The weather report playing on the television while Lavinia is washing dishes mentions Arkham, along with Innsmouth, Dunwich, and Kingsport. All these settings are part of different H.P. Lovecraft stories. In addition, Lavinia questions Benny about a former girlfriend from Aylesbury. It's another location that too belongs to Lovecraft's universe.
In a Q&A with Richard Stanley, he claimed that the film would be the first of a trilogy, with a Dunwich Horror adaptation coming next. Nevertheless, in March 2021 the trilogy was canceled after Stanley was accused of domestic abuse by his former partner Scarlett Amaris, and production company SpectreVision cut all relation with him.
The color used in this film to represent The Color is magenta, which doesn't exist as single wavelength of light as part of the spectrum of visible light (red, orange, yellow, green, blue, indigo, and violet; also known as "Roygbiv" to join the seven initials). Rather, it is an extraspectral color, that is only perceived by humans in a specific interaction of the optical rods in the eyes that detect red and blue in specific circumstances to create the magenta in the mind. Since red and blue are associated to evil and good, it means that The Color is apart from evil and good to come from another universe where these concepts cannot be applied. The color code for magenta is: RGB (Red-Green-Blue) 255, 100, 100; HSB (Hue-Saturation-Brightness) 255, 0, 255. The election of magenta to represent The Color is a hint for the previous The Color Out of Space (2010), a black and white movie where (at around 1h) The Color appears as little magenta bubbles and (at around 1h 11 mins) as uncountable magenta bubbles fusing to form The Color.
The narrator's name is Ward Phillips. (Ho)ward Phillips Lovecraft is H.P. Lovecraft's full name. One Lovecraft story from 1927 is titled The Case of Charles Dexter Ward, and features a character named Ezra.
Nicolas Cage always wanted to make a Lovecraft adaptation as tribute to his father August Coppola (Francis Ford Coppola's older brother) who was a big fan of H.P. Lovecraft.