I spent a couple days with some friends of mine working on lighting setups for interview situations. My friends are into movie making and anything to do with cameras and lenses is of interest to me. I wanted to take some time to write down some of the things I learned while playing the setups.
The first and most important observation was that the purpose of lighting is to bring out lines and features of a persons face. The key features of the face to look at when balancing the light are the nose, the jaw line, and the line that starts at the cheekbones and falls down to the chin, and also the brow and eye sockets. You want those lines to stand out distinctly. When those features aren’t noticeable, the face tends to look flat and sometimes fat.
To bring out those characteristics, you use shadow and highlight, placing lights at angles that will cast shadow to emphasize to hide features of the face. To do this, you will often use three basic kinds of lights.
The key light is the main light light source and is also used to determine which direction you want the shadows cast and to provide the point of light in the eyes that prevents them from looking dark or empty.
The fill lights only purpose is soften the shadows cast by the key light, and fill lighting can be accomplished more often easily by using a bounce card than another lamp.
The last light is the backlight, which is used to highlight the edges of the hair and shoulders, and sometimes to cast light onto the sides of the face to create a starker line on the cheekbones and temple.
Some other observations had to do with atmosphere. Darker lighting combined with soft lighting adds a feeling of closeness. A brighter more even lighting scheme indicates more distance. The color of light you choose helps convey emotion as well, the warmer tones are more intimate, cooler tones are sharper more technical or business like.
These observations are generalizations of course.