LED 101 by Eric Bartnes
Published in Professional Lighting and Production Magazine

Good morning class. Grab your coffee, get your feet off the coffee table and let’s start learning. Today’s subject is LED lighting and how you can use it to your best advantage. (LED’s rule, use them. The next 3000 words are just filler!) Our side of the entertainment industry is incredibly wasteful of both natural and man-made resources. If you look at an outdoor venue when you shut down the generator and drive away, you will see the ground littered with garbage, mostly non-recyclable. The way of the future for the lighting and visuals departments is to cut our power consumption down significantly. If you can adjust your power needs down to what is available at the venue, you can avoid bringing in a generator, which aside from making Mother Nature much happier, will save your producer money. In a tight power situation, use as many LED’s as you can, and save the power for the moving lights, video or audio. By designing earth friendly, you can feel better about yourself and the state of our industry.

First things first, LED stands for Light Emitting Diode. Get used to them because they are here to stay, and we are only going to get better, cheaper products every day. There is currently a gap in most rental companies inventories when it comes to low priced LED fixtures. Specifically in the décor market, if you could replace a single colour Par floor light with a multi coloured LED that draws ¼ of the power, why wouldn’t you?

If you look at the evolution of light, it started with the creation of light on the first day. (Read up on it in the Bible, page 1). Firelight was humans first artificial light source, then we learned how to make candles and from there we can thank Edison, (with a shout out to Tesla!) for the invention of the vacuum-sealed filament bulb. Over the next hundred years or so, we added to our lighting toolbox the fluorescent, CFL (Compact Fluorescent Lamp), the HID (High Intensity Discharge) and now we have the LED. Some people are under the impression that LED’s will replace all conventional lighting. I’d bet those same people also thought that about way about each new advance in light source. If you think this way, let me ask you if we still use candles. With all the tools at my disposal, I still think candles look best on a woman. LED’s are just another tool in your design kit, they won’t replace conventional lighting in the near future, but you can use them in many ways to do things that conventional lights cannot do.

Henry Joseph Round initially discovered LED’s in 1907. He was working on a radio detection method for marine vessels when he discovered the physical effects of electroluminescence. The discovery was pretty much forgotten about for many years until the first introduction of a Red LED in 1962. By 1971, other LED colours were introduced with an increased output and effectiveness. 1n 1993, the dark blue we all love was ready to go and scientists had discovered the conditions needed to create white light. By 1995 we had our first LED in white. The LED bulb is a highly robust unit, significantly less fragile than traditional bulbs. With most LED bulbs rated between 50,000 and 80,000 hours of full intensity continuous usage, the chance of having to replace the LED bulb over the product lifetime is minimal.

There are many reasons to go with an LED fixture: Very low power consumption, no heat, lower weight, millions of colours and virtually maintenance free.

The low power draw has many advantages over conventional fixtures. With LED, you can replace the power draw of a 1000-watt par can with between 10 and 30 fixtures (depending on the manufacturer) for the same or less power consumption. 24 x 1K pars on the back line will draw close to 70 amps of 3 phase 208V when you crack them all to full. (If that’s how you roll!) 24 LED fixtures could draw around 1 or 2 x 15 amp 120Volt wall plug. Less power = Less copper = Less weight.

On last years Michelle Wright Christmas Tour, I replaced my usual moving light rig with a package of Microh LED bars, a Catalyst, a Console, a hockey bag of fabric and a pair of 50” plasmas. With my lights, dust machine and video, I needed only 3 wall plugs. Over 22 shows, we would have paid an average of $200 per show for an electrician for tie in and to disconnect around midnight, so that saved the boss close to $4500.





On top of the electrical savings, the rig weighed considerably less. I shipped it from Toronto to Regina where we started our tour. The entire visuals rig, less the Plasma’s that sit in Michelle’s living room, weighed in at 960 lbs and packed tight on one skid. Remember, that’s lights, cable, tools, computers and soft goods.

Now that good olde par can generally had one gel in the frame, unless you feel like complicating your life with scrollers. With an LED fixture, that one light now has millions of colour possibilities. Having said that, I seem to get 7 colours with slight variations. Including the RGB, I also get yellow, turquoise, magenta and a pretty lame white when all three are added together. Now the white may be dirty looking, but when you punch it over another colour, it really lights up the stage. As it is a digital light source, there is no ramp up on a dimmer, so they snap to full instantly on a bump button, or they can seamlessly fade from one colour to another so slowly that it’s hard to see the transition happening.

