There are two retail methods for photo processing – "wet" technology and "dry" technology. Wet technology involves developing film in wet chemicals, printing the image on photo paper, and then developing the paper in wet chemicals to finish the product. Newer dry technology does not involve developer or fixer chemicals. Pictures are printed on paper using inkjet printers or thermal transfer to paper. Most retail outlets use dry technology minilab photo processing.
Photo-processing can produce silver-bearing or other waste streams that may be regulated as hazardous wastes. Chemicals used in photo processing such as developer solutions, stop baths, fixers, intensifiers, and color processing material may be hazardous wastes. In addition, older photo processing solutions, spent rinse water, scrap film, and scrap printing paper contain varying concentrations of silver, some of which may be RCRA regulated hazardous wastes. If such wastes are sent for recovery of silver (i.e., recovery of economically significant amounts of precious metals), then reduced standards for the generators, transporters, and persons who store these materials will apply.
EPA's RCRA in Focus guidance has information on using, recycling,and disposing of photo-processing chemicals, and the CRC Hazardous Waste page provides more detail on hazardous waste requirements. Specific properties associated with photo-processing chemicals are generally listed on Safety Data Sheets provided by chemical vendors.
Discharges to the sewer system of wastewater from wet photo processing are restricted at the local wastewater utility or publicly owned treatment works (POTWs) level. Many POTWs have specific effluent limits for discharges of silver from photo processing and may require a pre-treatment permit, registration, or compliance with special procedures and reporting. Photo processing wastewater from retail facilities not served by municipal sewer must be hauled off site for treatment and disposal, and may be subject to proper management as a RCRA regulated hazardous waste.
Emergency Planning and Community Right-to-Know Act (EPCRA) regulations establish reporting obligations for facilities that use or store certain chemicals. Some photo processing chemicals, such as ammonia, formaldehyde, hydroquinone, and nitric acid, are considered "extremely hazardous substances" and subject to reporting obligations under federal EPCRA regulations and similar state requirements.
Dry photo processing technology may significantly reduce issues related to toxic chemicals, wastewater effluent, and hazardous waste. In addition, these systems generally use less energy than the traditional wet processing. Used ink or toner cartridges may need to be properly handled as wastes, depending in part on whether (as is often the case), they may be recycled or sent back to the manufacturer for refurbishing. Other waste streams from dry photo processing may include materials used to clean or maintain equipment or removed from waste ink/toner collection units inside the photo processing equipment. There are some other environmental impacts as the photo processing units may produce ozone depleting gases and volatile organic compounds (VOCs).
For stores using wet technology, switching to photo processing products and solutions that are biodegradable can reduce the burden and cost of handling hazardous waste. There are also management practices that can help reduce the amount of chemicals used. EPA's RCRA in Focus has information on how to reduce the chemicals used and waste generated during photo processing.
Paper use is one of the most significant environmental impacts for any printing process. Management approaches to reduce mistakes and therefore paper use, as well as recycling waste paper will reduce the environmental impacts of photo processing.
Not all paper is equal. Paper that is Forest Stewardship Council (FSC) certified, has recycled content, is unbleached or made with more environmentally friendly manufacturing can all significantly reduce environmental impacts. There are many resources for evaluating paper and most manufacturers offer environmentally preferable products. Conservatree has information on paper and lists of products for buyers. The Environmental Paper Network has an EcoPaper Toolkit for purchasers as well as the Paper Calculator for estimating the environmental footprint of paper.
National Association of Photographic Manufacturers, Code of Management Practice for Silver Dischargers