emulsion
n.n. a mixture of two liquids that usually do not mix, like oil and water. In photography, it refers to a thin layer of chemicals on film that reacts to light to create an image.
n. a mixture of two immiscible liquids, such as oil and water, in which one is dispersed in the other. In the context of photography, it refers to a suspension of silver halide crystals in a gelatin emulsion on photographic film.
The photographer used a high-speed emulsion to capture the fast-moving birds.
The quality of the final print depends largely on the sensitivity and grain structure of the film emulsion.
Early photographers struggled to stabilize the emulsion on glass plates, leading to the eventual development of more durable celluloid-based films that could withstand the rigors of transportation and storage.
Borrowed from French émulsion, from New Latin ēmulsiō, ēmulsiōnis, based on Latin ēmulgeō (“I milk out, extract”).