Even the best and most famous production designers are constrained by the collaborative work environment of the typical movie production. While charged with creating the physical world for a movie, the designer usually has little control over how the design is lit or photographed, or how actors will be positioned in relation to his or her sets. The look of a film is really achieved in collaboration at least with the director of photography (DP), who in turn answers to the same master, the director.
At the simplest level, this collaboration dictates how much of an environment the designer has to create. In a brute, literal sense, a production design always ends exactly at the edge of the frame. Thus the designer must have a sense of how much of a set or location a director or DP wants to show, which in turn is determined by the photographic process (academy ratio vs. widescreen, or anamorphic widescreen vs. matted) and lens choice (does the director prefer wide angles, or have a fondness for close-ups?)
Also, different film stocks may have particular sensitivities that discourage the use of colors in a given range, or be particularly poor in resolving objects in shadow. At a more sophisticated level, the designer has to consider technical issues, such as whether or not the DP wants some kind of "practical" (i.e., visible) lamps on the set to serve as the (illusory) lighting source. Will the characters enter a dark room at night and turn on the light that will become the "key light" (primary illumination) for the scene? If so, the production designer will not only have to find or make a lamp that fits into the design concept, he or she will also have to be certain that its placement will not interfere with the lights on the set that are the true illumination.
Similarly, when working with a director who plans to use a lot of camera movement, the designer and DP must be certain that some walls can be rolled out of the way quickly to accommodate the camera crew as it moves with the action, that there is sufficient space for the camera and crew regardless of where the camera is pointed and where it is moving, and so on. Sufficient space for camera and crew is one of the major considerations in deciding whether or not to use a sound stage. If the director insists on elaborate camerawork, and a location set cannot accommodate camera and crew, a sound stage is a must.
Beyond such technical considerations, there is the subtle, ineffable, but necessary question of what simply feels "right" for a particular design. While designers may have a lot of say in creating or finding these details, it is ultimately the director who decides what is included or excluded from the frame. And because it is ultimately the director who makes such decisions, it is also ultimately the director, not the designer, who determines the final visual style of a project.
