The Cabinet of Dr. Caligari a classic German expressionism silent film. The film is regarded as one of the most famous in the progression of the horror genre. This scene in particular shows the sleepwalker kidnapping a virgin. Being the expressionistic and horror film it was meant to be, the film definitely has significant lighting effects.
This photo makes use of chiaroscuro lighting and low key lighting to create contrast between the environment and the characters. The space and the occupancy of light is on the sleepwalking almost like a spotlight. This is to show the situation and how, at that moment, it is critical that he get away. The use of these lighting techniques and how it shows contrast, especially in horror films, is to show the mystery or perhaps the evil in characters. In this photo, the contrast is so strong between the sleepwalker and the virgin, showing how different and opposite the two beings are, almost light good from evil.