.
But the task was not over yet. Since the initially white emulsion had to be applied onto the white wall in dim red light, we encountered the need for some touch-ups. As we wanted the prints to have even tonality and consistent blacks and whites we went over the entire panorama with a bleaching agent to achieve these exacting results.
And we succeeded!
Michael Zirn in collaboration
with Claus Feldmann and Joachim Seinfeld