Uses for green screen

For this module I am going to learn how to green screen and use the techniques learnt to do it myself in my film. I wanted to look into what green screens are used for and how this will help my module and what I could possibly use it for.

The most common use for green screens is to replace a background, this is usually seen in modern films with lots of visual effects, where the actors and perhaps a small section of a built set is in front of a green wall/screen and in post the whole area can be picked out and replaced with a digital environment or different film footage of a different area. Everyday examples of green screening is the weather reports on the news, where the forecaster is stood in front of a green background, and the film footage of the presenter is layered on top of the weather map. 

Another example is Photo Booth, the app for Apple based products, where you are able to take pictures from the Mac/Ipad's camera and there are options to change the background. Although this isn't green screening it uses the same principles, where a still back plate is taken first and then when people come back onto the screen it detects a change of surface and only shows the video footage of them. With green screening it is similar to when elements such as stands, armatures and wires need to be taken out, where a clean back plate is taken of just the background. When the film is being taken these elements are coloured green, so in post they are able to pick the green areas out, leaving the live footage and the background. The areas that were once green will now be clear which allows them to put the back plate behind revealing what would have been seen before these elements obstructed the view.