Green screen is a highly effective way to add additional visual information that can be edited alongside and behind the presenter. It is what broadcast TV does.
The format that information can be created and edited in is very variable – text, graphics, images, video and animation. Editing is done during post-production or live via a mixing desk. This is the method that is used for TV weather reports and election night updates.
Green screen is really a pallet that allows us to customised what the audience sees. It maybe impossible to film someone in a manufacturing and production setting due to noise or health and safety issues.
So by filming the background – without a presenter being there – means we can add it later. This gives a great deal of creative flexibility.