News
New Production Run of Transilluminators
02/11/2007
Occasionally, we make a run of XILS transilluminators as a special service to the museum community. Using our standard COLD-NOSE High Performance 150-watt Projector, instead of plugging in 32 fibers for a complete lighting system, we attach a special flat woven pad made out of thin, thread-like acrylic fibers. The fiber optic pad is bright, really bright, producing over 450 footlamberts. The woven pad is 9-inches x 6-inches, less than 1/16th-inch thick and is on a 25-inch tether. Altogether the transilluminator pad is 34-inches long.
The product is ideal for checking paper artifacts, looking for counterfeits or forgeries, repairing textiles, photographing watermarks, using under glass trays for washes and a host of other highly specialized tasks done in museum and other laboratories. Nothing works like it.
We manufacture fiber optic lighting, not lab equipment. Our goal is to replace damaging tracklights and fluorescent fixtures so museum artifacts do not need to be restored using a transilluminator. The pad requires a lot of hand work including surgical knots which are time consuming and difficult to tie. It is specialized work that takes special set up and training. Even though our VP of marketing spent years working as a crime scene investigator, we kind of hate making these things. We do not always have them in stock.
So here is the announcement. We just made a special run for our conservator and laboratory friends. While they last, you can buy one of these nifty lab units. Give us at 302-628-9933 to reserve yours.
Don't Be LED Down The Garden Path (Part 1)
06/05/2006
COLOR IN "WHITE" LEDs
Hearing a lot about "white" LEDs? So are we. If you've seen our annual Lightfair interview with the boss in Architectural Lighting, you know some of what is going on. If you haven't, that's what this article is all about.
Just so you know where we're going with this series, LEDs are great for a lot of things. Unfortunately, lighting art and artifacts isn't one of them. For low-voltage, intermittent use, monochromatic color (RGB or even Y), or long life, LEDs can't be beat. But they don't do so well where color rendition is important or UV is a problem. And wired together in banks, they loose a lot of their reported efficiency. People are making lots and lots of claims for LEDs right now. Lets take a look at LED lighting.
"White" LEDs work somewhat like fluorescent lights. Fluorescents pass current through a mercury vapor generating UV. The UV then excites phosphors on the inside of the fluorescent tube that in turn emit "white" light. "White" LEDs generate bright blue light (450nm) to excite the same kinds of phosphors. That is why the spectral power distribution above looks so strange. The spike is the LED true emission. The flat curve is the phosphor filling in some of the other colors.
UV free fluorescents are not possible. While more phosphor means better color, it also means less efficiency. Make the phosphor coating think enough to absorb all of the UV, and the outside layer stays dark. You don't get any light out.
For exactly the same reasons you can't make a "white" LEDs without a strong monochromatic color component (usually blue) overriding the phosphor emissions. You'll find a lot of variation among "white" LEDs in terms of color and efficiency as companies experiment with different phosphors, but you'll never find a true "white" LED. You can find information including color temperature and photographs of beams for dozens of manufacturers' "white" LEDs at
www.ledmuseum.org.
Scientists are experimenting with building RGB emitters into a single LED. That would create a tri-stimulus metamer to fake your eye into seeing "white" light. The problem so far is that each of the LEDs, red, green and blue, degrade at a different rate. The LEDs change color over their life. Engineers are talking about individual color monitors for each RGB LED. A "beta" version not yet on the market is supposed to have a cost "marginally higher" than high end HID fixtures. Who knows what that means?
So most of today's "white" LEDs have a strong blue component. Often the blue shows in splotches through the whiter phosphor emissions. Manufacturers mixing orange based "warm-white" LEDs with blue based "cool-white" LEDs advertise 3000°K to 6000°K color temperatures. Actual measurements are more like 3700°K to 8100°K. Mixing LEDs will help the overall average color temperature but it won't give you a more even beam. It makes things worse. Be aware that you are not going to have good color and then try to blend colors by maintaining long throws.
Beside making things look bad, blue is exactly the wrong color for preservation in a museum or archive. Blue light isn't reflected by the yellows and browns of parchments, faded textiles or ancient artifacts. It is absorbed. It doesn't aid vision. It increases damage. That is why the National Archives (NARA) set a 500nm cut off for light sources for the charter documents. Check the "white" LED power distribution again. Where would the 500nm cutoff fall?
As we mentioned above, LEDs are great for some applications. But where color is important, they just aren't there yet. You can literally get better color (and more efficiency) out of fluorescent or HID sources at a much lower cost. And, we wouldn't be NoUVIR if we didn't remind you that none of these sources meet IESNA guidelines for museum (or commercial) lighting by filtering all non-visible radiation. No UV, no IR: NoUVIR.
Don't Be LED Down The Garden Path (Part 2)
06/04/2006
UV AND IR IN "WHITE" LEDs
Hearing a lot about "white" LEDs? So are we. And some of what we're hearing just isn't true. Especially LED claims about UV and IR. So, lets look at some actual LED test data and separate the science from the science fiction.
