P1. RESEARCH AND UNDERSTAND GREEN SCREENS

Technical term for green screening is - Chroma Keying, it's a special effect and post-production technique for compositing two or more images or videos that flow together based on colour hues (chroma range). This technique has been used greatly in many fields to remove a background from the subject of images or videos especially  motion pictures, weather casting and videogame production.

The commonest colour that has been in use during past decades as a background or chroma key is blue. As technology developed, film makers discovered that green was a better colour. In the year 1970, the colour blue in chroma key was finally transformed to the colour green; which also became famous in video edditing and photography. One of the reasons why blue was exchanged for green coloured screens is because of the fact that the colour green is better held in by digitalis.
Main key points of green screening and why is used often these days is to create background that is realistic to the audience and is easier than travelling to find the location needed such as going to Egypt. Companies use green screening because it can be financially cheaper. This doesn't allow tourists or attraction from passer-by to interrupt shooting the film, or worry about members of public way of living. There are many different things that the director needs to consider when shooting on location for example: background noise outside which could stop the actor from delivering their dialogue clearly. It's also a lot cheaper using green screening then having to travel to another country which then leads to taking out a permit and insurance fro the cast and equipment.
To do green screening, you use a green sheet and cover over a smooth/straight surface, so there's no creases visible and making sure that the lighting is all the same so you wont get a paler shade of green- this could make the image or video unrealistic if it can be seen. Then the film is transferred onto computer to add visual effects and to drop the background image to the green areas.

From 0:26-0:40 is the short clip I've focused on.

This short clip from 'Ugly Betty' used green screening. (The background story of this TV program is based in New York city and a plain nerdy girl called Betty works at Mode one of the elite fashion magazines). However because it's set in NY this means this program is going to use a lot of green screening, this is because if they had to go out to the location to shoot this in particular scene it would of taken longer then shooting it in a studio. NY is very busy city and to have capture this shot you can see at 0:29 if they were on location police would have to stop the public from walking through the footage because you would never see hardly anyone walking around at rush hour. Directors would have to think about traffic (noise pollution , members of the public interrupting would have to stop and start wasting time and not being able to hear Betty's dialogue because of the noise and interruptions from the public.