The standard way to process color
photographic film (in the US, at least - the photo shop here wouldn't touch a roll I got in
Germany because it didn't say C-41 on it, though it was exactly the same film). The
exposed film, containing three layers (
RGB) of
silver halide crystals &
color couplers, is
developed, reducing the silver halide crystals that have been exposed to light to
metallic silver. During this process, the surrounding color couplers are transformed into
dye (of a color opposite that of their layer, ie
CMY).
Bleach is then used to change the silver into a form which is then dissolved by the
fixer. Finally, the film is rinsed to remove all traces of the silver and you have a
negative.