Welcome ladies and gentlemen. I'm Bob Davis with the Pacific Northwest National Laboratory, and I'd like to welcome you to today's webcast titled, LEDs, Can They Perform in a Performing Arts Building? The webinar's brought to you by the US Department of Energy's solid state lighting program.

We're very happy to have as our speakers today Naomi Miller of the Pacific Northwest National Laboratory, and Stanley Kaye of the University of Florida. Naomi Johnson Miller is an engineer in the solid state lighting program of Pacific Northwest National Lab focusing on lighting quality, energy efficiency, sustainability, and the acceleration of LED technology deployment.

Previously, she was principal of Naomi Miller Lighting Design in Troy, New York. She is a fellow of the Illuminating Engineering Society of North America, and of the International Association of Lighting Designers. She holds a Bachelor's of Art and Design Degree from Massachusetts Institute of Technology, and a Master's degree in Lighting from Rensselaer Polytechnic Institute.

Stanley Kaye is head of the Graduate Lighting Design program at the University of Florida in Gainesville, where he has taught since 1999. His research focuses on the use of automated lighting technology and traditional theater and dance forms. In the past 30 years, he has designed over 150 drama, musical, and architectural productions. And he's taught theatrical and architectural lighting design at various universities.

He's earned a BFA from Brooklyn College, City University of New York, and an MFA from the University of Hawaii, Manoa. And he's a member of the United Scenic Artists, 829, the International Association of Lighting Designers, and the Illuminating Engineering Society of North America. Naomi, please begin the session.

Thank you, Bob. And before I begin, I have to tell you that one of my chief complaints about webinars is that they get a little boring. And the main reason is that the presenters are staring at their screens, not staring at real human beings.

So in order to counteract the boring part, Stan has agreed to wear a French beret, so that he looks very artsy fartsy. And I am wearing a cat in the hat hat. So if you get bored, just imagine us speaking to you with our hats. And that will help alleviate some of the tedium. Let us proceed.

So we'll be as entertaining as we can.

We have a program through the Department of Energy call Gateway. And Gateway's intent is to look at real installations of LEDs, and basically explore where they work, where they don't work, how they could work better, and teach how to use them better, so that we can get better penetration of LEDs into the marketplace, and ultimately save more energy sooner. So that's the reason for Gateway.

And a few years ago, Stan and I got together and said, you know what, performing arts buildings have a lot of unusual spaces and unique needs that we should look at here. Because those, even though they sound like unique needs, these are things that a lot of different
applications use.
So the University of Florida has the Nadine McGuire Theater and Dance Pavilion, which is 46,000 square feet of dance studios, acting studios, several theaters, a scene shop and classrooms. Like all performing arts building, it is busy day and night.

Lots of classes going on during the day, lots of rehearsals, lots of tech work at night, evening classes-- so it's not a typical college classroom. It sometimes is a space that is occupied 24 hours a day. The University of Florida facility folks wanted to try out LEDs to see how much energy they could save, and whether these are going to be problematic, or whether they were going to be products they really wanted to use across the campus.

Their utility rates are about $0.10 a kilowatt hour, which is a little bit lower than the average. Why did we care about a performing arts building? Number 1, these are large volume teaching spaces, open ceilings, high ceilings.

And as a result, generally these spaces are lit with higher lumen output luminaires than you get in a typical classroom. So it's not your standard 2 by 4 recessed troffers necessarily, or standard recessed down lights. They're usually higher in lumen output. So that was a challenge, especially when we started this work.

The second thing is you all know that it's really important when you're looking at a dance performance, or an acting performance on stage that you as the audience can't see the performers or appreciate their body movements unless you can see them. And that translates to vertical footcandles, or vertical illuminance on the bodies and faces so that you could follow their gestures, and also appreciate the emotion and the movement that goes into their work.

There are campuses all over the country with performing arts spaces. Now performing arts buildings are full of a lot of arty people, and very tech savvy people. And they have extremely high standards for color quality. And when you're talking about using dimming in a theatrical space, or a dance space, it is super important that you have [INAUDIBLE] with lighting that can be dimmed down to off.

You've all heard the term black out. So dimming performance is extremely important. So this is a very [AUDIO OUT] space for LEDs. Because we've all known that LEDs in the past have had some color challenges and dimming challenges. Another reason to look at this is that traditionally halogen theatrical lights are a whopping 21 lumens per watt maximum.

Compare that to LEDs that are often these days 60, 80, 100, 120 lumens per watt, and you can see a big difference. When you put a blue filter in front of a theatrical fixture that's halogen, that blue gel is often about 5% transmission. So you apply 5% to 21 lumens per watt, you're down to 1 to 2 lumens per watt from that luminaire. So you can see the efficiency is pretty doggone low.

Well, can we do similar things with LED? That was the question we wanted to answer in the theaters. PNNL helped identify four spaces, lots of theatrical productions, for evaluations. Four spaces that were changed out from their installed lighting to LED lighting.

