Lighting 

there are there basic point of lighting which can really affect the feeling of a certain shot within a movie.

• Key light- which will present the actor and can cause some effect as well in the scene. the key light will create a shadow which will create contrast on the actors face causing a dramatic effect to that scene.
• Fill light- which will break the contrast of the face of the actor by filling the shadowy side of the actor face with light giving it a more flatter feel.
• Back light- will push the actor away from the background so that it doesn't look as if the actor is blending in with the background.
• Background light- this light will irradiate the background/set and depending on the lighting will establish a low or high key mood

High key mood

this is the kind of background lighting that you want if you a more balanced lighting and would be more useful with sitcoms comedy ect. the contrast ratio would be for high key mood 1:1

low key mood 

this is the kind of background lighting that is more dramatic with a lot more contrast. this would be for more crime thrillers and horror. the contrast ratio for low key mood would be like 1:8