Photographic chemistry has long been a complex combination of inorganic metal-halide and organic chemistries and polymer science. We at the P.R.I, have managed to add biology to this stew.

Silver has long been known as a toxicelement to microbes, and so used as a drug to kill bacteria. But there are bacteria that can survive in environments high in silver. It has been reported that some bacteria can accumulate up to 25% of their dry biomass as silver, and so acquire resistance to the toxic effects of silver. Also, a recent article in the Proc. Nat. Acad.Sci. describes the intracellular deposition of silver grains in such shapes as hexagons and equilateral triangles.