And those four spaces were monitored with energy equipment that was able to collect power and energy data. Now remember, the difference between power and energy-- energy is power times time. So these devices were able to report back over time how much power was drawn, and that gave us energy data.

The four spaces were the scene shop, the acting studio, makeup mirrors in the dressing rooms, dance studio, and then a dance performance space which took place in the same dance studio. Stan—

Yeah, so the scene shop is a highly activated space. And it went through various retrofits to create energy efficiency, but it didn't really consider safety. It was very, very poorly maintained given all the equipment on the ground level. So getting up to them was difficult.

We had serious concerns about danger to students, bodily injury. You have young, inexperienced people who have never touched a power tool in their lives trying to build things under a real deadline. And so it was a very bad situation.

So we really want to make an improvement here. You have very, very low light levels, two or three foot-candles at the spinning blade. And so we looked at LED options. Can you go to the next slide, please?

So we made that change. We evaluated fixtures to be sure we were not going get a stroboscopic effect affecting the spinning blades. We had a pretty high density pack of these linear fixtures that Naomi will talk about. We also removed a 24/7 set of emergency circuits that were keeping lights on all the time.

And we gave them three circuits of dimming, and we weren't sure whether or not the users would end up using them. But in fact they did. As activity ramps up, they would raise the light level, depending upon what they were doing. As activity ramped down, they actually dimmed the lights.

This is also somewhat color critical because things get painted in this environment, and then go out onstage. So the color match was important. So all of these features were the things that we kept in mind as we went through the redesign of this room.

In the lower right hand corner, you can see one of the plots that came from the energy monitoring. The blue line is the before condition. The before condition was a lot of fluorescent fixtures that have been installed for decades. And a lot of those fixtures had erroneously been wired to emergency circuits.

So they were on 24 hours a day. So you can see that even at 2 o'clock in the morning, you have about a third of the lights, or almost half of other lights, burning. Which was, of course, a big energy sink. And then you can see the ramp up during the day. And then it gets shut off, or shut down to the emergency level at 5:00 PM.

When the LEDs were installed, they were re-circuited so that there was no light on emergency circuits. So you see that the fixtures are off in the middle of the night, appropriately. Then the operators turn them on to full output during the day. And they actually do shut them off when they go to dinner. When students are using the space in the evening, they often dim them down to lower levels.

So this was a very effective reduction in energy. And even though the light levels went from something like 60 lux to 600 plus lux, we dropped the energy use by 18%. So we reduced energy even though the light levels in many cases tripled, or even increased more than three times.

This is a plot, or a chart, just showing the before and after fixtures that were installed. And if you want to look at details of how many fixtures are installed and how much power they're drawing, it's all there. Basically, the before condition was using 1.2 watts per square foot. And the after condition was only a small reduction of 1.1, approximately, watts per square foot.

But even with that reduction, the light levels were so much higher. Stan, back to you on the acting studio.

Yeah, so this is a 40 foot by 40 foot acting studio, but it does more than that. So in terms of usages, it's a multi-use studio. It's got acting classes in the morning. We teach fight choreography in there, with people doing sword work and rapier work. Or there might be rehearsals for productions that are going to happen on the larger stages in our facility. And then there are actually small scale performances in this space.

So we have a black ceiling. There's a pipe grid for theatrical fixtures, grey acoustical panels, and a black floor. So there's little surface reflection. The original design, which had a pretty extensive, high density pack of recessed can lights, was reduced in the value engineering, which created an inadequate amount of light.

The users affectionately gave it the nickname the cave, and it sure did feel like that. Over the years we did Band-Aid fixes from things we had laying around the building, like theatrical cyc lights, R40 type strip lights, put compact fluorescents in them, had incandescent flood lights, just sort of hobble by.

It really was an embarrassment in terms of the way it was. So we went ahead and we then tried to increase the vertical foot-candles, as we talked about, by reducing glare. So our approach was to use these wallwashers bouncing off the little bit of reflected walls we had.

This is a positive effect in that the room felt much bigger. The spaciousness was achieved. They were also on dimming circuits. And then there's an array of LED recessed cans in the center of the room, which can be both raise and lowered. And they make extensive use of that.

So the indirect-- in a sense, what we bought in the efficiency allowed us to make the primary light in the room indirect using the wall services as reflectors, and that actually increased quality at the same time that we were increasing efficiency. So we took that, captured that savings. And then used it for a more indirect solution.

And the pictures, I think, tell the story quite well. And the professors who work in there have all made extensive use, depending upon the scene or the mood of what's going on, they will-- if I walk by in between classes and the lights are low, I come back and there's a rapier class with swords and they're way up high.

I might watch small scene or a duet piece, and the lights are dim. So again, our personnel are light sensitive. So they are making use of those controls.

In the bottom right hand corner, you can see another one of the meter plots. The blue line is the before conditions, with the metal halide fixtures and the cyc lights that were installed as a remedy. And then the red line is the after conditions. And you'd have to be blind not to be able to see that there's a big reduction in power use there.

