Janowitz suggested that the settings for CALIGARI be designed by the painter and illustrator Alfred Kubin, who, a forerunner of the surrealists, made eerie phantoms invade harmless scenery and visions of torture emerge from the subconscious.
Wiene took to the  idea of painted canvases, but preferred to Kubin three expressionist artists: Hermann Warm, Walter Rohrig and Walter Reimann. They were affiliated with the Berlin Sturm group, which, through Herwarth Walden’s magazine Sturm, promoted expressionism in every field of art.
Although expressionist painting and literature had evolved years before the war, they acquired a public only after 1918. In this respect the case of Germany somewhat resembled that of Soviet Russia where, during the short period of war communism, diverse currents of abstract art enjoyed a veritable heyday. To a revolutionized people expressionism seemed to combine the denial of bourgeois traditions with faith in man’s power freely to shape society and nature. On account of such virtues it may have cast a spell over many Germans upset by the breakdown of their universe.
“Films must be drawings brought to life”: this was Hermann Warm’s formula at the time that he and his two fellow designers were constructing the CALIGARI world.
In accordance with his beliefs, the canvases and draperies of CALIGARI abounded in complexes of  jagged, sharp-pointed forms strongly reminiscent of gothic patterns. Products of a style which by then had become almost a mannerism, these complexes suggested houses, walls, landscapes. Except for a few slips or concessions — some backgrounds opposed the pictorial convention in too direct a manner, while others all but preserved them — the settings amounted to a perfect transformation of material objects into emotional ornaments. With its oblique chimneys on pell-mell roofs, its windows in the form of arrows or kites and its treelike arabesques that were threats rather than trees, Holstenwall resembled those visions of unheard-of cities which the painter Lyonel Feininger evoked through his edgy, crystalline compositions.