Climate Control: Preserving the HHS Permanent Collection

By Executive & Curatorial Assistant, Caitlin Cummings

For over two years now, the Object of the Week blog has allowed us to bring you a closer look at some of the most special pieces within our permanent collection. This week, we take the time to explain a behind the scenes aspect of collections care: climate control and preservation efforts within our historic structures! A key responsibility of any curatorial department is keeping museum artifacts safe, and with a collection as large as ours (with over 10,000 diverse objects), that can sometimes be a challenge. What many may not know is that different types of materials react differently to environmental variables, and as a result it is crucial that they are housed and handled appropriately in order to remain in excellent physical condition. Especially during these summer months, we are constantly battling heat, humidity, sunlight, and pest issues that could easily threaten the condition of historic artifacts.  Low levels of humidity can, for example, cause desiccation and embrittlement of paper, leather, and textiles, as well as the splitting/cracking of wood. High levels of humidity on the other hand can promote the corrosion of metals, and increase the chances of mold and insect activity.

Our main collection storage area on Huguenot Street is located in a 20th century building, and as a result we have little to no problems maintaining proper climate conditions in that space (with a temperature safe range of 61-68°, and a relative humidity range of 35-55%). Unfortunately stone houses, such as those that line Huguenot Street, are not equipped with insulation, HVAC systems, or any of the other structural amenities we are now reliant on to keep us comfortable at home. This means that the Huguenot houses are particularly dry and freezing in the winters, and alternatively moist and hot in the summers.  Because many pieces within the HHS permanent collection are kept on display in the stone houses to accommodate our recently re-vamped tours, we must ensure that the temperature and humidity within those environments are kept as stable as possible. If we failed to do so, our visitors would have less to enjoy as priceless pieces within the collection could begin to fall apart.

Traditional museum spaces and art galleries have long-been accustomed to measuring environmental conditions with tools called hygrothermographs. These devices are comprised of human or synthetic hair (for measuring humidity) and a bi-metallic strip (for measuring temperature), typically resembling small boxes that sit on the floor. Each sensor is attached to a separate pen which in turn moves up or down in response to a change in humidity or temperature. Because of the sensitive nature of the mechanism, the hygrothermograph requires frequent calibration and is simply not a suitable way for us to measure environmental conditions in all eight of our historic buildings. Historic Huguenot Street, like many other house museums, has instead turned to a new type of technology that provides the same exact data as hygrothermographs; digital climate data loggers. For the past decade, HHS has been evolving alongside these digital trackers, and we are pleasantly surprised to find that the technology is continually improving. Produced by a company called Onset, our curatorial department utilizes a brand of data-reading devices aptly called “HOBO loggers.” These loggers are initially hooked up to a software system that allows us to program their settings; here, you can change the intervals at which temperature and humidity readings are being taken and also specify a loggers “home location”. After the loggers have been digitally set-up, they are taken out and placed into each of the eight buildings. Once they are placed in the correct room (based on their “home location” as it was programmed in the computer), the loggers are turned on and they immediately begin to record the climate changes within those spaces. The best part of these new-age digital loggers is that you only need to collect the data once a month, as opposed to once a day (as was necessary with the hygrothermographs). Thus, once a month we visit each of the loggers and simply connect it to a data reader via a USB cord. Then we simply bring the data reader back to a computer, upload all the recorded information from all of the historic houses, and voila! The climate condition data analysis can begin!

A traditional hygrothermograph (left) and the digital HOBO logger (right) used on Historic Huguenot Street.

Now I know that at this point many are wondering, “so what,” and “who CARES about climate data anyway!?” I guess all I can say is that I used to agree with you; this entire process once seemed tedious and unimportant to me as well. That is until I began to see the devastating effects of environmental variables with my own eyes! This past winter it came to our attention that three of our most prized portraits were succumbing to the significant fluctuations in temperature and humidity that they had been subject to since they were painted in the early 19th century. These fluctuations resulted in the chipping of paint, the buckling of canvas, and in some areas, paint discoloration. We were forced to take action quickly in order to preserve these paintings, and thus had to hire the services of a trained conservator who specializes in painting restoration. Another example is the current situation we face with the Jean Hasbrouck House. Erected in the early 18th century, the Jean House has been a longstanding “face” of Huguenot Street and remains one of the most popular stops on our daily tours. Visitors regularly enjoy the newly re-furnished Storeroom, our impressive collection of Dutch kasten, and of course, the large wooden loom that sits in the Garret. What visitors don’t realize is that all of those beautiful collections pieces are in grave danger due to the deteriorating roof that covers the Jean Hasbrouck House. Although we have managed to catch this problem in the nick of time, structural issues such as a leaky roof or a cracked window are always more devastating when there are museum pieces involved.

While digital climate control is an ever-changing field for historic house museums such as HHS, we enjoy protecting our collection and welcome the publics’ help in that regard. As always, please refrain from touching or handling museum objects while on our guided tours and continue to support our mission by donating online.