I saw a making-of doc on "Air Force One" which showed the actors filming in front of a green screen (is this still called "rear projection"?). Why green instead of blue? Are both colors used, according to costumes etc? Is there some technical advantage to green? Lang Thompson http://members.aol.com/wlt4/index.htm (with a new section on HK films) ---- Screen-L is sponsored by the Telecommunication & Film Dept., the University of Alabama.