NEGATIVE

photographic image that reproduces the bright portions of the photographed subject as dark and the dark parts as light areas. Negatives are usually formed on a transparent material, such as plastic or glass. Exposure of sensitized paper through the negative, done either by placing the negative and paper in close contact or by projecting the negative image onto the paper, reverses these tones and produces a positive photographic print. Black-and-white negatives consist of grains of metallic silver chemically reduced during the development process from silver salts struck by light during exposure. Colour negatives consist of three tonally reversed dye images that are formed along with a silver image during development. Chemical removal of the silver images leaves the three insoluble dye images superimposed in register. Some modern black-and-white films also use insoluble dyes to form the negative image.