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.