What ideas or concepts was Elia Kazan trying to accentuate when he made the decision to film On the Waterfront in black and white and how did this decision influence viewers interpretation of the text?
Like music in a film, color can enhance the mood and work as a dramatic factor. However, if it is not necessary, it can distract movie viewers from focuses upon what directors want them to see. Roger Deacons, cameraman and director of photography for such films as Oh Brother, Where Art Thou (2000, US) and The Hudsucker Proxy (1994, US) made this observation,
It's vitally important to be able to separate shapes and surfaces through the use of light and shade, and to focus the audience's attention on what you want them to see.
[Black-and-white] focuses you on the content and the story, and it really concentrates your attention on what's in the frame.
Eliz Kazan's masterpiece, On the Waterfront is perfectly suited to black-and-white film because the focus of this intense drama is primarily upon characterization--the interaction of characters and the external and internal conflicts of these characters. With black-and-white flim, there can be the single focus on characters' faces while the setting fades into shadow; this condition increases the intensity of the dialogues and the facial expressions of the actors. Indeed, the use of black and white affords a depth of light and dark that cannot be produced with the distraction of colors which absorb light differently, confusing the intended effect.
Much like film noir, which derived from German Expressionism, significant scenes from On the Waterfront make use of shadows and distorted lighting for effect. One technique, for instance, uses light shone from below to make a face seem ominous.The famous scene in the backseat of a car with Terry and his mobster brother, Charley "the Gent" Malloy, makes use of side light to reflect character ambivalence in Charley while the changing light from the back window enhances the range of emotions expressed by Terry.
There is little doubt that the employment of black-and-white film which allowed Kazan subtle and direct control with its focus and simplicity leaves a distinct and intense impression upon the viewers of his film as they recall mainly the faces of the actors and the expressions of fear, conflict, love, and hate that are intensified by the sharp use of light and shadows that only such film affords.