I was experimenting with green screen at my friend Vamsi house in Edmonton. It is easy to remove the green pixels with Adobe Premiere. However, it was very difficult to shoot with even lighting, thereby making the removal of green pixels a bit cumbersome. It was fun to see how the application of image processing technique (chroma-keying) is applied in reality (Well, most movies are shot in green screens these due to their obvious advantages. As a one-liner, it is just removing the green pixel in the actual image and replacing it with the corresponding pixel of the background image. Blue screen also works fine. Whenever you shoot in green/ blue screen make sure that actors do not wear clothes that has green/blue on them. Red screen does not exist because it matches with the skin tone of the person.