Ask anyone not connected with shooting – and a good many people who are – what they immediately think of when the term ‘continuity’ is mentioned. Many believe it is a question of avoiding an accidental total change of costume from one shot to the next, or props appearing in different places from shot to shot, or things suddenly disappearing … and so on.
There is a good deal more to continuity than maintaining consistency in costume and props, but those are often the most noticeable.
Dressing props are those used to dress the set but are not handled by the actors. Take a Polaroid picture of the set or draw a diagram. This is useful if you are working for several days on the same set or for reference in the case of a shot being retaken.
Action props are those used by the artists in the course of the action of a scene. It is most important that you pay particular attention to these props: when the artist uses them, which hand they are held in and at precisely what point in the dialogue these actions occur.
If the action props are reset in exactly the same way then the artists will integrate their use with the dialogue and they will be used in the same way and at the same time in the scene. If the props are reset in different positions, the artists will not get used to handling them and the timing of the actions in relation to the dialogue will be different.
Note the general position of the props by drawing a diagram or taking a Polaroid photograph, but only worry about the props that will be used in the action.