The Swedish film censors required numerous cuts in the film, before authorizing its release. Among the censored scenes were the closeup of the finger being removed from the hanged man's hand, the trampling of the cross in the witch's sabbath scene, the shot of the oozing infant held over a cooking pot, a closeup of a woman's face while she is on a torture rack, closeups of several instruments of torture being employed, and a shot of a demon embracing a nude woman (all these shots have since been restored to the film).
Director Benjamin Christensen originally planned to write the script with the help of historical experts, but that plan fell through after he discovered that most of the experts he had in mind were against the making of the film.
Maria, the weaver (one of the persecuted witches) was played by Maren Pedersen, who Christensen allegedly discovered while she was selling flowers on a street corner. Pedersen claimed that she was the first Red Cross nurse in Denmark. During the shoot, Pedersen reportedly turned to Christensen and said, "The Devil is real. I have seen him sitting at my bedside." Christensen was so struck by this confession of modern demonic activity (or at least the belief in modern demonic activity) that he incorporated this anecdote into the film itself.
Even though most scenes were filmed in interior studios, because Benjamin Christensen felt that the actor's performances would be best influenced by a more dark and ominous atmosphere, most of the film was shot at night, almost unheard-of at the time.
To achieve the scene in which the witches are flying over the roofs of the town, Benjamin Christensen and his cameraman Johan Ankerstjerne photographed a miniature town (with each house about 2 meters in height) on an enormous turntable, which operated manually and took the strength of 20 men to operate. Then, several costumed actors were photographed on broomsticks against a black background. To make the heavy costumes ripple in the "wind" Christiansen brought in an airplane motor. A total of 75 witches were photographed, each individually, and a special optical printer was built by Ankerstjerne to put them together (only about three of four appear on the screen at one time). The construction of a model town was decided upon after test footage proved the original idea of shooting from a movie train was a bad one, as too many modern structures, not to mention telephone poles and wires, were unavoidable. The test footage survives and is superimposed with Christiansen seated in a chair, acting out the part of a witch.
To get dramatic skies for the scenes where actors are shown outside, in silhouette, Benjamin Christensen dispatched a cameraman to Norway to photograph the dramatic, cloudy skyscapes that appear in the finished product.
The failure of the original copyright holder to renew the film's copyright resulted in it falling into public domain, meaning that virtually anyone could duplicate and sell a VHS/DVD copy of the film. Therefore, many of the versions of this film available on the market are either severely (and usually badly) edited and/or of extremely poor quality, having been duped from second- or third-generation (or more) copies of the film.