On Stage effects

I have done many productions of "The scottish play" as an effects designer and although I have tried many effects I still think that the most effective is a small stage flash pyro. Use a white pyro (coulored ones arn's at effective) and ensure that it is placed directly in the audience's line of sight to the actors. (or at least as close as is practicable). The flash produced doesn't need to be enough to cover the actors completely but it is important that the audience is made to look directly as the source of the flash as it goes off......putting the flash right in front of any action that may be happening on stage just before the effect is good.....if not generating a sound effect from a speaker right next to the pyro (or directly in the line of sight of the pyro) will usually make the audience look in the right direction just as it goes off.
The actors need to leave by a quick exit a split second AFTER the flash while the audience have lost the use of their retiners but ensure they do not make any movement before it, or the effect will be lost.
It does take good timing and a bit of choreography with the mice etc but it is a very good effect and works at least in part because the audience will not expect it to happen........so don't be too worried if you look at it yourself and can tell exactly how it was achieved.....remember the audience have not been at all the rehearsals and have not actually seen design of the effect.

hope it all goes Well..

Matt