And the main reason is when the metal halide fixtures were installed, instructors became terrified of accidentally shutting off the lights because it took 10 minutes to re-strike after they extinguished the lights in the space. So everybody learned very quickly not to turn lights off.

Now that they're LEDs that don't have a re-strike issue, the instructors are much more likely to shut lights off or dim them down at any given time. Here is a comparison of the old and the new. Metal halide down lights versus LED down lights-- and then CFL cyc lights that were installed as the remedy, versus some LED wallwashers.

If you look at power density at the bottom, the old system was using about 1.25 watts per square foot. And the new system is-- tada-- 0.55 watts per square foot. So we cut the energy down to less than half. But still got higher light levels overall. Stan.

So this is one of our largest studios. We call it the G6 dance studio-- a beautiful space. And again, it serves multiple purposes. It does have daylight penetration. It includes blackout shades that are motorized, as well as theatrical drapery that can be pulled.

Morning is classes, afternoon's rehearsals, and at times we set up performances in here with seating as well. And you'll see the theatrical piece that we did, the dance piece was done in this space. So again, the original design-- this is back in 2004, 2005-- tungsten lamps can lights, which we would've been changing them every week, I think, if that’s what stayed.

Due to the unfortunate VE process, they were removed. And some of these warehouse floodlights were installed. Again, they were metal halide and had the warm up time problem. They provided very poor color rendering, produced quite a bit of glare.

And you can see in the photograph, sometimes the dancers are doing floor work where they're laying on their back, looking up into the ceiling. And that was really pretty uncomfortable for that. So we needed to find another solution.

And what we ended up with were these edge-lit panels. And it was a very simple swap out. And these panels provide an outstanding even distribution, and particularly vertically. If you notice the walls in the photographs, they're just illuminated from floor to ceilings.

Dancers love space. They're space hogs, frankly. And it made their room-- when we first turned them on, they were just flabbergasted of how big the room felt, even with all windows. They felt like, wow, the room's opened up. And fantastic vertical illumination-- so when the dancers are looking at themselves in the mirror or at each other, they can really see each other.

The glare-- unless they are right directly below that quarter inch panel looking up into the LED, there is very, very, little glare when they're doing the floor work, which was a big thing for us to achieve. Again, the vertical foot-candles were outstanding.

We did give them dimming controls. And Naomi will talk about the power savings. We also attempted to capture the beautiful Florida daylight that comes into those lovely windows with a photo sensor, but that didn't pan out as well as we would have liked. And Naomi will dig into the details on that for you.

And the dancers actually do make use of the dimming controls in this room. They did self-report that they felt that the overall light level in the room was lower. And I think that's probably due to the fact that maybe we didn't put as many fixtures as maybe we could have. Maybe our calculations were slightly off.

But they counter that by saying, but the distribution is so much more even. And we can see what's important so much better that they didn't mind that.

Now looking at the bottom right hand corner, another plot of power use over the course of the day. We look at these knowing that there were daylight dimming sensors in the ceiling that should've dimmed down the lights when there was daylight available. Well, you can look at that red line, series of lines, and there's no reduction, no dimming kind of reduction that happens there.

So we scratched our heads, and ultimately went back to try to figure out what the problem was. But there were tremendous energy savings. Here is the original light, the metal halide low bay fixtures, and then the edgelit LED after condition, taking the energy down from 0.71 watts per square foot, to half, 0.35 watts per square foot.

Now the daylight dimming control, when we look at them there was no dimming. So we looked into this, crawled up inside fixtures, or inside daylight sensors, and found out, guess what? The daylight sensors had never been installed properly or commissioned.

And you know what? These things have been active for months, and nobody knew that they weren't working. The only way we knew that they weren't working is that we had this energy monitoring in place. So once we realized nothing was happening, we went back and the manufacturer's representative came in, commissioned the controls.

We're assuming that there's now daylight dimming in place. But it's a real issue. When you've got photosensors, it's so important to do the proper commissioning. But sometimes it's difficult because the instructions are a bear and a half, frankly. Stan.

So another space that we chose to do which we knew was sort of a critical space are the dressing rooms. And Now these rooms aren't used every day. They're used when there are rehearsals and performances, primarily.

And this is the traditional way they're set up, with incandescent lamps around the mirrors. And we thought, could an LED perform well and be acceptable.

These incandescent lamps create a lot of heat. You got actors in their hair dryers, you name it. It gets really hot in these spaces. So anyway we could reduce the heat was important. But we had to maintain this critical color because they're doing their makeup application in this room.

When they move from the dressing room to the stage, if we don't have some kind of baseline consistency, we get big surprises on stage, which we don't want. So we evaluated a whole host of LED products and tried different things.

Some things we noticed was that we're getting a lot more light than we were getting before. And we we're also getting quite a bit of glare. So we installed dimmers, which were easily done on the makeup mirrors. But one word of caution, be careful to evaluate the dimmer and the lamp, and that they are compatible. Because we did achieve quite a bit of buzz, which was sort of problematic.

Of course, bringing the level down on the LED lamp did not initiate a color shift, a color spectrum shift in the lamp, which was great. We weren't sure how the makeup people were going to respond to that. In fact, they reported that they were happy.

They were finding that the consistency from applying the makeup under the LED source and then moving to stage, there was less of a variance than in the past. And I think is also due to the high CRI of the LED.

And power savings are extraordinary-- A 72% reduction. So we feel pretty comfortable with the way these worked out. And Naomi will talk about the consumption and the lamp on the next slide.

Looking at the energy use over time, there was a 72% reduction in energy use, so power times time. And the great thing is that there were dimmers on each individual mirror so that that reduced the energy even further.

This is the bulb that was in there before. It's a 130 volts, 40 watt bulb. The bulb that went in as a quote "40 watt replacement" actually produced a lot more light. Because 130 volt incandescent bulb is effectively dimmed when you put it on a 120 volt circuit.

So it was only producing about 200 lumens. The LED bulb is producing 450. So that's not a surprise that they felt brighter when you put them in, even though they were a 40 watt equivalent bulb. But look at the power density reduction.

When you turn on all of those incandescent bulbs in that room, 12.66 watts per square foot, just from the makeup lighting. And that dropped to 3 watts per square foot. And in Florida, the heat from those puppies make an enormous difference.

Now let's look at all four of the spaces-- dance studio, scene shop, dressing room, acting studio. We've talked about the reduction here. So you can see that in every single case there were reduction, even though there were light increases in places like the scene shop and the acting studio, which is pretty good testimonial.

If you look at the average lighting energy density, which takes the energy use over time into account, the energy use for different occupancy, this allows you to compare different buildings that are different sizes and different numbers of hours of use, for example, and the four spaces that we examined in the performing arts building we're at about 1.5 kilowatt hours per square foot per year.

Compare that to the average lighting energy density in university buildings of 4. So it's a pretty big energy improvement. Stan, I think—

Yes. So we also wanted to test, and we were excited to test, the theatrical fixtures between tungsten and LED. And the difficulty, of course, was to do it in an actual performance. Because we wanted to get both metrics, and we also wanted to get qualitative information from the audience.

So fortunately we have very generous dance faculty who agreed to put together a dance piece. And we have a fall and spring undergraduate showcase production, which uses a very small sort of lighting rig. And we thought, well, maybe we could do that.

And one of our faculty suggested doing a famous piece of the dancer Loie Fuller at the turn of the century who was both a choreographer dancer and sort of a lighting designer in her own right. She worked with the Lumiere brothers on colorizing early black and white film. And so it's based around a piece she did using the piece of parachute cloth.

And the cloth becomes a sculptural moving canvas. And so what we did is we agreed to do that piece. They were able to get a costume for it, and another adjunct faculty member did the dancing. And we put an undergraduate lighting designer on the project, explained to them what we were trying to do.

And we did the piece twice. Once in the fall, and that's what you're looking at here with halogen. The piece ended up with seven cues. The first one being a white light, which was tungsten from overhead.

All the colored light came from the sides, which is more traditional in dance. And we asked the designer to work with saturated red, green, blue, and maybe pale pink and white, and create the cues that he thought were appropriate for the production. And so we can get the measurements, and then we also did surveys with the audience each time.

And this was controlled by a typical DMX-512 console, which worked great for the tungsten, but not so easy when we're dealing with the LED. So again, we did this twice. And in the spring, we used the LEDs. And we use two different manufacturers for both the electronic theater control's seven color system, and the Phillips brand Selecon unit four color system, both from each side.

And we were really quite stunned with the results. I would say controlling the LED from an older DMX controller that did not have an easy way to interface with the color choices was cumbersome. But nevertheless, we overcame that.

There's a slide of the two fixtures. Things that we learned-- all these fixtures have standby power. And they have standby power at different amounts of consumption. So we looked at that. 27 watts on the Phillips and 5 watts on the ETC.

They both provided fantastic light. And you'll see the video in a minute, and unfortunately you won't hear the sound. But the results were, from our eye, and you'll see the chromaticity diagrams, we really couldn't tell the difference. Now we did not do skin tone work on this. We excluded that from this particular piece.

It would've been a more complicated test to keep everything consistent. Although we have some really great products coming out now that do skin tone remarkably well. So there's the fixtures, and there's the consumption. I'll let Naomi pick up on that.

Yeah, it's difficult to compare the new LED theatrical fixtures with the older LED-- or the older halogen fixtures because the lumen output is different. Obviously, the color capabilities are quite different, and the power is so different.

But we learned that even though these are very different instruments, they were wonderful tools to add to the lighting designer's pallet in the theater. I'm going to show the side by side video of the dance performance. I'm going to start right here. And unfortunately, we do not have the capability of broadcasting the sound.

