The part of Lisa Schindler was written for Marlene Dietrich. Producers vetoed the choice, and Simone Signoret was cast.
According to Writer and Director Curtis Harrington, the credited Set Decorator, provided by the studio, proved unusable, so he was given a paid vacation during the production. Costume Designer Morton Haack did the set decoration, but because this was against union rules, he was not credited for his work.
Originally budgeted at $1M, director Curtis Harrington brought the film's negative cost in at $450,000.
The electrical device in the couple's collection of art that makes a bolt of electricity that travels up inside a "V" shaped wire appears to be inspired by the Ken Strickfaden props from Frankenstein (1931) and its sequels. Also, a character watches a scene from Drácula (1931) on TV (with music not in the actual film).