Technical peculiarities betray peculiarities of meaning. In CALIGARI methods begin to assert themselves which belong among the special properties of German film technique. CALIGARI initiates a long procession of 100 per cent studio-made films. Whereas, for instance, the Swedes at that time went to great pains to capture the actual appearance of a snowstorm or a wood, the German directors, at least until 1924, were so infatuated with indoor effects that they built up whole landscapes within the studio walls. They preferred the command of an artificial universe to dependence upon a haphazard outer world.
Their withdrawal into the studio was part of  the general retreat into a shell. Once the Germans had determined to seek shelter within the soul, they could not well allow the screen to explore that very reality which they abandoned. This explains the conspicuous role of architecture after CALIGARI — a role that has struck many an observer. “It is of the utmost importance,” Paul Rotha remarks in a survey of the postwar period, “to grasp the significant part played by the architect in the development of the German cinema.” How could it be otherwise? The architect’s facades and rooms were not merely backgrounds, but hieroglyphs. They expressed the structure of the soul in terms of space.
CALIGARl also mobilizes light. It is a lighting device which enables the spectators to watch the murder of Alan without seeing it; what they see, on the wall of the student’s attic, is the shadow of Cesare stabbing that of Alan. Such devices developed into a specialty of the German studios. Jean Cassou credits the Germans with having invented a “laboratory-made fairy illumination,” and Harry Alan Potamkin considers the handling of the light in the German film its “major contribution to the cinema.”