Fill light

In television, film, stage, or photographic lighting, a fill light (often simply fill) may be used to reduce the contrast of a scene to match the dynamic range of the recording media and record the same amount of detail typically seen by eye in average lighting and considered normal. From that baseline of normality using more or less fill will make shadows seem lighter or darker than normal which will cause the viewer to react differently, by inferring both environmental and mood clues from the tone of the shadows.