We started this series with a spectral power distribution for a typical "white" LED (just the center of the graph above). Typical "white" LEDs have a blue spike at 450nm and a lower phosphor curve centered around 560nm. Phosphors, manufacturers, beams and color temperatures may vary slightly. But, the basic curves remain the same.
The problem is, lighting manufacturers tend to limit their data to the visible range. Until recently UV and IR were not considered problems. Then they either extrapolate (believe without testing) that the data continues along the same curves, or if they know better, they let you believe that the data continues along the same curves.
The fact is that it doesn't. The low points at the end of the visible range are not the tail ends of the LED spectral outputs, they are simply low points (valleys) in the data. You need to know that significant UV and IR emissions continue past the data points most manufacturers show you.
All LEDs emit UV. The graph above is what the full spectral power distribution of a "white" LED looks like. Notice that the UV output matches the intensity of the LED visible light output. Notice, too, that the IR output matches that of a steam radiator.
To be fair, we found no measurable UV in the long wave 300-380nm range. That this is the only UV that most museum quality UV meters measure may just be a coincidence. Regardless, there is big difference between no long wave UV and no UV at all. (That's why the government sets UVB filtering standards for sunglasses.)
The photo above shows a UVX Radiometer using a 200nm-300nm head (UVB and UVC) in the actual testing of a major brand "white" LED luminaire. The meter shows a UV output of 3.8"W/cm2 for their "cool white" LEDS. The spectral power distribution from the manufacturerﾒs website shows peak output for this LED to be roughly the same intensity, 3.7"W/ cm2. Their "warm white" LEDs show even worse results, a peak output of 1.9"W/cm2 and a short wave UV output of 2.9"W/cm2. The bottom line is that these fixtures put out as much UV as they do blue light.
All LEDs also emit IR. As a matter of fact, heat dissipation is a major factor in LED design and LED life. While manufacturers may say stupid things like, "all thermal energy is conducted through the housing and not radiated in the beam," the fact is that these LED luminaires stabilize around 50°F above ambient temperature. The whole unit radiates IR. No object that radiates heat can be considered IR free.
Despite some manufacturer claims, LED sources are not UV and IR free. Their high short wave UV output makes them particularly dangerous for art and artifacts. Without significant secondary UV filtering LEDs are not acceptable light sources for fugitive or fragile materials and do not meet IESNA guidelines for museum lighting.
Don't Be LED Down The Garden Path (Part 3)
06/03/2006
EFFICIENCY AND LIFE EXPECTANCY OF "WHITE" LEDs
Hearing a lot about "white" LEDs? So are we. We hear things like "50,000-hour life" and "huge energy savings." That sounds terrific. But, let's see the numbers!
LEDs are current sensitive. An LED circuit needs to regulate current to the LED as the LED's temperature changes. It needs to do this for each LED individually. You can't have one LED burning out and taking out the whole array like a string of old style Christmas lights. You dim LEDs by limiting current, not voltage. A rheostat won't do it. All this requires very sophisticated, and not terribly efficient circuitry.
The major supplier of the "white" LED equipment we tested listed an efficacy of 6.4 to 7.7 lumens per watt for their linear LED unit. Other products went as high as 10.7 lumens per watt in the "cool white" range (8100°K). Nevertheless, a standard 60 watt GE warm white light bulb has an efficacy of 14 lumens per watt. The "best" LED unit we tested was only 75 percent as efficient as a plain frosted electric light bulb and the worst had 45 percent the efficiency. Considering that an electric light bulb is 94 percent IR and only about 5 percent visible light, these are not very impressive numbers.
Regular electric lamp life is measured by the average age (under absolutely ideal conditions) at which they fail. We know that overdriving LEDs can make them brighter, but it significantly shortens their life. We also know that LEDs tend to change color and loose intensity as they age. While LEDs advertise extremely long life numbers, one begins to wonder just how useful those final years of life truly will be.
The chart above along with reported research by RPI shows that under the good conditions LEDs can be expected to loose 40 percent of their intensity in the first 4000 hours. Under overdrive conditions the graph seems to indicate that this loss can be as much as 90 percent. With new products coming out almost daily it will be some time before really accurate life data is available. Bear in mind simple life testing itself (running 24/7) will take eight years. We are on uncharted ground. But, it would be best not to count too heavily on extended life until test data is available.
Finally, keep a eye on LEDs. There is a tremendous amount of R&D going into LEDs and some of these hurdles may be overcome. Some problems, like the monochromatic nature of the LED itself and the significant UV output appear to be integral to the technology. For now, LEDs are perfect for signs, displays, low intensity, intermittent, low-voltage and monochromatic applications. They may be good solutions for effects, color changing applications and architectural and outdoor lighting where access is difficult. They are not appropriate where color rendition is important or in any indoor lighting applications of fugitive or fragile materials. The high UV makes them dangerous in museum and retail applications. Like any other lighting technology, LEDs are good for some applications and terrible for others. The trick is in knowing which is which. Knowing the true numbers will help.
