Final answer:
Film with a double emulsion is used to enhance contrast because it increases the film's capacity to differentiate between light and dark areas, thus improving the image quality.
Step-by-step explanation:
The subject of this question is Photography, specific to the characteristics and functions of photographic film. Film is made with a double emulsion to enhance contrast. By using a double layer of emulsion, more silver halide crystals are present, which can be exposed by radiation (light). This increases the film’s ability to differentiate between lighter and darker areas of an image, thus enhancing the contrast. Advanced photographic technologies like the Kodachrome and Agfacolor Neu film utilized multilayer emulsion principles for color reproduction, but the primary purpose of a double emulsion is to increase contrast, not color reproduction, speed, or durability.