On what makes a film adaptation of a play succeed or fail on its own terms.

Plays and films share dialogue but differ in everything else. The stage creates meaning through the physical relationship of actors in a shared space with an audience that is also physically present. Cinema creates meaning through the camera's relationship to its subjects: what it shows, what it excludes, how it moves.

The failure mode for adapted plays is the photographed stage: a film that preserves the theatrical conventions — the limited locations, the verbal density, the theatrical staging — without finding cinematic equivalents for their effects.

The success mode is transformation: finding what the play is doing that a stage cannot fully achieve and using the camera to do that thing.

Lumet's 12 Angry Men works because the camera can create spatial pressure by getting closer and closer as the film progresses: the jury room shrinks across the film's duration in a way a stage cannot achieve. Polanski's Carnage works because the camera can catch the micro-expressions of discomfort and contempt that the audience in a theater cannot see. Both are using what theater cannot do.