A child doesn't have to be a prodigy. The only thing that matters is that he should't become 'stuck' in childishness - Andrei Tarkovsky

No one component of a film can have any meaning in isolation: it is the film that is the work of art. And we can only talk about its components rather arbitrarily, dividing it up artificially or the sake of theoretical discussion.

Si alguien intenta llegar a ser director de cine, está arriesgando su vida entera, y él es el único responsable de ese riesgo

What is the essence of the director's work? We could define it as sculpting in time. Just as a sculptor takes a lump of marble, and, inwardly conscious of the features of his finished piece, removes everything that is not a part of it — so the film-maker, from a 'lump of time' made up of an enormous, solid cluster of living facts, cuts off and discards whatever he does not need, leaving only what is to be an element of the finished film, what will prove to be integral to the cinematic image.