In photography, contamination refers to the presence of unwanted chemical traces in areas where they should not be, such as on film, paper, or in developing solutions. Contamination can affect image quality, causing discoloration, uneven development, or staining, and may result from improper handling, dirty equipment, or mixing chemicals incorrectly. Darkroom photographers and lab technicians carefully manage workspace cleanliness, chemical storage, and handling procedures to prevent contamination and ensure consistent, high-quality photographic results.