Chemical reaction

I was in town today and just happened to be walking past an empty shop which gets used for various projects on an occasional basis and today there was a photography project going on inside.  Two photographers were using old cameras and the tin plate process to photograph members of the public.  I couldn't resist going in!  So this is a tin plate photograph of me in the developing tray and the photograph was taken by Laura Peters.  I love digital photography but seeing an image appear like this is magical in a way, even though I know it can be explained as a chemical reaction.
The extra shows the poster for the project.