Light Danger

Lengthening days of June filled the Museum's halls with warm sunlight. The beams of light penetrated the many glass panes around our building to illuminate the inner architecture, as well as the various large mammals on display. Summer has been beautiful, but in the mindset of a curator, this brightness was terrible. November's rains would be much more preferable. "Why?" you may ask. Light in any form damages our specimens. Since preservation is imperative in a museum, management of our windows becomes a concern for a curator. 

Prolonged exposure to light can cause irreversible
fading to taxidermy specimens. 

Though visible light is necessary for visitors to even see displays, light otherwise does the specimens no favors. It can cause fading and degradation to the many sensitive materials in our collection. This includes leathers, prints and drawings, fur, feathers, undyed organic materials, other biological specimens, and paints. Museum exhibits are often dimly lit, not for atmospheric effect, but for safety of objects on display. Considering this museum often fills with light from our many windows, our specimens are at risk for damage. 

Recognizing the dangers of light in a museum requires a bit of understanding of light itself. Radiating from the sun are three different ranges of wavelengths we are concerned about: infrared, visible, and ultraviolet. Infrared light is noticed simply as the heat felt from the sun or even the warmth of a campfire on an otherwise chilly night. Display or storage under infrared heat can cause deterioration in many of our specimens. 

Secondly, visible light may damage materials as well. While this may come from the sun, light fixtures may also send many harmful lumens of light energy onto a surface. Visible light is all around us--it is how we see and also how our specimens fade over time. We can work to decrease possible damage with energy-efficient bulbs or windows, but visible light remains necessary for exhibits to work. 

However, the most detrimental form of light comes from the ultraviolet (UV) range. It is the wavelength responsible for sunburn and also accounts for nearly 50 percent of fading damage to specimens. Because it is so harmful, and so present in a building with many windows, the Cable Natural History Museum has made some recent changes to better protect its collections against this light. 

Filtering films on classroom windows reject UV
rays with virtually no tint or changes in visibility.

The Museum has a large exhibit hall and classroom space with nearly 40 window panes combined. These windows open up the building to the colorful flower gardens around the property and allow for natural light throughout most of the building. As any visitors to the Museum know, the building itself integrates the environment and architecture. Our green features include energy-efficient windows and light fixtures. Unfortunately, our windows' built-in light filtering has only guarded from some of the incoming UV light. Museums often have to take one step further to stop this, and we did just that over the past week by installing UV filtering film. 

Taken after film installation, this level of UV light
is now more appropriate for specimen display.

When window panes themselves cannot filter out enough ultraviolet radiation, additional window films can. These films have been installed on windows and doorways in the Lois Nestel Memorial Exhibit Hall, our education classroom, and a doorway in an adjacent hall. Regular monitoring of both visible and ultraviolet exposure has shown that UV light levels, measured in microwatts per lumen, have been much too high for museum standards. They exceeded 1,000 µW/l when they should actually be below 50. Once the new UV filtering film had been installed, measurements were again taken and the changes have been astronomical! The most troubled areas are now hovering around 15 µW/l. Considering it is virtually impossible to filter out all UV light, this is a great success. Happy with the results of our preservation project, I can now enjoy some of this brilliant summer sun with much less worry.