1. A method of processing images to determine at least one signature of a film, comprising the steps of: selecting chronologically a series of images from the film; obtaining primary visual shifts as shifts of at least one descriptor of a physical property between consecutive images of the series; calculating secondary visual shifts as differences between said primary visual shifts; calculating tertiary visual shifts as differences between said secondary visual shifts; and determining a signature of the film as a mean value and a standard deviation of the primary, secondary, and tertiary visual shifts.