What is the nature of the first impressions that form the basis for a film?

A film is the finished product. The basis of a film is laid on split second impressions that disappear as soon as they come. This means that the birth of a film can be a from anything as small as a note of music to an actor who seems to have been born for a role yet to be played. It isn't the story that takes the shape of a film. It is an idea, a feeling, a reflex of a second that draws into a film if it I followed beautifully.