NOUVIR U.S. CHAMBER OF COMMERCE BLUE RIBBON WINNER
05/11/2006
NoUVIR DOES IT AGAIN! NoUVIR was awarded a Blue Ribbon Award at the 2006 Access Awards for the United States Chamber of Commerce. The only Delaware company and one of just six award winners in the Northeast United States, this is a high honor indeed for a small business. Jack and Ruth Ellen traveled to Washington, DC for a gala awards presentation that included presentations by Newt Gingrich and Hillary Clinton and meetings with Thomas Donahue, President of the U.S. Chamber of Commerce and John W. Snow, Secretary of the U.S Department of the Treasury.
To date we've been:
- Delaware's Small Business Person of the Year, 2000
- One of Industry Week Magazine's 2000 top 25 growth companies
- Seaford C. of C. Small Business Person of the year, 2001
- Featured business on an episode of PBSﾒs Small Business School
- Case study in the college text, Small Business Management: An Entrepreneurial Emphasis, Longenecker, et al., 2003
- Case study in What No One Ever Tells You About Marketing Your Own Business: Real Life Advice From 101 Successful Entrepreneurs, Jan Norman, 2004
- Now a U.S. Chamber of Commerce Blue Ribbon Award Winner
Of course, Jack Miller, was involved in all of this too, right up to a personal meeting after the awards with Secretary of the Treasury, John Snow and Chamber President, Thomas Donahue. Both Secretary Snow and President Donahue were surprised to hear details about inequities in IRS policies regarding patents and capital gains earnings by small businesses. This was particularly the case with Secretary Snow as those policies directly countermand an act of congress.
With over 130 U.S. Patents, Jack has been a recognized in court 41 times as an expert on patents and product design. He has been working with the U.S. Chamber and others as an advocate for patent reform. We're hoping that the outcome of this particular award ends up being good for small businesses across the country.
PROTECTING MUSEUM EXHIBITS FROM THEIR ENVIRONMENTS (and vice versa) by Matthew Miller
05/10/2006
This book is the first truly integrated approach to the problems of: LIGHT, TEMPERATURE, HUMIDITY, POLLUTION and INFESTATION. Most resources treat these dangers as separate elements of conservation science. But they are not independent. Author Matthew Miller states, "One problem leads directly to the next. These dangers can only be dealt with effectively if they are prioritized and address in order."
Discover the relationships between these dangers and how each one adds to the next. Find out how easy it is to reduce the energy driving these reactions or use it to eliminate the problems altogether. The science is deep, the examination focused and the solutions are practical. This is valuable information, particularly for those with limited budgets.
Learn the secret of inexpensive case micro-climates. You can order this book directly from NoUVIR Research. Deluxe paperback, 153 pages, 51 illustrations, includes a full index and useful formulae. $35.00 Total. (Includes all handling fees and shipping by Priority mail or UPS Ground.)
NoUVIR excepts MasterCard or Visa. Simply e-mail an order to ruthellen@nouvir.com, send a request by fax to 302-628-9932, or give us a call at 302-628-9933 to order the book. You will never get a computer or voice mail at NoUVIR, just great service.
REFLECTED ENERGY MATCHING AS A CONSERVATION TOOL by Ruth Ellen Miller and Jack V. Miller
05/09/2006
The definitive study of fading and photochemical damage, this book adds ten years of additional research to Evaluating Fading Characteristics of Light Sources and Fading of Fugitive Colors By Museum Light Sources. Reflected Energy Matching defines the physical interactions of light and matter and shows actual ISO blue wool fading tests to evaluate common museum lighting sources.
It then shows how it is possible to tune exhibit light to practically eliminate fading and photochemical damage. Actual test results again using ISO blue wool fade test materials and fugitive water color dyes in a number of colors document 60 percent to 90+ percent reductions in fading. Simply eliminating non-visible radiation from light sources can extend exhibit life by 5 times. Proper Reflected Energy Matching can increase this to 70 to 100 times.
Reflected Energy Matching Theory has been called the most important advance in conservation science of the century. Learn the details in this simple, easy to understand but profound book. Protect your collection from photochemical damage while actually increasing visibility with the principles in this book.
Deluxe paperback. Contains actual color prints of fading tests in five colors so that you can evaluate the data. If you only read one conservation book in your career, read this one! $30.00 TOTAL (includes all handling fees and shipping by Priority Mail or UPS Ground)
NoUVIR excepts MasterCard or Visa. To order, simply e-mail an order to ruthellen@nouvir.com, send a request by fax to 302-628-9932, or give us a call at 302-628-9933. You will never get a computer or voice mail at NoUVIR, just great service.