The black and white film and paper are processed similarly. The film and paper used for color photography consist of three separate layers of photosensitive emulsion with intermediate layers which are coated on clear film base or on paper. Each emulsion layer is sensitive to either red, green, or blue light due to the presence of selective dyes in the emulsion. The waste streams generated vary widely according to the type and volume of processing. Color processing usually represents the majority of operations and generates larger waste streams.
Wastes generated by photoprocessors are primarily aqueous effluents.
Source reduction is the most preferred method of waste minimization, followed by recycling and resource recovery. Source reduction methods include inventory control, producing only necessary amounts of processing solutions, preventing the loss of potency by using floating lids or balls on developer solutions, and improvements in quality control for all processes to reduce discharges. Contamination of process baths by chemical carry over can be reduced by the use of squeegees to remove the excess liquids from film and paper. Chemical waste may be reduced by precision monitoring and adding of chemical replenishment to the process baths. Material substitution involves using an alternative processing chemical for the one currently in use in order to reduce the quantity of waste generated or the hazardous characteristics of the waste.