Film stock produce only a very slight chemical change, proportional to the amount of light absorbed by each crystal. This creates an invisible latent image in the emulsion, which can be chemically developed into a visible photograph. In addition to visible light, all films are sensitive to X-rays and high-energy particles. Most are at least slightly sensitive to invisible ultraviolet (UV) light. Some special-purpose films are sensitive into the infrared (IR) region of the spectrum. In black-and-white photographic film there is usually one layer of silver salts. When the exposed grains are developed, the silver salts are converted to metallic silver, which
The Invisible Man (1975 TV series) effect of his work is the ability to turn objects invisible, and tries to find medical applications for his invention. He discovers that objects that are made invisible reappear after a few hours, and on living test animals the collars they wear re-appear before the living cells themselves. Obsessed by his invention, Westin decides to become invisible himself, in part to prove that a human can survive the process, and also to test a serum he has developed to reverse the invisibility. He reveals the process to his boss, Walter Carlson (Jackie Cooper), who is initially unimpressed by what he