Design How should i cut out spill from my lights

[fumb3l]

I do lighting for plays, events, and school band festivals in a theatre with two cat walks. Most of my lights are on second catwalk and almost always- unless Im lighting the orchestra pit- ambient light spills from the lights onto the front of the first cat walk. How can i get rid of this? The cat walk is painted a color of red which seems to reflect the light a lot so it looks unprofessional. Ill admit that i am a High School student but i do intend in going to college for this line of work. Someone suggested i put a (i call it a top hat) cover over the lekos but we don't have any. I cant seem to shutter it out. Is there something i can slide in or wrap around the front of the lens? Or is this even possible to do. I even have a similar problem with my electrics with spill onto the front of the legs curtains.

Help?

 

[theatricalmatt]

Top hats go in front of the fixture, where the gel slot is, and effectively limit the amount of spill (but potentially also coverage) that the light puts out. A half-hat does the same thing, but only covers half of the light. It's useful for cutting off architecture -- including catwalks. Both are fairly inexpensive unless you need them in multiples -- presumably all of your front of house lights might need them. Rental houses also let them out for cheap.

You can also use a shutter (inside the fixture) or a template holder (perhaps with a custom made template) which will allow you to make a strong, sharp edge if you want one. Adding blackwrap to the front of the fixture, effectively making your own top hat / barndoor, will also work, but you won't be able to get a crisp line. You could also look at adding some neutral density, or very dark color gel, to cut down on the light bouncing off the catwalk. Gel and blackwrap are cheaper than top hats, but you might not be able to use them on more than one show.

 

[de27192]

I concur about using top hats, if you can't afford or simply can't get hold of top hats for your lanterns, they can easy to make - providing you can source gel frames.

Buy some aluminium air-con duct to the same diameter as the 'O' in your gel frames. Cut a short piece, probably 3-4" long, and then cut short 0.5"-1" slots in the end, so you can fold them out to form tabs. Cut most of these off, leave 4 tabs attached. Then rivet these into the corners of a gel frame. Finish it by applying a caulk sealant around the join. You can get high temperature sealant, high enough for that end of the lantern anyway.

I made up a load of top hats this way and they work fine.

 

[DELO72]

I always prefer to use a good can of Beam Stop. You just spray liberally around the area of the stage you don't want the light falling onto. But on a serious note- if it's from the front, top hats for fresnel/PAR fixtures, and donuts for ERSes.

 

[robmerow]

Rosco Matte Black Cinefoil. It won't look as clean and professional on the actual fixtures as a proper tophat but is a cheap and effective way to make a quick shield to block out spill.

 

[kicknargel]

First, it may be worth looking into some maintenance. Dust on the reflector and lenses acts as diffusion and scatters some of the light. Maybe be time for a cleaning. Also, check the bench focus of the fixtures. Next, are you focussing the light with as sharp an edge as you can (without being so sharp it's noticeable on stage)? You're not using any frost or diffusion are you? These things together may make your shutters effective enough to cut off the architecture.

If you still need more, then as mentioned top hats are the ideal solution. Using a donut is less ideal but may help. This is a piece of metal that goes in the gel slot and has a hole slightly smaller than the lens diameter. You can buy them or cut them out of blackwrap. These cut spill but also cut total output. They're used mostly to improve the crispness of gobo projection.

 

[microstar]

I agree with kicknargel, sounds like a huge layer of dust on the lens and/or reflector acting as diffusion, or terribly out of whack lamp alignment.
I would definitely check those aspects before anything else.

 

[derekleffew]

While I agree with the above posters (except for the donut part, which I've never found effective as an anti-spill device), here's what I would do:
Buy a roll of BlackWrap (MSRP $22 for 12"x50' roll) or Cinefoil (both essentially thick black aluminum foil) from your favorite friendly local dealer. Cut a piece 1/2" larger than the colorframe (so 6.75"x6.25" or 8"x7.5"). Fold that extra 1/2" at 90° and insert that into the top of the gelframe along with the color. You've now created a "visor" of sorts which should block most, if not all, of the undesirable light on the ceiling. If too floppy, fold over 180° and crimp the edges to reinforce. Not nearly as clean as a half hat, but effective nonetheless.