What is film grain?
A photograph may appear to be made up of smooth continuous tones but close examination of film or paper with a magnifying glass or microscope reveals a different story. The images on film and paper are recorded as tiny microscopic dots, dots scattered in a diffuse pattern across the emulsion surface. The larger the dot the darker it is, so many large dots indicates a dark area and smaller dots a light area. Unlike computer graphic pixels, film grain is not in a regular linear grid. A picture with pronounced grain at normal viewing distance is very grainy. Highly obvious grain can be caused by processing problems, or can be simply an inherent property of the film. Generally speaking, slow film (film which does not react rapidly to light) has finer grain than fast film (film which reacts rapidly to light) – see the section below on film speed. Enlarging a picture will also enlarge the grain. Sometimes visible film grain is considered an undesirable thing, and photographers go to great le
