Giallo (gee-ah-low, which I affectionately pronounce as "jello"), the Italian word for "yellow", was named "because of thriller novels [known as Il Giallo Mondadori] which were distributed in the 1920s-1950s and marked by their bright yellow pages" (Wilhelmi, 2020).
Giallo films are usually murder mysteries or horror thrillers. English-speaking audiences have used the term giallo to refer specifically to a genre of Italian-produced thriller-horror films known to Italian audiences as giallo all'italiana. At the end of the day, a Giallo is more than just being an Italian horror film, a Giallo is a vibe.
Common themes are social commentary, sex, mental illness, fetishism, bloody violence, bright colors, and brutal crimes. These films are traditionally gritty, gaudy, and bold. Some notables are Tenebrae (1982), Suspiria (1977), and Deep Red (1975). Dario Argento is said to be the king of Italian Horror, and he directed all three of the previous movies mentioned.
Historically speaking, Giallo films started dropping in the 1960s. Many believe the first to be Mario Bava’s 1963 film The Girl Who Knew Too Much (Kench, 2021).
Let's look at a few examples of the common themes.
1. Style and Music Emphasis
Suspiria (1977) stands the test of time. Nearly 50 years later and this is still terrifying due to the cinematography, striking colors and themes, and eerie soundscape. The aural and visual stimuli are haunting and tense.
2. Bloody Violence
Tenebrae (1982) is a gem that masters the first person POV violent murders.
3. Female Protagonists and Victims
The Girl Who Knew Too Much (1963), potentially the first official giallo, featuring final girl Nora.
“I love women, so I would rather see a beautiful woman killed than an ugly man." - Dario Argento (Ricciuto, 2018).
4. POV Murders & Black Gloves
Deep Red (1975) - fun fact: all of the kills in this movie were done by Dario Argento himself.
5. Fetish
Giallo movies tend to fetishize, well, everything. Check out this dope trailer for Blood and Black Lace (1964).
References
Riccuito, D. C. (2018, August 21). Design for killing: Function follows form into the megalomania of giallo. Bright Lights Film Journal. https://brightlightsfilm.com/design-killing-giallo-bava-argento-blood-fetish/#footnote_0_28219
Kench, S. (2021, October 25). Giallo films explained - argento, bava & beyond. StudioBinder. https://www.studiobinder.com/blog/giallo-films-definition/
Wilhelmi, J. (2020, April 2). Giallo explained: A history of the Italian horror movies. ScreenRant. https://screenrant.com/giallo-explained-italian-horror-movie-history/