Advice and help with building history capacity.
The Minnesota Historical Society’s Local History Services helps Minnesotans preserve and share their history. This blog is a resource of best practices on the wide variety of museum, preservation, conservation, funding, and non-profit management topics. We’re here to help.
Sustainable Museum Lighting
Museums becoming more climate-friendly is increasingly important in the field, because the effects of climate change pose a huge threat to collections. It may seem counterintuitive to pair collections care with environmentalism, but when it comes to museum lighting they really go hand in hand. Almost every action you take to reduce energy consumption from lighting will also help you to preserve the light-sensitive items in your collection. On top of that, any action you take that results in lower electricity bills means more money you can spend on other aspects of collections care, like archival boxes and padded hangers!
I recently attended an interesting webinar about environmental sustainability and museum lighting presented by David Saunders and hosted by the Icon Environmental Sustainability Network. He said that although the biggest energy consumer in most museums is the HVAC system, museum lighting represents a sizable chunk of electricity use. In his talk, David Saunders broke down sustainable museum lighting into five actions.
- Switch to LEDs
- Increased use of daylight
- Reduce light levels
- Shorter display times
- Better time management
From left to right: incandescent, fluorescent, and LED light bulbs. Photo by Megan Narvey.
Switch to LEDs
Switching to LEDs has an immediate impact on electricity consumption because they are by far the most energy efficient type of light bulb; in large part because they are so efficient at converting electricity into light rather than heat (cough cough incandescents). Because LEDs have a longer life than incandescent and fluorescent bulbs, there is also a reduction in the use of raw materials.
LED lights emit little to no UV light, which is a huge benefit for the preservation of light-sensitive collections. So LEDs are a great lighting choice for many reasons: energy efficiency, lower long-term financial burden, less maintenance, and they’re better for collections.
The Field Museum. Photo by Peter Miller licensed by CC BY-NC-ND 2.0
Increased use of daylight
This option might surprise many museum professionals! The argument here is that daylight is a free energy source, so it is completely environmentally friendly. The problem is that it’s difficult to control. The brightness, color, and direction of daylight varies depending on the time of day, the time of year, and clouds!
Direct sunlight will quickly damage light sensitive objects, even with UV filtration. Therefore, you need control systems like shades, blinds, curtains or baffles; and you might need to change their position throughout the day. A really cool solution to this problem is the use of electrochromic glass (also known as “smart glass”), which darkens or clears automatically depending on the amount of sunlight hitting it.
Reduce light levels
It’s important to limit the amount of light in museum display areas because light can damage many types of collection items. Lower light levels also benefit the environment! But there is only so much you can do to lower light levels before your collection becomes inaccessible because you can’t see it. It’s possible to create a space with very low light levels that is still functional - for example by featuring individual objects with spotlights.
The use of dimmer switches is a simple way to increase your control over light levels. The sweet spot between preservation and visibility is 50 lux for highly light sensitive materials, and 200 lux for moderately light sensitive materials. Lux is a unit for measuring the amount of light in a square meter, and can be quantified using a light meter like this.
Gallery view by John Dalton licensed by CC BY-NC-ND 2.0
Shorter display times
One way to achieve shorter display times that will benefit both the collection and the environment, without resulting in reduced access, is to use manual, timed or automated lights that respond to visitors. You can install proximity sensors that turn on the lights in an area when they sense movement, ensuring that the lights are off when nobody is in the room. Shorter display times can also be accomplished with an object case where the visitor presses a button to activate lights to view the contents for a set period of time.
Better time management
The final option can best be summed up by the old joke about dads running around the house turning off all the lights in unoccupied rooms. Ensuring that you turn the lights off in storage when you’re not working there, and turning the lights off when the museum is closed, can have a big impact.
If you’re interested in learning more about environmental sustainability in museums, check out these organizations:
Museums and Climate Change Network
AAM - Environmental Sustainability
Sustainable Museums
Sustainability in Conservation
Coalition of Museums for Climate Justice
Learn more about light as an agent of deterioration at the Canadian Conservation Institute.
To see more of David Saunders' work on museum lighting:
Podcast: David Saunders on Museum Conservation and Lighting
Book: Museum Lighting - A Guide for Conservators and Curators