Backstage lights ideas

[curtis73]

I recently remodeled our blackbox and included a full upstage crossover by not installing the lower shelves on some pallet racks. Since the pallet racks are covered with a traveler curtain, it makes a 4' wide crossover for the whole upstage wall.

Instead of hanging a bunch of blue worklights, I wanted to line the bottom of the shelf with blue LED tape. I have used LED tape a LOT in my builds and most of the cheap ones are just that... cheap. I used some LED tape under the lip of our concessions bar and it lasted about 4 years before the COB emitters began failing, one of them decided to randomly stop working and I noticed a big green spot of corrosion in the conductor on the tape. Nice stuff for a one-month run of a show in a light box, but not the greatest for a permanent lighting solution.

What I want is a blue LED strip that is dimmable and with quality to last a long time so I'm not surprised on tech night two years from now that they don't work. I have surfed around SuperBrightLEDs and they are more expensive, but they may have the same suppliers as Amazon. Price doesn't necessarily equal quality. Dimmable is necessary. Doesn't need to be DMX. If I want DMX in the future I have some encoders I could hook up to it. Bi-color (blue/white or RGB) would be nice so they can switch to work lights after curtain call, but not necessary. I could install two strips - one blue and one white, but RGB might also be nice so I can pick different ends of the spectrum depending on the warmth/coolness of the lighting design.

Ideas for quality LED strips?

 

[SteveB]

The only truly dimmable LED system is going to be one that has a DMX capability. Dimming line voltage stuff is always hit and miss and generally not useful below 15-20% of input voltage and you will probably get some form of pop on at about the same percentage when turning on, though for your purpose might not matter. The low voltage power supplies just cannot deal with reduced line voltage at certain points.

 

[NJLX]

I don't have a current recommendation on LED tape, but if you go with a single color(or want a knob per color), I've used these to dim LED tape in my bedroom closet for the past 5 years, absolutely no issues. This appears to be the same product: https://www.amazon.com/dp/B00I5T3PKK/?tag=controlbooth-20 since the ones I bought are no longer available on amazon. Just do the math and make sure you don't overload it.

The LED tape dimmed by these has also been going strong for 5 years, but as with most amazon LED tapes, is no longer available. I did go with one of the waterproof options, with the theory that it would last longer since it's fully encapsulated - only complaint is that the waterproof covering gets cloudy over time, but that just helps diffuse it a bit.

 

[theatricalmatt]

From my experience the longevity of LED tape installs has less to do with the quality of the tape and emitters, and more to do with how the LED tape is mounted. It helps *tremendously* if you have an aluminum channel with a clear or frosted plastic extrusion over it, which keeps the LED tape firmly secured, provides strain relief, prevents accidental bumps and scrapes, and all the other good stuff.

 

[almorton]

Those dimmers as linked to by @NJLX are absolutely the right way to dim low voltage tape. They don't alter the line voltage, since they go in the low tension circuit; they work, as the wording on the dimmer suggests, by pulse width modulating the power to the tape, which is how DMX low voltage dimmers work. If you're handy with an Arduino, making your own dimmers is a cinch - just need a potentiometer to set the level, and a power MOSFET to switch the 12V/24V power, and a couple of lines of code.

 

[cbrandt]

Take a look at Environmental Lights. They're a great supplier that stands by their products. They aren't the cheapest price on the market, but they're also far from the most expensive either. I've used their stuff in quite a few builds, and never been disappointed.

 

[curtis73]

The only truly dimmable LED system is going to be one that has a DMX capability. Dimming line voltage stuff is always hit and miss and generally not useful below 15-20% of input voltage and you will probably get some form of pop on at about the same percentage when turning on, though for your purpose might not matter. The low voltage power supplies just cannot deal with reduced line voltage at certain points.

Sorry... I wasn't talking about taking LED tape and putting it on a dimmer, I'm talking about the ones they sell that have their own PWM mod box. I have several in my house with a little rotary knob inline on the power cord. I wouldn't use voltage/potentiometer, I would use a dimmable kit. In the future I can see going DMX just because I can. That way we can just include a cue that takes out the whites and brings up the blues backstage without having that extra step to remember.

I also keep forgetting to mention that we're a small community theater, so this isn't like a $5000 retrofit. This is me and a $100 Amazon gift card we got as a donation.

 

[curtis73]

I don't have a current recommendation on LED tape, but if you go with a single color(or want a knob per color), I've used these to dim LED tape in my bedroom closet for the past 5 years, absolutely no issues. This appears to be the same product: https://www.amazon.com/dp/B00I5T3PKK/?tag=controlbooth-20 since the ones I bought are no longer available on amazon. Just do the math and make sure you don't overload it.

The LED tape dimmed by these has also been going strong for 5 years, but as with most amazon LED tapes, is no longer available. I did go with one of the waterproof options, with the theory that it would last longer since it's fully encapsulated - only complaint is that the waterproof covering gets cloudy over time, but that just helps diffuse it a bit.

Thanks for the links. I also have a couple of these for when I go DMX. I have wireless DMX but I only have 7 receivers and don't want to spare one for this project, so I could hook up an RGBW strip to these... but I would have to run physical DMX cable to the backstage area. I think I might grab some of those PWM dimmers you linked for now.

