What is film grain?

Film grain refers to the visible texture or pattern that is present in the image captured on film. It is a result of the chemical and physical processes that occur when film is developed, and is influenced by factors such as film speed, exposure, and processing techniques. Film grain is often considered a desirable aesthetic quality in film photography, as it can add a sense of texture and depth to the image. However, too much grain can also result in a loss of image sharpness and clarity, and is often considered undesirable in digital photography. There are various techniques for reducing or manipulating film grain in post-processing, such as using noise reduction software or adjusting the levels of the image.