Billy Wilder hired veteran cinematographer John F. Seitz to film Double Indemnity, and together they produced a visual aesthetic that became a template for film noir style. In film noir, exterior scenes in daylight are kept to a bare minimum. Interior scenes are often filled with smoke and shadows, symbolizing the cloudy layers of deceit and secrecy that often accompany the interpersonal relationships between the characters. The majority of the film takes place during the night-time, a clear reference to the criminal underworld around which the film noir genre tends to revolve.
The decision to filter light sources through venetian blinds was an especially influential innovation, creating a visual effect that rendered the actors' faces as if trapped behind prison bars. This moody, expressionist lighting technique was copied by many other crime dramas to follow, because it so evocatively created an atmosphere of foreboding and unease. Light and shadow are afforded great symbolic significance not only in the frame but in the script—Walter asks Phyllis to leave the lights on in the penultimate scene, but she disobeys him and turns them off. The discrepancy between light and shadow models the rift of trust in their relationship, as well as the separation between disclosure and secrecy more generally in the film.
Wilder and Seitz also strategically filmed certain scenes in order to work around the demands of the Hays Office in toning down its controversial content. For example, the film does not show Walter actually killing Mr. Dietrichson, instead zooming in on Phyllis's steely face. Ironically, this decision is arguably more disturbing to the viewer, highlighting Phyllis's utter emotionlessness as her husband is brutally murdered beside her. Wilder and Seitz were also forced to film the corpse disposal scene from the waist-up, in order to avoid violating the Hays Code. Thus, the viewer must imagine the violence and depravity that takes place just outside the frame.