Heat generated by our trusty stage lamps has always been an issue, be it burning your fingers on the cap, burning the backdrop or just the sheer amount of HVAC required to air condition a venue when you have your rig running. As our physics class taught us, heat rises, so all that heat from the rig is now up on the ceiling of the venue, and it has to go somewhere. As LED fixtures produce very low heat for their high output, this alleviates many heat issues we face with conventional lighting. Although we love the look of an incandescent bulb, the shear amount of wasted energy should give you pause for thought. Almost 96% of the energy consumed by an incandescent bulb is lost due to heat. Only about 4% of the energy consumed makes the light, the rest is “wasted” by generating heat, which we then need to remove from the fixture, and remove from the venue. Heat is also the greatest enemy of the LED bulb, sort of like it’s only predator. (Aside from that one crew type we all know that can break your gear without cracking a sweat) The higher the light output in an LED fixture, the more sensitive the LED’s are to heat. The brighter the bulb, the more the manufacturers have to come up with ways to dissipate the heat, as it can negatively affect lamp life. The heat management issue and the luminous efficiency is a quest for LED manufacturers. All over the world, labs are working on new and brighter LED’s, which require better cooling, and to improve the light output while lowering power consumption.

There are many ways to measure light, most somewhat confusing to us practical types. For me, it’s helpful to use the lumens per watt measurement to compare the efficiency of the style of lamp. For example, an HPL 750 has an efficacy of 29 lumens per watt, a CFL is around 45-60, and an MSR 575 is 85. Red LED’s can be up to 46, Green is up to almost 80, Blue hovers around 26 and White LED’s these days can reach up to 98 lumens per watt. The highest rated light source is the low-pressure sodium, which can reach up to 200 lumens per watt. Now before you go all wild and start using low-pressure sodium, remember that the Color Rendering Index (CRI) is zero. In layman’s terms, that light looks like crap. It is used where power efficiency is everything, and rendering of colour is not important, like in streetlights and lighting public egress points. The above numbers are open to argument, go ahead and correct me.

Refresh rate is another important factor in your decision on which LED fixture to use. The camera is very sensitive to shifting light levels, much more than the human eye is. Some fixtures have a low refresh rate, and the camera will really pick up a flicker on your stage. In a live stage environment, this is not really a concern, as the fades look pretty seamless to me.
There are two main types of fixtures available on the market: Fixtures than utilize individual Red, Green, Blue (and sometimes Amber and/or White), and the single diffuser with 3 x RGB LED’s on one small pc board. One advantage to this type of fixture is that shadows are not multi coloured like they are with RGB fixtures.

When using fixtures with just RGB, I find the pastels weak and the light does not look good on the face. But for saturated colours, beams thru the haze, set dressing and colour effects, as a tool it can’t be beat. Fixtures with the additional Amber and White LED bulbs offer much better colour mixing and superior pastels colours with a higher CRI index.

One of the first LED fixtures to gain mass usage was the Colour Blast by Color Kinetics. It is a very bright fixture, with a small size that can be hung in any position. It is widely available globally in several variations. This is a bright fixture with low weight, and can be hung on any angle very easily. These fixtures cannot daisy chain data, and all need a home run back to a PSU. With 50’ being the recommended run, you need to put PSU units all around the rig, as opposed to sticking them all in dimmer beach.
Color Block by Spectrum Manufacturing was one of the next fixtures out of the gate and has gained a world wide base of users. It is a small robust unit, with each block having 4 clusters of RGB. One of the advantages is full control of all pixels so you can bitmap images if you put enough Color Blocks together. Other nice features are the way they attach to each other, making for a fast installation and the PSU has many addressing options with great on board effects. I generally patch the PSU as conventional channels and utilize the on board effects more than the effects engine of my console. Spectrum also has several new LED products including the Color Punch, Color Split and the Color Web, a flexible mesh with 2 different LED pitch resolutions, 250 mm and 125 mm.

