The film was shot digitally, but director and editor Mike Flanagan, in order to add a retro feel to the film, added elements in post-production to give the appearance of a movie shot on film. Those include the 'cigarette burns', marks that appear every 20 minutes or so in the upper right corner of the frame, which were used to signal a change of reels for film projected.
EASTER EGG: The mirror from Oculus (2013), Mike Flanagan's previous film, can be seen in the basement corner.
To further add to the retro atmosphere director Mike Flanagan decided to use Universal Pictures 1963-90 title design by Universal Title and Optical for MCA Inc. to open and promote the film.
The house used in this film is the same house as it appears in another horror film, Cuando las luces se apagan (2016).
Director Mike Flanagan says he wanted to create the thriller as if it were shot in 1971. Some techniques included antique lenses, scene fades, and camera zooms instead of steadicams. Other simulated techniques: dust on the negative, subtle warping of the audio track, reel jumps and split-diopter (where both the foreground and background are in focus).