Lighting is a vital and very detailed part of filming there are many different ways of which it could come across in a frame. there are also different forms of lighting that occur many times depending on the genre of the film and also the emotion that the director wants to evoke from the audience.
The Key Light - The key light is the brightest and the most influential light, it is used to highlight the form and dimensions of the object. it is a way in which a silhouette effect can be created. The key light can be hard and focused or soft and subtle depending on the set up and the mood of which the director is aiming for.
Back Light - The Back light helps counteract the effect of the key light or creates an outline or silhouette. this is a very effective way of creating mystery in a scene because the audience is not able to see the features of the character, it is sometimes called the kicker or the rim light because it often gives characters an angelic halo type effect.
The Filler Light - The filler light helps soften the harsh shadows that the use of the key and back lightings create.The filler light crates a brighter and smoother look to a scene, it is very often used to make a film glow in appearance and vivid.
all these forms of lighting are used in a three point set up to create contrast between the background and the centre object but also to produce a three dimensional effect.
Under lighting - This is when the main source of light comes from below the subject. it is used in thrillers and horror films to make the subject look more sinister and powerful. it is effective because the light scatters all over the subject and creates a lot of dark shadows that help to horror .films that more frightening.
Top Lighting - this is the complete opposite of Under lighting because the main .source of light is coming from above, highlighting the features and is used to crate a glamorous look, the subject.
Low Key Lighting - Low key lighting is created by using only the key and back lights. This will produce a sharp contrast of light and dark areas on the screen as very deep, distinct shadows are formed. it tends to portray a sense of alienation which may be why it is mostly used in horror films.
High Key Lighting - There are a lot more filler lights used to make the object more realistic, it may also be used .to suggest a more up beat mood, high key lighting is very luminous and free from harsh shadows, using high key lighting does not need as much adjustment so it can cause shooting times to contract.