In television, film, stage, or photographic lighting, a fill light (often simply fill) may be used to reduce the contrast of a scene and provide some illumination for the areas of the image that are in shadow. A common lighting setup places the fill light on the lens axis, roughly perpendicular to the key light.
The fill light is often softer and, by definition, less intense than the key light. The ratio between light and shadow depends on the desired effect. For example, a fill light that is a small fraction of the power of the key light will produce very high-contrast or low-key lighting, while filling with half or more of the key light power will produce a high key, low-contrast tone.
In cases where the fill light is desired to be darker than what is available without artificial means, a flag or frame may be used to block ambient light and thereby provide what is called negative fill.
An alternative to using a direct light source as a fill is to re-direct or "bounce" the key light towards the subject by using a reflector.
Famous quotes containing the words fill and/or light:
“To fill the hour,—that is happiness; to fill the hour, and leave no crevice for a repentance or an approval. We live amid surfaces, and the true art of life is to skate well on them.”
—Ralph Waldo Emerson (1803–1882)
“As one child psychologist friend of mine explains it with tongue in cheek, your baby only needs a lot of light at night if he’s reading or he’s entertaining guests.”
—Lawrence Kutner (20th century)