Having started a Macbeth trend on Bardfilm, I find it difficult to stop, particularly as I have a backlog of Macbeth material almost as large as Birnam Forest.
The dagger speech proves particularly interesting in each new production of Macbeth I encounter. It can be the key to so much of the rest of the production. It can speak to Macbeth's resolve (or the lack thereof), Lady Macbeth's control over Macbeth (or the lack thereof), the production's use of special effects (or the lack thereof), and the skill (or the lack thereof) of the actor playing Macbeth.
One of the Folger Shakespeare Library editions of the text of the play comes with a DVD of the play as directed by Teller. Yes, Teller—of Penn and Teller fame. Teller is the part of the comic duo of magicians who virtually never speaks during their routines.
I don't know whether this special effect is a Pepper's Ghost trick or not—I'm really not qualified to tell a Pepper's Ghost from a Salt's Dik-dik—but the effect is striking. Macbeth, having looked himself over in a huge mirror, sits with his back to it. Soon, a dagger appears in the mirror—but not in the reality the mirror supposedly reflects:
The film is full of interesting and entertaining tricks like that. On the whole, it's a good, solid, dependable production that is quite useful for classroom discussion.
By the way, my copy of the DVD automatically includes Teller's director's commentary, and I'm always sure to turn that off before watching the play.
Links: The Film at IMDB.