The basic concept involves using a large green backdrop during filming, which is later replaced with anything you can think of, using chroma keying. For chroma keying to work, a green screen room must be flat and uniform, requiring careful lighting to ensure no shadows or detailing.

A camera - either a webcam, smartphone or a real video camera. A green screen - the background itself that can be both portable and relatively inexpensive. Two lights - have a separate light source for the background and the object. A computer - where you will do the removal of the background.

A green background has a much higher luminosity than a blue one, making a green screen a better choice for daytime scenes when you want your shots to look bright and well lit. But a blue screen can be handy in scenes where you don't need so much light.

Using a green screen allows the filmmaker to layer any background with the subject being filmed or photographed. The subject is filmed against the green (sometimes blue) background, which is replaced in post-production by a digitally generated background.