Three-point lighting is the basic setup for lighting cinematic subjects and involves the use of a key light, a fill light and a back light. The key light is usually the brightest of the three lights and is used to illuminate the face of the subject that the camera is pointing at. As the key light cannot occupy the same space as the camera, it is usually placed to one side of the camera, hitting the subject at an angle. This means that one side of the subject gets more light than the other. To ensure that this other side is not cast in unnatural shadow, a fill light is used and is placed on the other side of the camera. Fill lighting is less intense than key lighting, so the subject does not appear harsh and flat.
Finally, a back light is placed behind the subject, often at an angle diagonally opposite to the fill light. The back light uses soft light behind the subject, which softens the harsh edges created by the key light and the fill light. This makes the subject look more realistic and three-dimensional.
Key lights should be placed to the side of the subject where natural illumination is seen to be coming from. For example, if the subject is standing in a room with one window, the key light should be placed on the same side of the subject as the window.
Film noir is a style of film dealing with dark, fatalistic stories usually involving urban crime or corruption. Famous noir classics include "The Big Sleep" and "Double Indemnity." Film noir is usually shot in black and white, as this best suits the sinister mood of the subject matter. The mood is accentuated by utilizing harsh, single-point lighting (using only one source of light) to create deep black shadows, and a focus on a single area of the frame, such as one side of a character's face. Often, a single light with a narrow beam of focus will illuminate a single side of a sinister character's face.
The best effects are achieved by placing the light higher than the character's face and placing the camera lower so the character seems to be looming over the audience. Little or no fill lighting is used, so the narrow portion of the frame that the light hits stands out in contrast to everything else. Areas immediately adjacent to where the light hits are thrown into deep black shadow.
Outdoor shoots have the same lighting requirements as indoor shoots, so the goal is often to achieve outdoors what was achieved indoors using a basic three-point lighting setup. Outdoors, on a sunny day, the key light is the sun. The problem is that you cannot control the brightness of the sun or its position.
But you can manage the way that your subject is lit by utilizing the sun. Place a reflector low down to the subject, reflecting sunlight back up onto the subject. This reflected light acts as a fill light. Reflected fill lighting is softer than original sunlight and removes harsh contrasting shadows while giving three-dimensional depth. If the natural sunlight is too harsh, you can place filters or diffusers made of gauze between the sun and the subject being filmed. This softens the light hitting the subject, and you can still use a reflector as a key light. The reflector can be positioned to utilize direct sunlight or diffused sunlight, depending on how much fill light you choose to use.