Light Conservation at the National Museum of the USAF Published Aug. 16, 2023 By Ty Greenlees Dayton, OH -- Recent visitors to the National Museum of the United States Air Force have noticed changes to the lighting in some of our exhibits, as well as a temporary gallery closure. Beginning in May, the museum closed the Early Years Gallery for a scheduled renovation of the overhead lighting system to upgrade the aging system, as well as address the findings of a recent exhibit lighting survey. The temporary closure of the Early Years Gallery was a disappointment for museum visitors, but the improvements are vital to the health and longevity of the museum’s priceless artifacts. The new lighting will both improve the conditions for artifacts but also improve the visitor’s experience when touring the gallery. "This new system will allow us to make lighting adjustments throughout the gallery, isolating individual aircraft and artifacts instead of one overhead wash of light," said Will Haas, chief of the museum's Exhibits Division. "The new lighting system will allow us to create drama and visibility in the areas where we want drama and visibility while also being able to decrease levels for sensitive or rare objects." Throughout the past 100 years the museum, on behalf of the Department of the Air Force’s Heritage Program, has amassed a collection of more than 133,000 artifacts and 2,900 aircraft related to Air Force and Space Force history. About 8% of that collection is on public display in the museum along with more than 350 aerospace vehicles. A large portion of the collection is on loan worldwide to other military museums, civilian museums and veterans’ organizations and cities. The ongoing improvement of museum galleries and exhibits allows us to continue to preserve and share the history of the US Air Force and US Space Force with the public. Visitors can expect to see continued adjustments to both the overall lighting of the galleries as well as exhibit-specific lighting, all in an effort to install more modern features that improve the visitor’s experience and better preserve these historic artifacts. The museum has had a variety of light in the past including fiber optic, fluorescent tubes, halogen, and incandescent lighting. There was a big shift to LEDs in the late 2000s, according to Jennifer Myers, the museums objects conservator. “When LEDs first came on the market the museum world really embraced this new technology. LEDs promised to emit very little heat or UV which has historically caused visible damage to museum artifacts. Over time we have learned that while LEDs cause less damage than other types of lighting, they can still cause damage due to high levels of visible light.” “Visible light can not only cause fading, discoloration, and yellowing, but also embrittlement of a variety of materials. While the type of lighting is very important to preservation, the duration of exposure, distance from the light source, and what the artifacts are made of play a key role in how they deteriorate.” Myers said. “By controlling how much light an artifact is exposed to, we can extend its life.” Haas explains it this way,” Number one, light damage is permanent. And it’s irreversible. It’s also cumulative, and so, the fact that for many years we had too much light in certain areas and not in others, resulted in some undesirable damage.” “The damage we’re seeing in the galleries was gradual over a number of years, which is why it wasn’t obvious that damage was occurring.” Myers added. “As soon as we realized what was happening in the galleries our light designer Kelsey Gallagher and I took steps throughout the entire museum to ensure the preservation of the artifacts on display.” An immediate solution was to shut down lighting in affected display cases to slow the progression of light damage. While this temporary reduction of lighting within certain exhibits may be an inconvenience to visitors, it is necessary to ensure that the artifacts are protected for generations to come. “How do you balance the need to save an object in pristine condition versus exhibition where a visitor can comfortably view it?” said Sarah Gilcrease, museum textile conservator. “Part of light conservation is all in this balancing act.” They have also implemented new procedures to more quickly identify damage in its early stages. “One of the steps we’re taking to try and mitigate light damage is going to be the ‘blue wool’ standard in cases. These blue wool test strips contain specific light sensitive dyes that are indicators of light damage that can be read and visually compared to an unexposed blue wool test strip,” said Gilcrease. A newly formed Collections Division volunteer corps will help monitor the blue wool test strips. The group will notify the Collections Division about the light conservation or other issues they observe. “This is going to be a huge help in monitoring the galleries.” Myers said. Additional long-term measures are also being implemented. Motion sensors have been installed on select display cases that are not in heavily traveled exhibits. The lights turn on when visitors approach and turn off when the visitors pass, cutting down light exposure to the artifacts. New LED lights that have adjustable intensity and color value are now in use as well. There is also a shift to the use of lighting technology in new display cases. The use of lighting installed inside cases will be assessed on a case by case basis, when necessary by the age or material of the artifacts, interior lighting will be omitted. Instead, the tops of the cases now feature white translucent panels that allow diffused light to reach the artifacts. This is where the expertise of museum Exhibits Light Designer Kelsey Gallagher comes into play. She has taken a key role in researching new techniques for theatrical style lighting to intentionally position lighting throughout the galleries, known as sculpting or painting. This technique allows for more drama or sensitivity depending on the needs of the exhibit. “Currently, visitor feedback tells us people believe the galleries are dark. Visitors are going from a bright outside environment into darker gallery spaces. It takes the healthy young eye on average 10 minutes to adjust to the level of light around them. Light level is often a matter of perception. “That’s something we want to improve upon. Redirecting the light from the objects to the text, or lighting-from-behind text panels so our eyes can adjust.” “Lighting and conservation are a moving targets. We are constantly working with new information, new technology, and newer materials,” Gallagher said. “Since the artifacts vary greatly throughout our history, the way they react to light, and how they have already changed on a chemical level is something we are all learning. This effort is one that does not have a finish line, but instead is more of a lifebuoy. As we continue this project our goal is to stay ahead of the findings and continue to float atop the goals of longevity and conservation.” “Eventually, every exhibit case and all the lighting throughout the museum will be adjusted. But we can’t do it overnight. It will take a couple of years,” said Myers. “At the moment some cases in the galleries are darker, and we ask the visitors to be patient as we work to improve the environment for the collection. We’re entrusted with the care of these important artifacts, and we take that duty very seriously.” “I had a professor once who said, “Conservators are the only people arrogant enough to think that they can stop time,” said Gilcrease, “but, that is literally our job,” Gilcrease said with a laugh to think: freeze, stay right there! And that is our job, to stop time.” While conservators cannot actually stop time, their efforts to slow the affects of light damage to the museum’s artifacts can prevent further deterioration and assure that the Air Force story is represented through a top quality historical collection that is displayed for generations to come.