|Franco's studio, Lower Manhattan, January 26, 2015|
Especially you won't see them when the electric power grid in the city is flooded with rising seawater, as happened in parts of lower Manhattan during the recent snow emergency that some wanted to call a blizzard. In Franco Marinai's downtown neighborhood the power outage left many without light, but these are the same folks who had survived Hurricane Sandy in 2012 and they knew how to cope. They vowed to continue making chemigrams even if by candlelight. In block after block, candles flickered into the night as chemigramists studied their trays, snatching and pushing photo paper, oblivious to the thickening snowfall outside and the strange silence of the darkened streets.
It was a good time to reflect on the importance of light in the process. When a packet of light, called a photon, strikes the photographic emulsion, it passes quickly through (at the speed of light!) until it hits a molecule of metallic silver. These molecules are actually ions, or charged particles, embedded in a crystal lattice of many such particles along with ions of bromine or chlorine. If you could see these crystals they might look like this:
|silver halide crystals in a gelatin emulsion, courtesy Kodak|
Our photon gets absorbed by the silver which then ejects an electron, carrying a negative charge, thus setting in motion a cascade of energy transfer events that will lead to a local region of stable, pure silver. This becomes known as the 'latent image'. It's latent which means you can't see it, at least not right away. But if you subject it to the development process, all these energy transfer events are amplified greatly and of course by then you will see it as a black shape. But we're getting ahead of ourselves. Latent is what we want for chemigrams. While developing it all at once might make a nice photograph, for us as chemigramists the opportunity would have been squandered. Rather, we want to finesse the process by re-shaping the crystals, breaking them up and rearranging them, with repeated assaults of fixer and developer. These chemicals can be thought of as acting as tiny chisels. Through this, the silver gradually gets reconfigured into alternate forms, forms that reflect light in a variety of wavelengths, from long to short, from red to blue and purple, and acquires these colors for our eyes as if they were its own.
Just like in photosynthesis, that other great photo-based process (perhaps more fundamental to life), it all starts with a photon. Franco knew this, and was able to keep producing work throughout the blizzard.
His website is http://www.marinai.com.