Developers -- the chemistry of photography
Photography now is known for around 150 years and until recently with the advent of digital photography, the basic concept behind the photography has been the same for almost 150 years as well. Practical developments and improvements of processes have been tremendous over the decades, but the chemistry involved hardly has changed over all those years.
In this document, the chemistry of photography is covered, and at the end of the dicussion, several links to nice sites, recipes and processes are given.
Two basic types of photography have been developed in the 19th century and since then both of them have been brought to great perfection.
One process is based on silver halide chemistry, the other is based on ferricyanide chemistry. Both of these compounds are light-sensitive.
The silver halide based processes are at the basis of black and white photography, and also (combined with certain dyes) at the basis of modern color photography. The ferricyanide bases processes are at the basis of blue prints and also are known as cyanotypes. The latter process still has its value, but more in the artistic photography scene.
The chemistry behind both processes is described in detail in the following pages:
- chemistry of silver halide processes, black and white photography
- chemistry of ferricyanide processes, blue prints and cyanotypes
Some links, containing interesting background information, recipes and nice experiments are given below:
- http://wwwchem.csustan.edu/chem2500/labs/labintro.htm
- http://www.jackspcs.com/
- http://www.mikeware.demon.co.uk/index.html