Regarded as a key figure in set design for expressionistic film, Warm also created groundbreaking sets for films such as 'Das Cabinet des Dr. Caligari' (Robert Wiene, 1919) and 'Die Spinnen [The Spiders]' (Fritz Lang, 1919-20).
Here are a couple of photos of the original set models for the film. There are many more fascinating photos of them here (click on the image that says SET MODELS).
These stills give an idea of how the minimalist set is used to create feeling of maximum intensity:
The film itself was lost for decades. A fire has destroyed the original negative and there were no extant copies. However, a full copy was discovered in the early '80s in a janitor's cupboard in a mental institute in Oslo.
As well as the stunning sets, the film itself is also characterised by intensely emotional acting by the lead, Renee Jeanne Falconetti. She suffered greatly during the shooting of the film, as Dreyer made her enact scenes dozens of times and suppress her feelings to create the emotional temperature he wanted on screen. The camera's focus on her face throughout the film reveals an amazing performance:
The film is extraordinary, and worth watching in full. Here's a few minutes of it: