Lang Thompson Wrote: >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"?). No. rear projection and Green screen are 2 differnt things. Rear projection is just that; the images are projected onto a screen behind the scene and sync'd to the film camera. Green or Blue screen provides a colour that can be matted out in post production with a background plate. >Why >green instead of blue? Are both colors used, according to costumes etc? >Is there some technical advantage to green? The reason green might be chozen over blue is that perhaps there are some blue colours on the subjects to be filmed, and the matting process would also eliminate this object (not desired) as well as the screen behind (desired). You can actually choose any primary colour for the matte process, I understand. It is crucial that the lighting of the subject be well seperated from the blue background and that no spill occurrs. If blue hits the outline of the subjects, then tearing can occurr. Usually seperate lights backlight the subject with an orange colour to cancel any possible blue spill. One company dedicated to Blue screen photography in L.A. is Out of the Blue Productions. Brian McGugan Brian McGugan Box 15699 Main Post Office Vancouver B.C. Canada V6B 5B4 _/_/_/ _/_/_/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/_/ _/ _/ _/ http://www.ffa.ucalgary.ca/artists/bmcgugan/index.html Motifs and Repetitions, my first short film: http://www.imag.net/~goog/ ---- To sign off SCREEN-L, e-mail [log in to unmask] and put SIGNOFF SCREEN-L in the message. Problems? Contact [log in to unmask]