By Sophia Chen August 10, 2015
Photo / Image Source: Unsplash
Why do museums want LEDs? It’s not just about cost—it makes preserving paintings easier, too.
UNDER MUSEUM LIGHTS, the vibrant yellows in Vincent van Gogh’s iconic sunflower paintings have muddied over time. The yellow pigment van Gogh used—lead chromate, more popularly known as chrome yellow—darkens so noticeably with light exposure that artists eventually switched to different yellow pigments entirely.
But it’s not just Van Gogh’s yellows that suffer: Light will make most paints change color. So when a masterpiece is on display, curators, lighting designers, and engineers work together in order to keep the lights low and the painting pretty at the same time. Recently, to reduce energy costs, art museums have been shifting to using energy-efficient LEDs. But the switch isn't just about cost—it can make preserving paintings easier, too.
Scientists can identify which colors of light are most damaging to paintings—for Van Gogh’s sunflowers, it’s blue and UV light. Actually, UV is bad for all paintings, and you can’t see it, so it contributes nothing to your experience of the painting’s prettiness. “You don’t want any UV in your light source, ever,” says Aurelien David, a scientist who works for Soraa, an LED development company. “You would ruin the art, and for no good reason.”
In the past, to protect their paintings, museums put UV filters over their inefficient incandescent bulbs. But LEDs make it simpler: They don’t give off UV at all. (It’s one of the reasons why they’re so efficient, too.)
Right now, museums want their replacement LEDs to light a painting like their old incandescent lights. But LEDs have to be specifically engineered to look lose their unnatural fluorescent-like glare. Here’s how it works: You start off with a single-color LED—say, purple. (Single-color LEDs are simpler to make than multi-color.) On top of that purple LED is a collection of metals called a phosphor. The different metals in the phosphor will absorb the purple light, emitting other colors that combine to make white light. Engineers can play with the composition of the phosphor to achieve the look that a museum wants.
The resulting light from the LED looks pretty close to the traditional halogen lamps that museums used to use. “The difference isn’t perceptible,” says Jens Stenger, a conservationist scientist at Yale University. “If you don’t have a direct comparison, it’s hard to recognize the difference.
But light is still light, so even with its perks, LEDs still damage paintings. So that’s when engineers and designers put their heads together. In recent years, lighting designers have been controlling the direction of the light, accenting a fragile artwork rather than uniformly lighting an entire room. An art lover doesn’t need to see the faces of other museumgoers to appreciate a piece, so by dimming the overall gallery and directing light, the artwork gets less exposure, and thus, less damage. Engineers have also been working on designing LEDs whose direction can be controlled more precisely.
The potential of LEDs goes beyond mere protection. Engineers can also adjust the warmth of LED light—it’s possible, for example, to make an LED that looks like sunlight without all the energy-wasting and paint-destroying UV. But museums haven’t tapped into these features yet. “Right now people are fairly conservative,” David says. His company’s clients have mostly just wanted LEDs that mimic the look of their old incandescent lights.
But the LEDs’ tunability makes room for more creativity: Artists can play around with more varieties of lighting, or maybe a museum can put on a light show that makes a blue and black dress look white and gold. So whether you’re admiring a classic painting or foisting a contemporary art experience upon an old-school uncle—an LED makes the cultural experience better.
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