Low pressure sodium lighting
June 9, 2011 2:58 PM   Subscribe

Indoor monochromatic light

I was at an art exhibition recently (Olafur Eliasson) that used a number of what I believe were low pressure sodium vapor lamps to turn everything greyscale. I would like to replicate this effect at home. First, are there any more consumer-grade, maybe LED lights that have a similarly narrow spectrum? I've been able to find the low-sodium bulbs online, but I haven't been able to find sockets for them. Any instructions out there for wiring such a thing? Basically, I'm less concerned with actually using the same kind of bulb (although it would be nice if there were a way) and more interested in the monochromatic effect.
posted by mike_bling to Home & Garden (10 answers total)
For info and LPS (low pressure sodium) supplies check your local hydroponic grow shop.

Non-white LEDs have very narrow spectra.

Experience with the monochromatic effect? For a while, I was watching videos on old green or amber monochrome displays. This user easily accustomed to seeing black-and-green or black-and-amber as black-and-white, but after a while I stopped doing this because after a movie, I noticed how the monochromatic light created a strong, peculiar after-image effect, shifting real-world colors in an odd way, which I found a little frightening (even though it wore off).
posted by Rash at 4:10 PM on June 9, 2011

Unfortunately, the lighting industry has invested bucketloads of money in preventing exactly the effect you describe.

Have you looked into stage lighting? I believe they achieve a monochromatic appearance by putting narrow-pass filters in front of a broad-spectrum lamp. For home use, you would want to optimize for longer life, lower power consumption and less waste heat, even at the expense of brightness. So a dichroic filter would work better than an absorptive one, and you're better off putting the filter in front of an ordinary lamp. Proper stage lighting is so bright that the electrical bill would be exorbitant and you might even have a fire hazard.
posted by d. z. wang at 4:11 PM on June 9, 2011

I'm not sure the effect you describe requires pure monochromatic light - also, of the gas discharge tubes, sodium is kind of unique in how few lines it has - hydrogen is all over the place.

In terms of cheap to play with, single color LEDs are probably a good place to start.

LEDs are like guppies and will take eat everything you give them until they pop, so you need a diode in the circuit. Basically, you wire them battery, LED, Resistor and back to the battery. Don't get the clever idea to put a bunch of LEDs in parallel after a single diode because what can happen is one of your LEDs fails, so now all the others are getting extra current so another fails and now they're all getting extra extra current so.....

Also, diodes only allow power to flow one way, so if it doesn't light, turn the battery around.

This LED array calculator will probably tell you what you need to know. If it confuses you, it's far from unique - poke around until you find one that explains things to your satisfaction.

At any given moment there are roughly 52 billion Ebay auctions for superbright LED variety packs from China, so, while you may have to wait for the shipping, they're out there relatively cheap.
posted by Kid Charlemagne at 5:12 PM on June 9, 2011 [1 favorite]

Most stage lighting is either plain old incandescent or metal halide discharge (both broad spectrum) with filters to create the coloured effect you see. If you want to experiment with the filters you can buy sheets of lighting gel (from gelatin, though there is now none in the material) at any theatre supply store or the like. Companies that make it are primarily Lee and Rosco, they publish specs that show what wavelengths are absorbed/transmitted etc. This will be a lot cheaper than experimenting with dichroic glass.

As for low pressure sodium, you need a particular ballast to drive a particular lamp, so you don't want a socket, you want a complete fixture that matches the lamp you want to use. This could be expensive.

Sorry, this is a quick type up on my phone (from bed!) MeMail me if you have questions, I spent over ten years as a full time lighging tech and am still involved in gallery/museum lighting.
posted by deadwax at 7:14 AM on June 10, 2011

One thing to note regarding gels, some of the colours with lower transmissiveness (right word? Probably not) pass very little light indeed. Lee 181/congo blue -every newby ld's favourite colour - passes only around 2% of the spectrum of a halogen lamp. That's part of the reason some stage lighging is so grunty, it also means you won't see much if you stick it in front of a 60 watt desk lamp.
posted by deadwax at 7:24 AM on June 10, 2011

What is wrong with my phone. Lighting. Not lighging.
posted by deadwax at 7:25 AM on June 10, 2011

Back when I was a kid, my brother and I were unable to play UNO while camping because the yellow bug light that my parents used, washed out the color difference between the green and blue cards. Well, he could tell the difference (age 10) but I (age 6) couldn't figure it out. Either that, or he just told me I was playing the wrong cards to be mean, and I believed him.

Now they come in CFL as well as incandescent versions.
posted by aimedwander at 7:58 AM on June 10, 2011

If you mean grey scale monochromatic, it isn't a possibility (since white is on that spectrum and white is all colors). But color is very perceptual, of course. You could probably fake it best with yellowish brown lighting which we sort of mentally associate with sepia toned photographs. The trick is getting a light source with a narrow spectrum as everyone said. I don't think you can mix colors to get the effect you want since mixed colors will promptly bounce off things and split back into some colors.

Another trick: keep the lighting dim. In low light our eyes uses the rods more than the cones which results in monochromatic vision. Once your eyes adjust even in dim white light, you might see some pretty darn grey-scale vision.
posted by chairface at 1:02 PM on June 10, 2011

I just noticed when I was talking about LEDs, I said you had to put a diode in series with the LED - YOU HAVE TO PUT A CURRENT LIMITING RESISTOR IN THE CIRCUIT. I made this mistake at least twice up there.
posted by Kid Charlemagne at 6:05 PM on June 11, 2011

Dont know if you are still playing with this. You can use any SOX (low pressure sodium) lamp with a standard lightbulb (E26 socket). You just need a socket (like any lamp) a converter (google E27 to B22 converter) and a ballast, or voltage stabilizer, like with Fluorescent lights. I'm personally trying a WH2 (fulham) for fluorescents to do this, like this guy.


You can always get something with more stones. if you get a sodium specific ballast it can be crazy expensive, and do you need it to last forever anyway?

As for wiring, just follow the instructions from Fulham in order to wire it. It's only like 4 connections. clip the plug off something, strip the wires, wire it to the ballast, then the ballast to the socket, and you are good to go!

Shoot me a PM if you have questions. As an aside, I doubt you can find orange led that will put out the lumens you need -trust me, I tried.
posted by wuzandfuzz at 11:42 AM on March 24, 2012

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