So the piece, the orchestral piece, or string piece that accompanies this is really beautiful. So I strongly recommend you go online, find the link, and watch it on the YouTube channel. But you'll see on the left is the halogen performance, and on the right is LED.

The top lighting that you're seeing right now, that's all done with halogen top lights. But as soon as the side lights kick in with the second cue, you're starting to see the color. Again, on the left it's filtered halogen. On the right, it is the LED. Stan, you might want to—

You'll see at the end when Naomi compares the consumption-- Now this student is a young designer. I would say the light levels in general, for those of you who are theatrical people, were quite low. It's a small space, and young designers have really good eyes, so sometimes they don't turn them up as bright as you might like. So it's quite subdued.

But yet the audience proximity was very, very close. And remarkably, we did surveys with both audiences and asked very pointed questions about their response. We really couldn't find, in the qualitative work, much of a difference. But the consumption was dramatic.

We'll also talk about, in lessons learned, the control side, and consistency of color between manufacturers, and how these things are being made, and being able to access it. I know there's some good work being done in that world, which we're thankful for.

We handed out the same survey in the fall to the audience as we handed out in the spring. The audience knew there was something different. They didn't know that exactly what had changed. But interestingly enough, the observations from the audience were virtually identical in the fall and in the spring under the two light sources.

But the LED was using somewhere between 50% to 90% less power than the halogen was. In the report, the full report, it goes through each of the seven cues, plus the blackout at the end, to show you what the spectral power distribution looks like between the halogen and the LED.

What we did was to put a color meter in the place of the dancer and measure the color distribution, the spectral power distribution, from the left and from the right that the color that would be impinging on her silk costume. And those are shown on all of these different cues.

So you can see snapshots of the cues, and then you could look at the SPDs of the halogen and of the LEDs. It's actually teaching us that it's very difficult to look at spectral power distribution and really interpret what the color was going to be. For one thing, in the halogen scenes you can see that there's a lot more long wavelength red being emitted, up near 700 nanometers and higher.

And that is probably an artifact of the fact that gels were designed to allow some heat to be transmitted so that the gel would last longer. It wouldn't burn up as quickly. As a consequence, there's a lot of red emission in the halogen scenes, or cues, that you don't see in the LED cues, even though the visual images are very, very similar. Stan, do you want to take over?

Yeah, so we'll just go through these real quickly. I have a couple points. And I'm sure there will be questions and maybe we'll have your answers. So we learned that SPDs can't tell you everything. You've got to use your eyes, obviously. But from the audience's perspective, it made very little difference.

Shadow and pattern were similar. They looked great on spinning silk. The skin tones were not an issue for us in this one because we did not focus on that in this study. Let's go to the next slide, please.


Here's the power consumption that you just talked about it. You can just see it dramatically. Visually, we didn't see a difference, but consumption-wise, it was just tremendous.

But take a look at those short, red bars, even in the blackout scene, last cue, you can see those short, red bars. That is the standby power. So even when there is no power being delivered to the halogen in the blackout cue, there is still power being drawn by the LED system because those LED fixtures, theatrical instruments, have to have some standby power in order to receive instructions.

So we said we know that there's still a large initial cost difference between the LED and the halogen instruments. So the ROI alone can't justify the change based on energy savings for most projects. For new projects, we suggest considering a mix of LED and halogen instruments, depending upon your client or whatever product you might be doing.

For existing theaters, we can certainly see you replacing old instruments. There are ways to sort of retrofit the light engine and still salvage lenses and other housings of the fixture. On some projects, operational savings might justify-- they use long hours, hard to reach, frequent color replacement, and so on.

The students, in terms of the next generation of designers, really enjoy using the LEDs when the color was easy to select through their control systems. We loved not having to go change gels. We loved being able to change color slowly over time.

Some of the newer consoles allow you to draw a path, so you can avoid going to certain colors as you fade is terrific, and in particular making a change as you creating on the fly for the arts can be tried in this color. And there's nobody getting on a ladder to do that. So people understand that these are some of the advantages of the LED situation.

What's the next slide? Again, I'll just reiterate we did not do the skin tone. They're shy in the red range, but that wasn't a problem for us. And we know that there are fixtures out there that are boosting the red in the LEDs to get good skin tone, or using dynamic whites. But this piece used rich, saturated colors.

And again, it performed as well as gel halogen. The audiences perceived no difference between the two performances. And neither did people with critical eyes, as well. All felt the same way. From a controlled perspective, the older lighting control that we had on this was a problem, in terms of being able to make that work. A newer console with a color picker makes it so much easier.

So we're looking forward to the standardization of color picking. And there's been some nice articles on out there about how to make some standardizations for color picking between manufacturers and how these LEDs are better in theatrical fixtures.

