How does it work with the blue wall ?

[Simon total war]

In historical movies they use a blue wall behind the actors, to add later on a background ( castle, mountains ) how could I do this at home ?? If I am making a home Medieval movie and I want a background of a picture and let say I am filming infront the blue wall ??:hmmm:

[zYn]

You would need an video editing program like Adobe Premier and then filter out the blue color. That means don't use blue yourself.