Projector setup halloween question

[alucard76]

Hi all. New here. I've set up a projector with my macbook pro. I've got it beaming video onto my window blinds and it's awesome. Problem is, the effect I want is for someone from the outside to be able to look at my window from the street and see black and white shadows of the scenes being played. Right now when I walk outside I see the color video coming through the blinds and it's cool but not what I want. Essentially, on halloween night I want people to walk by the window and see awesome shadows. Am i even being close to clear?