Mulcahy, Lisa, Stage Directions
Create smashing strobe lighting SFX safely - even with a big cast and capacity house
Strobe light and flashing SFX can be a real visual boon to a production, or a real pain in the neck. The more people involved in these effects - cast, crew or audience - the more things can go wrong. Crew members and actors have to be well-rehearsed to move properly under the disorienting effects of strobing, and some audience members can actually suffer medical problems (such as seizures) when viewing strobes. Still, strobe lighting can be an incredibly versatile tool, and a great way to add pop to your show.
Strobes come in a number of prices ranges and wattage, from the traditional halogen or xenon lamp to the recent arrival of LED sources. Your basic strobe is a plug-in device like the American DJ Big Shot, a 45-watt light with a halogen source. There are more complex, multiple source fixtures like the MegaStrobe FX12 from Chauvet Lighting, which contains multiple LEDs, is controllable via DMX and can be used as a singular strobe light or programmed to have chase effects in the fixture. On top of the power scale you have instruments like the Martin Atomic 3000 DMX, which uses a 3000 watt xenon lamp to blast your viewers; Paule Constable used eight of them for her lighting design for War Horse on Broadway.
No matter the size, strobes tend to pack a powerful punch, so you've got to carefully plan them into a production. A few short, dramatic flash bursts lensed in white can perfectly mimic vivid lightning; you can also create unique stage pictures with colored strobes; and you can also use a strobe to light a slow-mo visual tableau. Just don't do them all.
"When using strobe or flashing effects, I think it is important to remember that there are people watching your show, and that, while strobes lend themselves to great effects, using them too often or for too long leads to the audience becoming annoyed by them," says Kevin Richie, president and co-owner of StageSpot. com, a retail production supply company based in Austin, Texas and a veteran Broadway and regional lighting tech.
Additionally, where you place a strobe can have a tremendous impact on how well the effect will read from the stage. A strobe flash that originates too close to another source of stage light is most likely going to get swallowed up and washed out, either partially or completely. Placing a strobe upstage, away from clashing light sources, will maximize its impact. It's also not a bad idea to take the intensity of the rest of the rig down a few points around the timing of a strobe to avoid washing the effect out.
Keep in mind, too, that the closer an audience member is to a strobe, the more vivid (and potentially, visually assaultive) its result will be. Don't overwhelm the audience! "More typically, strobe lends to a better effect when the flash can be contained on stage," adds Richie.
Health and Safety
Unfortunately, another effect strobe lights can have on your audience, as well as your cast, crew and staff, is creating potential health hazards. "We know that strobes can trigger seizures," stresses Noemi Ybarra, lighting specialist at Jones & Philips Associates, a theatre consulting firm in Lafayette, Ind. Audience members with photosensitive epilepsy, specifically, can suffer seizure episodes by looking even briefly at a strobe SFX.
The number of strobe flashes you program per second can influence a susceptible audience member's seizure risk. It's believed that an effect containing eight or more flashes is most likely to cause a medical issue. Many theatre safety experts, therefore, caution clients never to operate a strobe at more than five flashes per second. Don't put any patron at potential risk: Consult a doctor, and ask this physician not only to inform you accurately of seizure risk in accordance with your production, but to come to your rehearsals and personally view your strobe SFX to confirm its safety. …