system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What makes a film a "Film Noir"?

What are the "ingredients" please? Are there key themes? What are they?  Please ELI5 because I don't have the language to understand academics. Thank you!
gpt
Film Noir is an artistic movement. It started in the 1940s when screenplays inspired by American crime fiction were brought to the screen, primarily by European directors.

The films share a certain storytelling: highly stylized, overtly theatrical, with imagery from an earlier era of German “expressionism” (a movement that started before WWI that rejected realism).

To this day the debate goes on as to whether “noir” is a film genre defined by its content, or a style of storytelling or identified by its visual attributes.