Final answer:
Thin film interference refers to the pattern created when light is reflected and refracted within a thin film, potentially causing a phase change and interference.
Step-by-step explanation:
The term that refers to light being reflected from one intensifying screen, through the film, to the opposite emulsion and intensifying screen, is known as thin film interference. This phenomenon occurs when light striking a thin film is partially reflected and partially refracted. The rays that emerge after reflecting off the top and bottom surfaces of the film interfere with each other. This interference is dependent on the thickness of the film and the indices of refraction of the materials involved. When light reflects from a denser medium to a less dense medium, it can undergo a phase change, which affects the interference pattern, potentially producing constructive or destructive interference.