While science is slowly putting together the pieces to explain the functioning of our vision system, the basic nuts and bolts of classical photography have been known for years, although certain details remain the subject of some discussion. Just as in the human eye, classical photographic systems are composed of two separate, but interrelated processes – the basic black and white image structure and the finer points of color reproduction.
This first installment on the chemistry of photography is intended to introduce, in a simplified way, the basic concepts of silver halide photography. It will not delve into the physics of optics, the functioning of cameras and lenses, photographic techniques, non-silver processes, or the artistic aspects of photography. Nor will it go beyond a cursory mention of color photographic processes, which will be left for the future. Anyone interested in more detail is referred to the selected bibliographic material cited at the end.
A Brief History of Black and White Silver Halide Photography
Perhaps the earliest reference to the concept of silver-based black and white photography is that of J. H. Schulze who observed in 1727 that a mixture of silver nitrate and chalk darkened on exposure to light. The first semi-permanent images were obtained in 1824 by...