Low key lighting leaves large, prominent areas of dark. This kind of lighting tends to be somber—serious, formal, and dignified in mood. Low-key lighting requires more side and back lighting.
High key lighting has an abundance of bright, diffused light, resulting in slow-falloff of flat lighting.
The technique uses three lights called the key light, fill light and back light. Naturally you will need three lights to utilise the technique fully, but the principles are still important even if you only use one or two lights. As a rule:
This is the main light. It is usually the strongest and has the most influence on the look of the scene. It is placed to one side of the camera/subject so that this side is well lit and the other side has some shadow.
This is the secondary light and is placed on the opposite side of the key light. It is used to fill the shadows created by the key. The fill will usually be softer and less bright than the key. To achieve this, you could move the light further away or use some spun. You might also want to set the fill light to more of a flood than the key.
The back light is placed behind the subject and lights it from the rear. Rather than providing direct lighting (like the key and fill), its purpose is to provide definition and subtle highlights around the subject's outlines. This helps separate the subject from the background and provide a three-dimensional look.
Hard light leaves hard-edged shadows – they are well defined with a clear border. The best example is the shadow from sunlight in a clear sky.
Soft light leaves blurry-edged shadows. When they’re slightly soft you can still make out the shape of the object casting the shadow. A super soft light almost makes believe there’s no shadow, the best example being an overcast day.
Specular light is light that is brighter at the center and then tapers off at the edges. The entire beam doesn’t have an even concentration of light. The light from a torchlight is the best example of this.
Diffused light is light that has an even concentration of light across the beam. It’s as if someone threw a light blanket on the object. Whatever is illuminated is illuminated evenly.
But to diffuse a soft light, you need to make sure the large source also provides an even spread of light across the beam. You can do that in two ways:
It’s for this reason some pros use a book light, which is a bounced source that is further diffused so the light is as diffused and even as possible, yet soft because of the large size of the frame.
Gold & Silver Reflector = Warm Light
Frosty Filter = Diffuser
Orange Filter = Tungsten
Light L.E.D = Daylight