a theater director uses projection in their show and wants a 10,000 (or more) lumen projector to light up screen, and illuminate actors standing in front of the screen.

Is this dangerous? I brought my objection up in a meeting and they said they have done it before. I feel rear projection is better as far safety.

Any thoughts.

It depends quite a bit on how large the screen is and the throw distance from the projector.

That being said, the safety of this should certainly be considered. And just because it has been done before, does not by itself make it okay .

 

Laser projectors of high output come with an exclusion zone where looking directly into the beam could cause retinal damage, outside that zone they are generally considered to be safe. I have a 17,000-lumen projector and the exclusion zone is about eight feet from the lens.

Art

 

Hi Art thank you so much. So this means if the actors are let's say 12 feet from the projector that any light getting into their iris is not strong enough to cause damage? Also they will be in this position for an extended period of time, perhaps 30-45 minutes at a time. Might that factor in?

 

With front projection, the actors will cast shadows on the screen, and the projected image will be on them as well as on the screen. With rear projection only the side of the actors facing away from the audience will be illuminated. I assume that the projector is showing an image and not just a large light beam. If it's just an illumination beam, why not use spot lights?

 

HMS17B - Hi yes that's the idea - the image will be projected on the actors as well as the screen and okay if there is a shadow. Again this is not my concept, I'm just trying to make sure it's done safely.

 

Caution - as a retired personal injury attorney - why subject yourself to something like this where there may be some risk to your eyes and vision. The director wants to do this and will likely gloss over any safety risks. Its like being in an experiment. To participate in something like this you shouldn't have to extensively research to make sure its safe. After the fact, after injury has occurred, its too late to go back. Let others be the guinea pigs.

 

How big is the venue? 10K lumens in a midsize theater is above average but not crazy. It wouldn't be unusual for the spotlights hitting the stage of a large arena to be 50K+ lumens.

Angle matters a lot too. Experienced actors will be accustomed to shrugging off spot lights that would dazzle someone who instinctively turns their head the "wrong" way, but this requires careful blocking to ensure the audience can read their expression while they look/gesture the intended way.

 

This type of thing, using standard film-based and digital projectors with likely as much or more light, have been used on live stage presentations for many decades. Despite that I'd look into the distance from the performers as a layer of safety.

You might find this informative and enlightening

NEW OPTICAL SAFETY DISTANCE STANDARDS FOR CINEMA PROJECTORS - European Digital Cinema Forum

Art

 

I was the technical director for a 2600 seat concert hall for a decade or so, in a previous life . We had four Strong Xenon Super Trouper spot lights, each capable of 16000 fc at 50 ft. For many performances, the lead performer might have 2 focused on him. We were able to pop balloons with them, but no one ever had their vision damaged.

 

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Naturally, I spent the intermission sneaking peeks at the booth & the gear. They use 4 Panasonic PT-RQ22 projectors in huge commercial hush boxes cantilevered off the Parterre. That's 80K lumens of video aimed at the stage before you even get into the actual lighting cues.

 

Christie (used to) own a German company that's server/player technology including the option to map on moving actors, tracking their movement. Christie: German Entrepeneurs To Buy Back Pandoras Box | invidis, so there are a few specialists.