A developing agent is a chemical, usually phenidone, hydroquinone or metole, which reduces exposed silver ions to atomic silver to visualize an image on a film.

See also X-Ray Film, Film Processor, Activator, Clearing Agent, Developer and Fixer.

The company is developing and making specialized medicines for treating multiple sclerosis, dermatological disorders, female health concerns, cancer and is creating new diagnostic imaging techniques. Berlex, Inc. is a pioneer in the imaging market. It has introduced a broad range of imaging agents. Its contribution began in 1988 with the introduction of the world's first magnetic resonance imaging agent, Magnevist® (gadopentetate dimeglumine) injection. Berlex is headquartered in New Jersey and the U.S. affiliate of Bayer Schering Pharma AG, Germany.