Sheet Film
With 35mm film and 120 film there is information about the film on the film cassette or roll and in most cases pre-exposed onto the film by the manufacturer that develops up during the processing. Typically this information might include the manufacturer, the type of film, ASA and frame numbers, etc.
With Sheet film there is no information pre-exposed onto the film and the only way the type of film and ASA can be identified is through notch patterns which are a series of small notches cut into tone corner of the film. The notch pattern also identifies the emulsion side of the film when loading the film into the cut film holder the dark.
