NOT a film noir
Just to clarify: this is definitely not a film noir, according to the definition of the film noir genre. It is clearly a "thriller" a la Rebecca, Gaslight and Notorious (none of them are film noir). The fact that Fox markets it as a film noir is obviously a marketing gimmick. Here are some examples why it is not a film noir (not in any particular order):
- hardly and use of chiaroscuro light (harsh light/dark contrasts)
- hardly any night scene and the lighting is fairly high-key
- no flashbacks
- very little subjective storytelling (we only hear her mental voice-over twice, and it is only for exposition, not to describe a psychological state)
- the narrative is plot, rather than character-driven
- the main character's morale is not ambiguous, nor twisted (she is a heroin, not an anti-heroin; true, she forged her identity, but a) it is not an important plot point b) it does not make us like her less and c) she admits it to redeem herself)
So, Film Noir is quite an elusive genre, and it is not always easy to identify one (e.g. Last Weekend). Story elements and style play an important role. However, it is easy to recognise a film that is definitely not Film Noir, especially since it has the clear elements of a thriller.
It is still a great film, though. Excellent acting.