The emphasis in the drama lies on the spoken word, to which the stage manager does not add anything.

It is all contained in the lines.

In the photoplay the whole emphasis lies on the picture and its composition is left entirely to the producing artist.
But the scenario writer must not only have talent for dramatic invention and construction; he must be wide awake to the uniqueness of his task, that is, he must feel at every moment that he is writing for the screen and not for the stage or for a book.

And this brings us back to our central argument.

He must understand that the photoplay is not a photographed drama, but that it is controlled by psychological conditions of its own.