3 Point Lighting Research
High Key
High-key lighting is a style of lighting for film, television, or photography that aims to reduce the lighting ratio present in the scene. This was originally done partly for technological reasons, since early film and television did not deal well with high contrast ratios, but now is used to suggest an upbeat mood.
Low key
Low-key lighting is a style of lighting for photography, film or television. It is a necessary element in creating a chiaroscuro effect. ... Low key light accentuates the contours of an object by throwing areas into shade while a fill light or reflector may illuminate the shadow areas to control contrast.
Fill lighting
A supplementary light used in photography or filming that does not change the character of the main light and is used chiefly to lighten shadows.