Smooth dimming, particularly in this case, because our designer really didn't bring things up very bright. This was his choice. So you start to see them sort of pop on. That's an issue that's being dealt with in terms of software. And the stepping question of intensities, which can be a distraction.

I guess the big takeaway is all these theatrical LED instruments are not equal. So we have to evaluate them and decide what's best for that user and that project.

We're in the home stretch here, yay. So let’s go through some lessons learned. LEDs can be an excellent solution in high ceiling spaces. So you don't need to worry about LEDs being under-powered anymore. And compared to metal halide where you have the old pain-in-the-neck re-strike problem, they're a big improvement.

Also there's less noise from them compared to old magnetically ballasted metal halide buzzing noisy fixtures. Mockups are really important. When you have clients who can't really visualize what lighting is going to look like, and especially with colors that they're not familiar with, color of light, mockups really help improve comfort with this upcoming change.

And for lighting designers too, you all know that cut sheets can't tell you anything about glare. They can't tell you much about flicker. They often can't tell you enough about color. So mockups are completely invaluable.

Manual dimmers-- we didn't know if they would be used that much, but ultimately they have been. They've been very widely embraced by the teaching staff. And that allows the teacher to have much more flexibility in their classrooms, which they appreciate.

This is an important one. Uniformity of work plane and vertical illuminance is important in classrooms and studios because uniformity of light on the work plane is related to vertical illuminance. If you have lumpy lighting, like is shown in this photograph on the right, you are not going to get vertical illuminance on bodies and faces of somebody who's standing between the lumps.

Now if you have overlapping beams of light, that's when you get much better vertical illuminance. So although these are not directly related, very uniform work plane illuminances do very often translate to better vertical illuminances, which is of course very important in performing arts spaces.

I might mention that we mocked up everything before we made a final choice on fixtures. And we did reject some fixtures as well.

And then photosensors-- watch out. Because photo sensors and dimming drivers, they're a great idea, but only if they are commissioned properly. Vampire power, that's the standby power that you are not always aware of a fixture drawing, should be taken into account. And if you're doing theatrical productions with LED fixtures, be sure to shut off all of the fixtures completely after performance so they don't continue to idle and draw standby power continuously.

It will probably save the life of the drivers as well.

The theatrical lighting power reductions are tremendous-- 50% to 90% compared to halogen with filtered color gels. And if you use LED products that have a broadband white LED, that can improve rendering of skin tones on stage. LEDs can reduce maintenance if they indeed last 25, 35, 50,000 hours.

It is so much better because it's such a pain in the neck to get a piece of equipment in here to reach up to fixtures to change out light bulbs or LED strips. So with longer life, that is indeed going to mean that this lighting system is going to produce higher light levels for a longer period of time. Look at that, Stan. We're done.

Bob, are there any pesky questions out there?

Oh, you might say that. First, of all thanks Naomi and Stan, very much. Really fascinating stuff. It seems like each space could have been a full study in and of itself. We have dozens of questions. And just for those of you participating today, so you know, there's more than 500 people participating today. So I've got dozens of questions.

Let me start with a few just clarifying ones. And I guess I'll say to those you participating, there were some questions that got into details about the products that were used, and some of the specific measurements. Those things are all in the report that we'll refer you to.

So I'm going to try to pull things that are just things that aren't in the report that can offer some clarification. And Stan and Naomi, I get a little bit of an echo, so if your volume is up on your computers you might want to turn that down. Stan, I guess I'll start with you.

A big picture question I thought was a good one, someone says the designs of the spaces didn't look particularly well laid out in the before conditions. So the question was if the lighting that was there had been OK, would you have considered LED retrofit lamps instead of replacing the fixtures? Or did you feel like new luminaires would have been the way to go regardless?

Great question. I think in the dance-- in the large acting studio, yes. We lost the distribution in the VE. So had we not all those sockets, basically, I think-- but I say yes to that. We could have done that in that room.

However, what I discovered, and I thought was quite fascinating, is the power of the vertical illuminance when we could get by using surfaces in the room as reflectors, rather than from above, when we always get raccoon eyes. We need to see people's eyes.

And we don't really want to see the shadow from the nose down on the lips. So when that light comes in vertically without producing glare, that was such a fantastic-- I think that went over so well for people.

So yes, we could have done a retrofit by just changing out the lamps. But then still all you light is still coming from directly overhead. That's great if you're doing desks. But we're not looking at a horizontal plane. We're looking at vertical services and people.

So I think the answer is yes, but what we gained in lighting quality in this new design was such a welcome thing. Same thing in the dance studio. We could just take out those-- I think there were eight, Naomi, metal halide floods in that dance studio. But using those blades just changed the entire nature of the specs.

So yes, we could have done that. But I think this ended up being a better solution.

OK. Great, thanks.

The dancers didn't feel like they had to wear baseball caps to be comfortable afterwards.

And a related big picture question, and I'll direct this one to Naomi to start. When you look at the options, the question is, in lieu of LEDs, did you consider long life fluorescent T8s at any point, since they can have life ratings of 50,000 hours plus at this point.

