The Low Vision Design Committee of the New Buildings Institute has release a draft of its new “Design Guidelines for the Visual Environment” for public review and comment. The intent of the guidelines is to offer assistance to design professionals and others in accommodating those with a variety of vision disorders. Click here to visit the NBI site to download the draft.
The New York times has an “I Heart LEDs” article in today’s paper that leaves out some important information about evaluating them. Here are some additional thoughts.
The government hasn’t done a very good job of publicizing or explaining that the Energy Independence and Security Act of 2007 (EISA) set minimum efficiency requirements for general use light bulbs (the act excluded decorative and colored products). The incandescent lamp that’s been around for over 100 years doesn’t meet the energy efficiency standard. Rather than re-engineer incandescent lamps, the lamp manufacturers have focused on expanding and emphasizing compact fluorescent (CFL) and light emitting diode (LED) technologies. Again, you can still purchase 40 – 100 watt decorative incandescent lamps but not A-lamps, the most common shape in use.
The easiest substitution, one that requires no thinking about rewiring, dimming, etc., is the halogen lamp. Halogen lamps are an improvement on standard incandescent lamps, and many of them meet the EISA energy efficiency requirements.
If you’re looking for higher energy efficiency, and are willing to pay a higher price up front to get it, CFL and LED lamps are available in a wide range of wattages and shapes. However, they need to be approached with caution. Both technologies can be difficult to dim, especially with older dimmers that were designed with incandescent lamps in mind, so your existing dimmers may need to be replaced. They can also produce unsatisfactory tints of white light. LEDs are especially notorious for not matching the information provided on the packaging, as demonstrated through the Department of Energy’s CALiPER program.
Here’s what to look for. Every light bulb package should have a Lighting Facts Label that looks like this.
The orange/yellow/white/blue color bar is where you’ll find information about the warmth or coolness of the light, both with an arrow on the color bar and with a number. The number is called the Color Temperature (actually the correlated color temperature) and measures the warmth or coolness in Kelvin. The important thing to know is that a lower number (2700 to 3000 K) is roughly equal to an incandescent light bulb. As the number gets higher the light gets cooler.
Warmth/coolness isn’t the only measurement of the quality of light. Another consideration is how well the light source allows us to see the colors of objects. This is called Color Rendering (Color Accuracy on the Lighting Facts Label) and is indicated by a Color Rendering Index number. Higher numbers (with a maximum of 100) indicate better color rendering, so a light with a Color Accuracy of 95 should be visibly better than one of 80.
The Color Rendering Index is not very specific, however, and is known to misrepresent LEDs. Therefore you are the best, final test of whether or not a given light bulb is appropriate. I recommend purchasing only one or two and trying them out for a few days before committing to changing over your entire house.
My other recommendation is to stick with the major manufacturers (GE, Philips, Sylvania) for most lamps that you test. These companies have a track record of product consistency and quality that many of the newer manufacturers don’t. I can almost guarantee that with an off-brand 5-pack of lamps for $10 you’ll get what you pay for and hate the results. It’s not the technology that you’ll hate, but the manufacturer’s poor execution of the technology.
I hope this helps.
Whatever you thought of Bruno Mars last night (I thought he was terrific), you have to admit that the lighting for last night’s Super Bowl Halftime Show was outstanding! And it should have been – we would have expected nothing less. The light, color, movement, and video were clear, supportive of the music and the performances (more so for Mars than for RHCP), and scaled to fill the television screen, the staging area, and the stadium. We’ll see statistics in the entertainment industry magazines next month, but there were obviously several hundred moving lights and twice as many LED lights and display panels. It was an appropriately huge rig for a huge show, and it looked great.
There’s an interesting and exciting contrast between the 12 minutes last night and the 90 minutes of Stop Making Sense by the Talking Heads, which I happen to watch on Saturday (and is available on YouTube here). What’s interesting is that this concert has all of the energy of last night’s performance, but rather than back up the music with nearly overwhelming visuals, David Byrne and Beverly Emmons, who are both credited for the lighting design, created a show in which the lighting of the first 1/3 of the concert appears to be accidental, and the rest is still so stripped down that it seems like something must be wrong, especially when compared to today’s visual smorgasbord of color, video and light on contemporary tours. I’m not knocking big tours at all, I love them, but the contrast between the two shows, and the fact that they’re each successful, is astonishing.
In the film, we open on a slightly cluttered stage with two visible worklights hanging overhead. An impossibly young Byrne walks on with a boom box and a guitar, and appears to sing Psycho Killer in little more than white worklight. Of course, the trained eye can see that there’s a lot more going on, but that’s the look they’ve created. Over the next five songs more musicians are added, and the lighting becomes somewhat more theatrical, with higher contrast and increased intensity on the performers. Yet, it’s not until the fifth song (Slippery People) that a backdrop flies in and it looks like a staged performance instead of a rehearsal in a warehouse. 20 minutes in we get our first taste of “rock” lighting – there’s finally enough haze in the air to outline some beams of light – but it still seems like there’s only one cue per song! Although I’m sure that there’s color correction used, the entire concert appears to be performed in white light. In fact, we don’t see any color until the 8th song (Making Flippy Floppy ) a full 30 minutes into the show, and that’s only on the projection screens behind the band!
