Tropes of The Noir Genre

When we decided to make our film a Neo-Noir we thought we would first investigate some common features and conventions commonly seen in this type of film.
Noirs are mostly crime/mystery dramas. 1940-50 was the classical ''golden age'' of these films. Classics include double indeminity, touch of evil and the big sleep.
Noir is visually darker than average gangster/crime films making effect use of light and long shadows instead of bright and clear camera work. Camera angles can be unsual/creative giving the audience a sense of mystery and unease. 

The plot is usually a blend of complex storytelling/characters and pulp fiction narratives.Common storylines of noir films are heists, muder mysteries and innocent men or women accused of a crime they didnt commit. There is usually a skewed timeline of events with flashbacks, flashforwards and misleading narration(eg usual suspects). 
The main characters motivations can be pyschologic or even a personal vendetta like the original scarface. Usual characters include a dectective, the 'femme fetal' character, gangsters and corrupt police.
                                                           
                             Femmel fetal Carol Balawyder

                          
              Classic bad cop Hank Quinlann(from Touch of Evil)

Melancholic Jazz music is usually the soundtrack for noir films with songs featuring saxophone, minor piano chords, chello hits, symbol rattling and muted trumpets. The soundtrack can give the film a tone of mystery and a feeling of class/sophistication.
Below is from the neo noir film taxi driver and is a classic exmpale of the jazz found in these types of films. 



For the cinematopgraphy of Noir films there are conventions which are also followed. 
A characters face can be obscured and concealed for the opening shots of the film or if he has just commited a crime.

 Dutch and canted angles are often used to make the viewer feel uneasy and give the scene a skewed perspective.

The setting of a Noir is usually in a dark 'villianous' city that shows signs of urban decay. The crime rate is high and the streets are filled with despair. Familiar settings include casinos and gamblign dens, nightclubs filled with seedy individuals, warehouses, docks, police stations, train staions and strip clubs.

Costumes for Noir films for male include trench coats, fedoras/trillbys, cigarettes, fancy shoes, shirts with overalls and fancy ties.
For females its usually red lipstick, fishnets, dark overcoats and short waitress like skirts.