Well, the point of the demonstration was to explore LEDs, so we really were focusing on LEDs. But you know what? If LEDs didn't make sense, we would definitely have looked at long life fluorescents, especially if we could look at a retrofit. Unfortunately, the lighting systems that were there really didn't lend themselves to a retrofit.

It really made more sense to do a wholesale change of light fixture. And if you're making a wholesale change of light fixture, then it makes a lot of sense to look very carefully at LEDs. But that's an excellent question. If indeed fluorescent had been the better solution, we definitely would have gone with long life fluorescents.

Stan, a couple of-- we have lots of questions on color that I'll get to in a minute. But there's a couple just quick, clarifying questions that might help. Vacancy sensors-- did you consider, or are there vacancy sensors used in different spaces?

We did consider that, but we didn't do it. I don't know for sure whether that would've been a good decision. But the building is so peculiar and activated. For example, in that acting studio sometimes they're doing a scene and an actor was using the door to the hallway as an entrance or an exit. And if we got lights going on and off, that defeats the purpose.

So in hallways that might have made sense. Maybe in the dressing rooms that might have made sense. But most of those rooms, the way our routine, the way people use the building-- there is stage management that turns off lights at the end of the day. So there's sort of that activity.

And the amount of savings in between when the room might be empty for 10 minutes, the hassle that might be caused by occupancy sensors, I don't know. We didn't really think about it too much. I'm suspicious about whether they would've been the right solution for those spaces.

I can add to that. In the dressing rooms, it definitely would've made sense. Because frequently I would walk into the dressing room and find that the lights were blazing even though nobody was in there. But in the scene shop, occupancy sensors, although originally considered, were not installed for safety reasons.

Because the last thing you need is somebody to be working in a corner on a power tool and have the lights drop out. So for safety reasons, there were no occupancy sensors installed there.

I agree. The dressing room would've made sense.

And I guess Naomi, since you brought up safety, there were a few questions about the scene shop and safety. One was just a clarification. Since you mentioned the fixtures being removed from the emergency circuit, the question was you can reduce safety concerns through that. I assume there were still some emergency lighting in the space?

Yes, that's right. There was dedicated emergency lighting.

And then the question regarding the safety there is what tools were used in order to check flicker during mock ups to verify that there was no flicker or stroboscopic effect on the moving machinery and power tools?

Naomi will have to confirm for me, but I believe the two primary ones that we looked at were the table saw and the radial arm pull over saw.

Yes. And we also use the waving finger test.


So just the visual ones-- I guess the question was did you measure flicker, or was it just evaluating on those devices to be sure there was nothing visible?

We did not-- I don't think we measured, did we?

We did not measure flicker. We did not have a meter of any kind. But we, well, Naomi Miller was on the site, and she's—

Highly tuned flicker sensitive person.

Exactly. she's a very expensive meter. I did not detect any. But also the other people who were in the shop with us looking at a power saw did not see any evidence of stroboscopic effect.

I should mention one thing about the light level in the scene shop. The university has standards for their rooms. And in that room, we exceeded that standard. And we felt it was appropriate. At one point we really put in too much light in here. And of course, because of the shift from what it was to what it became, the occupants were like, oh my god. This is so much light. And they now love it.

So we have to sometimes come up against what the university says is the power density-- but this is what's going on. Or in our costume shop, where we have people sewing black thread on black fabric for six hours, the university standard is not necessarily appropriate.

Got you.

They really targeted 75 foot-candles or 750 lux in the scene shop.

Is that what we landed at?

Well, we have another five or six minutes. And there have been, as you can imagine in these applications, lots of questions coming in on color. So let me read several of these, and have you guys talk some about the experiences with color. So comments like, we've been concerned about the discontinuous color spectrum of LEDs. How did you evaluate this?

The second question-- on the makeup mirror, was there no reaction to the spectral distribution of the LEDs? Typically these are spiky in certain wavelengths, regardless of overall CRI. Or has there been improvement in the technology? And then other questions relating color spectrum of LED compared to traditional quartz lighting for makeup and scene painting.

How did you evaluate that? How did that come out for makeup and costume color, for scene and set design? Questions about comparing the colors under the LED to conventional sources, one question, Stan, specifically asked when you paint your sets are you using some fluorescent or halogen sources, even now while you're painting?

Or are you really doing it all under LED? So lots of questions in that regard about color spectrum, and how that was evaluated, and how you feel about the results.

Where should we begin? There's a lot packed into that.

Well, I can talk briefly about the spectrum. If the CRI of the lighting that went into the scene shop, for example, was in the 90s. So if you look at the spectrum, it's a quite continuous spectrum, not spiky at all. And the same thing of the lights in the dressing room. That was a 93 CRI lamp. And the spectrum is quite continuous and gorgeous. So Stan, do you want to talk—

Yeah. I would say in one of the questions it was mentioned the spiked CRI, I guess the question is are we seeing differences that are enough to be concerning between painting, or makeup, or costumes under the LED sources to our stage. And it's a really great question.

