In The Lords of Salem, Zombie uses practical lighting to create a supernatural feeling in simple shots. Through out the film there are multiple lamps in nearly every shot, and all of them have a blown out effect, contrasting their brightness with the dreariness of the scenery. The lights symbolize a the supernatural, surrounding all the characters through out the film. In this shot of the hallway the furthest light swings from side to side inexplicably, further illustrating the lights as a key component to the supernatural world.
In these two shots, Zombie uses the lights to connect the characters of Lacy Doyle(Judy Geeson) and Heidi(Sherri Moon-Zombie). Their relationship on the surface is that of landlady and tenant. When they go their separate ways, Lacy makes her way up the stairs surrounded by three lights.
Zombie cuts from this shot to the following of Heidi walking outside, also surrounded by glowing lights. This visual queue shows that these characters will be more connected than their relationship would lead you to believe - which is bad news for Heidi.
Beyond the general practical lighting, Zombie also makes strong use of the color red to signify the fantastical. The first moment in which Heidi experiences something otherworldly is during her night with Whitey(Jeff Daniel Phillips). Here he's dancing to Venus in Furs by The Velvet Underground. Here we can see two practical lights that we perceive as giving off the primary light of the room. But we can see the ceiling lights in the background and a lamp on the far left that are shaded in red.
When they put on The Lords record, the white lights are seemingly overtaken by the red ones. Notice that the camera has now moved further down than in the previous shot and tilted upward - showing more of the red ceiling lights than before.
The camera tracks from right to left, as Heidi moves further from Whitey. Eventually the red lamp eclipses the white bulb:
We then cut a close up of Heidi as she seemingly experiences a flashback involving the witches persecuted by Jonathan Hawthorne.
This use of red continues through out the film, like when Heidi first enters Apartment #5 the room is lit by a red cross.
After this Zombie becomes more somewhat more subversive with his use of red, as the superantual world bleeds into Heidi's normal life. For example, Megan(Patricia Quinn) , the most abrasive of witches has red hair. In the scene where she dreams of being raped by the priest, the red returns as a part of the walls in the background and the drapes.
The red is also used when the Lacy, Megan and Sonny(Dee Wallace) reveal their true nature by killing Francis Matthias(Bruce Davison). When we were in Lacy's apartment previously, the color scheme was closer to green.
It's when Heidi eventually succumbs to her addiction she makes her way to her dealer, who has a bright red door. This moment is pivotal to the film because it's Heidi who is comes to the color, and it's after this moment, where she fully succumbs to the will of her tormentors.
The skulls on the door become her mask once she starts smoking heroin again and gives herself to Satan in Apartment #5.
This all leads to Heidi giving birth as the witches rub the blood from her womb all over her body. The color red has washed over her body and she realizes her destiny as the mother of Stan's child. Congratulations Heidi.