About Film Grain

The physical structure of film is a flexible support coated with emulsions of gelatine and light-sensitive silver halides. The silver halide crystals vary in size, shape, and sensitivity, and are randomly distributed within the emulsion. These crystals form clumps which are visible as grain.

Fast films have a greater proportion of large crystals which form larger clumps, therefore appearing grainier.

In areas of the image with less exposure, the largest crystals respond to the light, so shadow areas of negative contain the most grain. In well-exposed negative, these areas print very dark and the eye cannot distinguish the grain. Midtone regions will display the most apparent graininess.

combustion includes two operators that manage grain in clips. It is possible to add grain to or remove grain from the RGB channels in any image using the Add Grain and Remove Grain operators.

Grain in an image can be either beneficial or detrimental to your clips. In the background of an image, graininess can make it difficult to pull a clean and effective key. As an added effect, graininess can be effective in synthesizing a film quality in a video image.