The directing team claims that their previous movie "La Pasajera" was like a Blumhouse film, while "Viejos" is more like an A24 movie.
Cinematographer Ignacio Aguilar, in his second feature film with González Gómez & Cerezo, deliberately avoided cool tones for the most part, in order to suggest an increasing extreme heat wave over Madrid. The filmmakers also wanted to make this film as visually different as possible to their previous feature, "La Pasajera", which had a very 1980's sci-fi color palette dominated by intense blue hues at night. The color palette for "The Elderly" originally came from Spanish painter Francisco de Goya's "black paintings", so the filmmakers decided to work with different degrees of browns, yellow-ambars, grays and some reds.
Second collaboration between Raúl Cerezo and Fernando González Gómez after "La Pasajera" ("The Passenger", 2021), which also starred Paula Gallego. Many members of the crew worked on both films.
Director Raúl Cerezo first wrote the story as a short film in 2013, but quickly dropped the idea and decided to make it as a full length feature film. Javier Trigales wrote several drafts of the movie and the screenplay was later revised, until principal photography was about to begin, by Rubén Sánchez Trigos.