Set up your key light. Place the light 45 degrees above and to the side of the individual you are filming. At this point you will notice a shadow is created over the subject’s nose or neck. To remove these shadows you will use the fill light.
Set up your fill light in front of the subject and close to the camera’s lens. Use a soft light that is less brilliant than that of the key light. This will prevent secondary shadows.
Now separate your subject from the background by using the backlight. Place this light 45 degrees above the back of the head, so that it also hits the shoulders of the subject. Use less light for light color hair.
Adjust the light arrangement to high key versus low key lighting. Carefully bring the intensity of the fill light close to the brightness of the key light. This will reduce contrast.
Adjust the light for dramatic scenes as needed. You do this by reducing the high key lighting to a low key lighting. To reduce to a low key lighting, reduce the fill lighting enough to allow the key lighting to dominate the scene. This arrangement is useful for dramatic scenes.
Control the quality of light by alternating between hard and soft light. If you want hard lighting, then you should use smaller lights that create strong edgy shadows. Use bigger lights to create soft light. You might also implement the use of light diffusion with large silk shades, which creates a more dramatic scene in film.