The President of Spectrum is Jean-Francois Canuel, a long time lighting industry veteran and designer of some of the products we use today. He cautions designers to carefully look at issues like CRI and to be wary of all the marketing material out there. JF pointed me to the US Government’s Department of Energy web site which has a ongoing program called CALiPER. They are taking the new digital lights and putting them to the test. The results are worth looking into, as there is a gap between advertised performance and real world efficacy.
http://www.netl.doe.gov/ssl/comm_testing.htm

JF also has a good analogy about RGB and audio. Bass is blue, midrange is green and high end is red. When you add all three, we are supposed to see white, or the frequency range of 20-20K that we hear. What we get is an icky white, or just crappy sound with parts of the spectrum missing. You get only a portion of the bass, mid’s and highs. Just as the sound would be missing some of the range, the light is also missing parts of the visible spectrum. The new white and amber LED fixtures trick the eye into soft pastels, but they will not reflect all colours evenly from costumes and set pieces.
SGM has a very nice LED fixture in the Palco line of lights. They are a very well made and bright as all get out. The newest units have remote pan and tilt capabilities as well as adjustable colour temperature. This is an expensive fixture, but worth it for many uses. It is a killer set and backdrop light, although it moves slowly, real slow.

The Chinese manufacturers have been playing a lot of catch up lately by producing better made fixtures at an attractive price point. (Full disclosure, I own a fistful of Microh LEB Bars) You really have to do your research on which product to buy, as over a product lifecycle, the manufacturer may use different LED’s from different sources on product runs. This means if you buy LED fixtures in separate batches a year apart, you may end up with colours that are slightly different.

Some manufacturers like American DJ, Chauvet and Elation have been charging into the market with some really excellent new product, priced for entry-level users. I like the Colorado fixture from Chauvet. It throws a nice tight circle of light and looks pretty cool onstage. Recently I went to an informal shoot out between a Martin Mac 600 NT and the Elation Impression, the first robust moving LED fixture. The Impression is well made, lightweight and draws significantly less power than a 208 Volt moving light. The light output kept up to the Mac 600, the saturated colours looked fantastic, but it still suffered in the whites where the random strobe on a 600 killed it. Having said that, the strobes in all the other colours were pretty devastating.

Osram/Sylvania has been a global leader in the manufacturing of LED bulbs. I spent some time with Steve Duff who told me about their huge manufacturing and research arms that are always testing and refining their products. Osram is co-coordinating a new LED project with the EU called CombOLED. OLED (Organic Light Emitting Diode) is a new style of LED being manufactured, specifically where flat diffused light is needed. This new technology is being worked on in the labs and you should expect to see this new style of light available to you in a couple of years, or sooner as they work on lowering the manufacturing costs.

With Phillips buying out Color Kinetics, and the associated patents they owned, Phillips has become a major player in the LED market. I expect new products to be hitting our shelves, as they are a global player with massive research budgets.

I have many great LED success stories, and I’d like to review a project we did where LED lighting saved the day. The Bowmanville Zoo is Canada’s oldest privately owned zoo, located around 45 minutes west of Toronto. Mike Hackenburger is the Zoo Keeper and has been keen to retrofit his theatre lighting for years. The venue has a 200 Amp single-phase services, which is shared with the building. We tossed around the idea of adding 3 phase power to add more lights, but the cost of the copper and the install was prohibitive. Mike had a legacy light rig in the theatre, an AMX CD80 bolted to the wall, an NSI console with AMX converter and a whack of old fresnels and pars in the air. We decided to purchase 12 Microh LED bars and remove as much conventional as we could. What we ended up with was a 25’ tall set that was now properly lit, 10 fresnels lighting the ring and about 40 old lights and pile of cable left on the ground. Where we used to draw around 125 Amp, our average load is now down to 20 Amp per leg running full tilt. The client is ecstatic with the new look, and will reap the rewards over the years with lower power bills, a great looking stage and significantly lower maintenance.

So as you can see, the advantages to LED stage lighting are numerous, only limited by your budget and your imagination. These are exiting times for the stage lighting industry, with new technologies and products coming every day. It is in your best interest to research these new products, as your recommendations are what rental companies listen to when they are considering new purchases. If your supplier doesn’t change with the times, how can you? Well, one way is to call me up and rent mine!

Sources
http://www.osram.com/osram_com/Professionals/index.html
http://www.netl.doe.gov/ssl/comm_testing.htm
PLSN magazine / Richard Cadena
http://www.ledsmagazine.com/main
Life on the road.