valokuvafilmin

Valokuvafilmi, often referred to as photographic film or simply film, is a transparent strip or sheet material coated on one side with a gelatin emulsion containing light-sensitive silver halide crystals. When exposed to light, these crystals undergo a chemical change, forming a latent image that can then be developed into a visible photograph. The process relies on the principle of photochemistry, where light energy triggers a reaction within the silver halide.

The film base, typically made of cellulose acetate or polyester, provides a stable support for the emulsion. The thickness of the emulsion layer and the size and sensitivity of the silver halide grains determine the film's resolution, contrast, and speed (ISO rating). Different types of film exist, including black-and-white film, which records tonal variations, and color film, which uses multiple layers of emulsion sensitive to different colors of light to reproduce a full-color image.

Historically, film was the primary medium for capturing images before the widespread adoption of digital photography. Its use in cameras, projectors, and scientific instruments was extensive. While digital technology has largely replaced film in many applications, it remains popular among enthusiasts and professionals for its unique aesthetic qualities and the tactile experience of shooting and developing. The careful manipulation of film and processing techniques can yield distinct visual characteristics not always easily replicated digitally.