So far, so good. We haven't had any surprises, remarkably so. Now our stage has a combination. For example, we also paint in the wings sometimes. And so the wings have a ceramic metal halide at 3,200 Kelvins. On stage, we still got tungsten work light. And in the scene shop, we've got these new LEDs.

I guess it depends upon how critical your client is. In our scenario, it has not been significant enough that we got a completely different result than we were expecting, either in make up, costume, prop, or the scenery. So far so good. But we were quite worried and paid a lot attention to what we chose.

So we really did quite a mockup evaluation before we said, yes, that fixture with that lamp we think will work.

And I think I can add that the spectra were less spiky in every single space than the light that was in there originally-- a metal halide, or even fluorescents, for example. The only exception would be in the dressing rooms where, of course, you had an incandescent lamp in there originally.

That was the one we were most concerned about. Could the LED really make it? Because that's where its most critical. In some ways, it's really critical. And we were absolutely flabbergasted when the makeup faculty said, we like it better. We're getting a more accurate result.

And then a related question, Naomi, that you could answer is was the analysis of color measured in the field, or was it simply based on manufacturer's ratings and visual analysis?

No, it was measured. We had a Konica Minolta color meter that was able to measure spectral power distributions, and then translate the SPDs into various color metrics.

And related to metrics, a couple questions about-- obviously, we're talking a lot about CRI. Some folks are raising the point that the CRI metric has come under some question. There's been things like the color quality scale and other proposals for color. And so just some general questions about where you see color metrics as relating to this type of application, and if you know of any new things coming in terms of color metrics.

Well, yes. We know of the IES work. There is a technical memoranda number 30 that proposes some changes to color metrics using two metrics. One is a metric for fidelity. And the other is a metric for the gamut area represented by a light source compared to a reference source. So that is, I believe, under consideration right now by the IES board.

And I think that could improve our ability to communicate in color, if those metrics are adopted.

Right. And it's our understanding that those are in final balloting, as Naomi mentioned, with the IES board of directors. And in coming months, we should have those accepted and adopted. I think I'll ask just one or two more. We are at the 11 o'clock Pacific time, and it's time to wrap things up.

I had a couple more real quick things that I thought would help to bring it to a close. And for those of you that participated, I think this was a historic event. I don't think a DOE webinar has ever shown a dance video before. And so I just got a couple questions about the dance that I thought we would close with.

Stan, probably for you-- the question, is a recommendation of a mix of halogen and LED theatrical fixtures-- is that based strictly on budget? In other words, would you consider all LED, or was it considered important to maintain some halogen lighting for the performance?

It's a really great question. There's new stuff coming out every day. In some of the work that I do off campus, we do installation work. If we're throwing light a long distance, and I've got to hit a face, I'm still tungsten. But in the backbone controls, we're setting things up so that eventually the entire system can move to LED.

So if it's lighting a backdrop, or a floor, or scenery, we're really comfortable with the LED. We're still a guarded on the facial stuff. So in terms of the fixture selection, we're still doing hybrids. On the other hand, in terms of budget, on a big project to do a full LED complement in our building would be a big project.

There's going to be some sticker shock right now to take everything to LED. In a small project, if we’re outfitting in small space with 40 or 50 fixtures, I might go all the way. Because the sticker shop is not going to be so bad. And could we get the quality that we need? Perhaps.

So I think we're in that, and we're really experiencing-- to use the buzz from the disruption is-- it's now hit the fan. But we are disruptive. So we're thinking it depends upon the project and what you're using. We just opened a space with, I think, 500 circuits. And a third of it is still halogen, the front light. But everything overhead is LED.

But the distribution system can handle both. So we can dim an LED. We can dim a tungsten source. And we can power an LED driver either way. And that's probably a good transitional strategy for a large space.

In small spaces with some of the new-- as Naomi mentioned-- broadband LED for facial stuff-- and you've got a small complement. It's not going to break your budget. Why not go all LED? You're saving on all kinds of good ways on a project. So I think it's sort of project-dependent at this point and difficult to make a generalization.

OK, that's great. Thanks. Well, listen. There's lots more questions. But we are close to five minutes past our time. So I think I will wrap it up there. Let me remind those of you who participated that the slides will be available to you. They'll be posted on the DOE website. You'll get a message to that effect. The full report as well as a brief summary on the project are also on the Department of Energy website.

If you have a question you really would love an answer to, I see that Naomi and Stan were either kind enough or foolish enough to have their emails on the last slide that's on your screen right now. They both are very busy people, so no promises. But if you had a question you really hoped to get answered, and we weren't able to get to it, you can feel free to email that directly to them.

We really appreciate your participation in the webcast today, brought to you by the US Department of Energy Solid State Lighting Program. You may all now disconnect. Thank you.

Thank you, everyone.