silver; the donation oxidizes the developer which then activates the dye couplers to form the colour dyes in each emulsion layer, but only does so in the dye couplers that are around unexposed silver halide.
# A rehalogenising bleach converts the developed metallic silver into silver halide.
# A fixer removes all silver halide by converting it into soluble silver complexes that are then washed away, leaving only the dyes.
# The film is washed, stabilised, dried and cut.

In the RA-4 process,