 

[curtis73]

Those dimmers as linked to by @NJLX are absolutely the right way to dim low voltage tape. They don't alter the line voltage, since they go in the low tension circuit; they work, as the wording on the dimmer suggests, by pulse width modulating the power to the tape, which is how DMX low voltage dimmers work. If you're handy with an Arduino, making your own dimmers is a cinch - just need a potentiometer to set the level, and a power MOSFET to switch the 12V/24V power, and a couple of lines of code.

I'll respond by quoting your post and editing for how I read it

Those dimmers as linked to by @NJLX are absolutely the right way to dim low voltage tape. They don't alter the line voltage, since they go in the low tension circuit; they work, as the wording on the dimmer suggests, by pulse width modulating the power to the tape, which is how DMX low voltage dimmers work. (I understand that part) If you're handy with something that sounds like an Italian Mobster, Greek Greek Greek, Potentiometer and power a MOSFET, and a couple lines of Greekity Greek.



I still have actual wound transformers in my electrical arsenal. The whole PWM thing I get. I'm woefully behind when it comes to modern tech. I'm enrolling in a Dante training in anticipation of getting a digital desk because my IT skills consist of knowing what IT stands for.

P.S. What does IT stand for? (kidding)

 

[ChrisGLightingD]

Another idea would be to use EL-wire (electroluminescent wire). Unlike LED tape, this is a continuous glow. It cannot be dimmed to the best of my knowledge, so it'd have to be an on off situation, but I have loved using this technology.

 

[microstar]

Another idea would be to use EL-wire (electroluminescent wire). Unlike LED tape, this is a continuous glow. It cannot be dimmed to the best of my knowledge, so it'd have to be an on off situation, but I have loved using this technology.
View attachment 22700

I have dimmed EL-wire with a variable DC power supply feeding the EL inverter unit. Worked fine but I didn't need to hold it at a low level, just a reasonably quick fade to black as I remember from years ago.
Photo from the play "Two Rooms". The gaps in the EL-wire must be from the digital photo process as there were none viewing live.

 

[NJLX]

As microstar says, EL wire *can* dim. In my experience though, EL wire can produce a high-pitched whine, which changes as it dims. I'd say LED tape with some variety of PWM dimmer(DMX controlled or not) is the way to go.

 

[almorton]

The thing that sounds like a mobster is a dirt cheap microcontroller (couple of bucks). They have analogue and digital interfaces for reading potentiometers and for doing PWM. All you have to add is a MOSFET that controls the power to the tape. The code to do this is actually on the arduino website as an example of how to use them.

 

[curtis73]

The thing that sounds like a mobster is a dirt cheap microcontroller (couple of bucks). They have analogue and digital interfaces for reading potentiometers and for doing PWM. All you have to add is a MOSFET that controls the power to the tape. The code to do this is actually on the arduino website as an example of how to use them.

I had heard the name before and knew it was something in that vein. I'm one of those people who thinks Raspberry Pi is a box with 3.14 fruits in it.

 

[gafftaper]

I think I would look into classic rope lights. My Aunt has a string that's been running 24/7 outdoors for probably 10 years. They are hard to damage and they come in blue too.

 

[TimMc]

I think I would look into classic rope lights. My Aunt has a string that's been running 24/7 outdoors for probably 10 years. They are hard to damage and they come in blue too.

You're so.... incandescent!

 

[Aaron Clarke]

Food for thought, is blue LED good enough?
I've found blue LED hit and miss and feels more like black light to me (especially the cheap route) and causes me a bit of eye strain if I need to actually see something. I also think any light leak to the audience stands out like a sore thumb. After a trying of several blue LED light sources in some of our backstage areas I'm back to 25w and 40w frosted blue bulbs and a couple ropes of incandescent blue rope light and I'm happy with them and crews have not been complaining.

 

[almorton]

We fitted 10W LED floods gelled with L120 as worker blues which works really well and makes highlighter pen on the script really stand out.

 

[curtis73]

Your concerns about the temperature of the blue color have been in my brain. I currently have some LED bulbs in "pie pan" work lights back stage and they are just perfect. I need to find a spectrograph and find out what the actual wavelength range is and try to duplicate it. It is just slightly on the violet side of blue. Enough to make teeth, eyes, and highlighter glow, but not enough to be "blacklight."

My other thought is that I should just do RGBW strips. It's rare that I need reds backstage, but I do like to keep it within the basic palette of the show. If the audience is seeing really warm colors and their rods and cones get spent seeing orange on stage, they're less likely to see red bleed from backstage. I almost always just stay blue backstage and it's rarely a problem, but RGBW might be nice to have the option instead of cornering myself with blue. One strip, any color, DMX encoder, done. Yes?

 

[Malabaristo]

This has me picturing the lighting equivalent of a monitor engineer: mixing your run lights' color & intensity to track the stage scene-by-scene. Part of me likes the idea...

But yeah, RGB or RGBW tape, a matching DMX decoder, and power supply (usually separate) are all you need.