This sequence of shots is one of the most amazing in the DS9 episode. The special effects artists were able to mask out two of the original characters and replace them with DS9's O'Brian and Bashir. Again, the best way to shoot the new actors would be on a blue stage. What you will also notice is that by removing the red shirt character and replacing him with the blue shirted Bashir, they had to create some of the blue shirt next to Bashir. In so doing you will see that the red shirt to this man's immediate left was virtually eliminated. His head is still visible, but his shirt isn't. The second difficult aspect of this shot is that the moving Kirk was masked out as he passes in front of the inserted characters. There are eleven frames during which Kirk moves in front of Bashir and then O'Brian. Moving masks are much more difficult than relatively static ones, and there are no noticeable jitters. I received this great email note from David Yee about the extra whichO'Brian replaces: The nameless extra that Kirk was browbeating in the lineup (that O'Brian replaced) was William Shatner's fight double. Amusing that O'Brian got him confused w/Kirk when he saw him in the Bar, huh? J. Trent Adams is a new media producer specializing in direct-to-digital video production. He designed and continues to produce the first nightly video webcast.