As I was pondering this week’s blog I started to think about some of the tasks we undertake to ensure that the examples of material culture in our collection remain available for future researchers. This is especially true when we realize that the last word in interpretation of objects is never the last word. In the future, researchers, armed with new data and perspectives, will revisit these objects and contribute to a new, perhaps revolutionary, understanding of our experience. So in the end it comes down to what we describe as proper stewardship of the material we hold in trust for you, for me, and for future generations.
Our behind-the-scenes activities take many forms: inventorying, cleaning, and rehousing of artifacts in archival materials are just a few. Above and beyond that, it is clear that the single most effective way to help preserve objects of all kinds is through maintaining a stable environment. This includes controlling temperature and humidity, of course, but also monitoring light levels, as light energy, from incandescent or fluorescent lights or the sun, can slowly degrade organic material.
We were fortunate enough to be able to replace our aging HVAC (Heating-Ventilation-Air Conditioning) system eight years ago with a new system that allows individual control of temperature and humidity in different exhibition galleries and collections storage areas. While the system can be monitored and controlled there is still a need to record conditions within the many zones served by this system. So first thing every Monday morning I make the circuit throughout the building, conducting visual checks of galleries and collections storage spaces, and changing the weekly plotting charts on the hygrothermographs.
What’s a hygrothermograph, you ask? Well, it is a device that records the temperature and relative humidity of the air in a given space. These readings are plotted out on a graph chart; we use a one-week rotation speed, but if desired we could plot one day, or even one month on a chart. The charts afford a quick snapshot of changes in environmental conditions over each week, enabling us to make adjustments to the environmental control settings. Four times a year I recalibrate these units using a thermometer and a sling psychrometer (which measures relative humidity).
In monitoring light levels we use a pair of devices: a good quality light meter and a UV light meter. Since we have already established suitable light levels in collections storage areas, we use these particular meters to check light levels in exhibition galleries. At the opening of each new exhibition I work with exhibitions staff to adjust lighting as needed for protection of the objects. If you are touring through an exhibition and find a particular part of a gallery seems a bit darker, chances are it is due to the need to protect light sensitive materials like paper and fabric.
The tools of the trade are relatively simple (though advanced computer-based recording systems are now available), but they are important players in our responsible stewardship of collections.