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:
“I pity the men whose natural pleasures are burthens, and who fly from joy ... as if it was really an evil in itself.... Poor unfortunate creature that he is! as if the causes of anguish in the heart were not enow—but he must fill up the measure, with those of caprice; and not only walk in a vain shadow,—but disquiet himself in vain too.”
—Laurence Sterne (1713–1768)
“The Transcendentalist adopts the whole connection of spiritual doctrine. He believes in miracle, in the perpetual openness of the human mind to new influx of light and power; he believes in inspiration, and in ecstacy.”
—Ralph Waldo Emerson (1803–1882)