A composite is a picture made up of several parts, normally the subject and a background, but it may be much more complicated than that, involving many layers to make the parts blend correctly. A green screen composite uses a green screen as a background.
Why Green screen?
Using a green screen allows the photographer to remove the green background and replace it with something completely different. Green is used as you do not normally get any green in skin tones. This allows the subject to be extracted easily – but you may have to watch out for green clothing and accessories!
