Fogging (photography) - Taxonomy of Fogging

Taxonomy of Fogging

One kind of fog is produced from a silver halide crystal having a fog centre created by various reactions. One obvious case is when the emulsion is inadvertently exposed to light. In this case, the fog centre is created as latent image and made into visible fog by the action of the developer. Another case is when the fog centre is created chemically, with propylene glycol and white wax.

There is another kind of chemical fog, broadly classified as silver stain. This kind of fog does not require a fog centre in each silver halide crystal, since they can grow on other substrates other than photosensitive silver halide crystals.