It was also found that, when developer solution is optimally formulated, the maximum photographic speed is rather insensitive to the choice of developing agent ( James 1945 ), and there exists a limit for the size of silver cluster that can be developed.
22.
Sulfite in a developer not only acts to prevent aerial oxidation of the developing agents in solution, it also facilitates the regeneration of metol by hydroquinone ( reducing compensation and adjacency effects ) and in high enough concentrations acts as a silver halide solvent.
23.
The'magic'of the cards were the fact that they came out of the pack blank until the image was revealed by moistening the surface and applying the developing agent which was supplied by the wrapper in a one cent pack or a piece of orange mystery paper supplied in the five cent packs.
24.
Therefore, it is very important for the chemical reduction potential of the developer " solution " ( not the standard reduction potential of the developing agent ) to be somewhere higher than the Fermi energy level of small metallic silver clusters ( that is, the latent image ) but well below the conduction band of unexposed silver halide crystals.
25.
The " calotype ", or " talbotype ", was a " developing out " process, Talbot's improvement of his earlier photogenic drawing process by the use of a different silver salt ( silver iodide instead of silver chloride ) and a developing agent ( gallic acid and silver nitrate ) to bring out an invisibly slight " latent " image on the exposed paper.