I could go on, but I won’t. If you haven’t seen this movie, or haven’t seen it in a while, watch it now. Between the bold, strong, yet spare lighting and Byrne’s unique performance style, you won’t be bored. Let everyone else talk about the Super Bowl while you go see one of the best concert films ever made.
In class yesterday one of my students, thinking about a project she had recently completed, asked, “What’s the best light for a hair salon?” I’m certain she was hoping I would tell her exactly what lamp technology and/or lamp style to use. Of course, it’s not that simple.
So the class took a detour to talk about the important aspects of light in a hair salon. We narrowed it down to two critical considerations – intensity and color rendering. Intensity is important because the stylist needs to be able to see the details of a head of black hair as well as a head of blonde hair. Intensity is relatively easy to achieve, and the designer has a wide range of lamp technologies, lamp shapes, and fixture types to choose from. Finally, everyone intuitively understands how intensity affects vision. If there’s not enough light one can’t see well enough to work.
Color Rendering is more complicated. All of my students had heard of color rendering, but few of them understood its meaning or use. Color rendering is the ability of a light source to enable us to see object colors. For instance, a light source that produced no red light would do a terrible job of allowing us to judge red apples and we would say it has poor color rendering. Color rendering is measured on the Color Rendering Index (CRI) which compares the light source being tested to incandescent light (for warm light) or to daylight (for cool light). The higher the result, on a range that peaks at 100, the more a light source simulates incandescent or daylight in enabling us to see the colors of illuminated objects.
The best light source, then, is one that produces the desired intensity and has a high CRI. Of course, there’s much, much more to color rendering and to the topic of color in light. The color chapter in Designing Light is about 40 pages, and the IES DG-1 Color and Illumination looks like it will be about 100 pages. It’s critical that lighting designers understand color because it has such a strong affect on people. Color rendering is just one aspect. Color also affects things such as our impressions and perception of a space, circadian rhythms, visual acuity, and the interior designer’s color palette. Those are topics for another post.
Today I was at an LED “shootout” at the New York City office of Barbizon (special thanks to John Gebbe and Scott Hali). We were looking at products that might be used in a specific application – that of lighting an auditorium or theatre. The shootout was between 26 fixtures from 17 manufacturers, all installed at a height of 10′.
Architecturally, the designer is essentially lighting three conjoined rooms: the orchestra, where the ceiling can be 35′ high or more; the balcony, where the ceiling can range from 12′ to 25′ because of the steep slope of the seating; under the balcony, where the ceiling may range from 12′ to 18′, again because of the slope of the seating.
The first part of the challenge is to find a set of fixtures that can provide even illumination in these three spaces, each one of which has a sloped floor and therefore a varying throw distance. The second part of the challenge is for all of the fixtures to dim simultaneously. Unfortunately, I don’t think we saw success. Here’s what we saw.
First, only one manufacturer had a product line for all three possible mounting conditions – pendant, surface, and recessed. That manufacturer, though, didn’t have three beam spread and/or brightness options to meet the range of typical installation heights.
Second, LED manufacturing is maturing, but it’s not mature. That means we still don’t have strong, industry-wide standards for things like color. In many cases it was difficult to use fixtures from two or more manufacturers because the color of the light produced (visually evaluated, and measured in color temperature, peak wavelength and spectral content) clearly didn’t match.
Finally, getting fixtures from multiple manufacturers to dim simultaneously proved very difficult. Each set of installed fixtures would need its own (perhaps custom) dimming curve just to get a close match, and identical performance seemed impossible. The problem here is three-fold. First, multiple control protocols would be required. The fixtures demonstrated used line voltage dimming, three-wire dimming, 0-10v DC, and DMX protocols. That’s not a deal breaker, but it is an unfortunate complication. Second, some of the LED drivers produced unacceptable dips, flickering, or pulsing of the light as they dimmed. Third, some of the LED drivers couldn’t make a smooth transition from darkness or light, or light to darkness. We saw fixtures pop on and drop out, dim up nicely but not dim out well, and dim out well but pop on. Eventually this might be as easy as working with incandescent lamps, but not yet.
The easy lesson was that, for now, the safest choice for smooth dimming from darkness to full light is still incandescent. The color of the light from fixtures in all of the installation conditions will match, the dimming curves will be the same, and they’re easy to dim.
The complicated lesson was that it is absolutely essential to mock up the proposed lighting system, using the LEDs, drivers, control protocols, and dimming equipment that will be installed. It’s the only way to be certain that the start and end of a show, when the house lights dim down and then back up, isn’t a light show of its own.
The prediction is for a cold and snowy day in Brooklyn as my students and I return to Pratt after the winter break. This semester will be the final pass through the PowerPoint slides that will be available to instructors on Wiley’s web site. It will also be, by my count, the 20th spring teaching this material.
At this point I assume that the only people reading this blog are my students (it’s only been active for about six hours!) so let me repeat what I say at the beginning of every semester – This is for you. I know that a lighting design can have a profound impact on the way users view, experience, and interact with a space. The goal of the semester is to help you to know it, too, and to give you the vocabulary, an understanding of the tools, and a structure (actually several structures) to frame your lighting design goals. If there’s something I can do to help you with those goals, talk to me.