This document discusses codes and conventions in film genres. It defines codes as systems of signs that create meaning, which can be technical like camera work or symbolic by showing what is beneath the surface. Conventions are generally accepted ways of doing things within a genre. The document explains that codes and conventions are always used together, as discussing a technical code without how it is conventionally used in a genre provides incomplete information. It provides the example of lighting being a technical code used across genres, but horror conventions dictate side and back lighting to create mystery and suspense.