Unfortunately, the thiosulfate component of the fixing bath can have a long-term adverse effect on the processed film and, therefore, must be thoroughly washed from the emulsion during the final wash cycle.
Provided that they do not contain any metal complexes, basic inorganic liquids (including developer, fixing baths, soap solutions, surfactants, wash water) are routed to a continuous-flow neutralization system operated with waste acid, milk of lime and FeC13.