high key

A bright background is needed when shooting with high key lighting, such as a white seamless paper, other alternative backgrounds include a white muslin background or a backdrop that is nuked with lights. you can achieve a high key lighting affect a high key lighting affect by setting up multiple lights. this set up will give you total control over the image. also is a style of lighting for film, television, or photography that aims to reduce the lighting ratio present in the scene. 

mid key

mid key keeps the photograph tones right in the middle of high and low key- not too bright and not too dark. mid key lighting focuses on the middle tones in a photograph, while still keeping the subject brighter than the background. with mid key lighting you have more room to play with photographic backgrounds. if the subject is closer to the light, it will appear brighter than the background, achieving the perfect look for medium key lighting.

low key

one of the most dramatic  effects that you can get on backdrop photography is the low key lighting effect. this effect is produced when a subject stands out against a dark background. the idea is to get dark tones while using very little lighting. the emphasis is placed on one spot of the subject as opposed to details everywhere else.