Props are perhaps the most difficult pieces of the continuity puzzle. Carefully work with your actors to make sure they handle the props exactly the same way every time. Make sure the props department records which props are used during which scenes. Again, in Lord of the Rings: The Two Towers, Gandalf and company enter King Theoden's chamber. As Gandalf walks toward the camera, he holds his wizard's staff vertically. In the rear angle shot, however, he is holding it horizontally. At the next cut, the staff is now upright, and at the following cut, the staff is horizontal again.

During every take, the action must be the same. Make sure your actors know what movements they are making during the lines they are speaking. They must maintain these movements for every shot. This can be difficult because the cover shot - or wide shot - might have been taken hours, if not days, before the closer shots. A continuity note should be made, so that the actions can be duplicated.

In Ocean's Eleven, Linus and Rusty are talking in the Botanical Gardens of the Bellagio. Rusty is eating a shrimp cocktail that changes from a cocktail glass to a plate and back again. In American Pie, during one bedroom scene, a girl is holding a clear cup of beer. In the next few shots, the cup goes from clear to blue and then back to clear. These are unusual mistakes, because props people always have very specific props for each scene. Maintain a strict props list, and always refer to it when setting up each shot.

In Dick Tracy, when Tracy is talking to the boy over a glass of milk in the restaurant, the level of the milk constantly changes. Using props that the actor drinks, smokes or eats can be a continuity nightmare. The only way to prevent this kind of continuity problem is to try to shoot in sequence and keep track through photos of consumable props for each step of the sequence. If the actors take a drink, note it and the level of the liquid. If they are smoking, keep track of the length of the cigarette or cigar and, if they are eating, maintain the correct remaining portion throughout the sequence.

Maintaining continuity can be a difficult task. However, if you maintain a detailed record of every scene, with supporting pictures and script notes, you should be able to avoid family, friends and clients pointing out the little continuity problems that can creep into your production. Just keep your eyes open for the little things.

Contributing editor Dr. Robert G. Nulph teaches video and film production at the college level and is an independent video/film director.