This technology corresponds to classical photography. In a film camera using the gelatin-silver process, light falling upon photographic emulsions containing chemical mineral compunds is recorded as a underlying image.
The latent image is subjected to photographic processing, which makes it visible and insensitive to light. The exposed film and accordingly the developing process reveals contrasting Negative and Positive, Reverse film stock and the film developing process. There is black and white film stock. In both categories, the sensitivity to light and film speed is differentiated (ASA/DIN).