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How hair helps conserve art

Today's blogger is Laura Mosteller, Conservation Technician II at the IMA.

As the conservation technician at the IMA, one of my responsibilities is keeping an eye on the devices that measure temperature and humidity in the galleries. Why? A major aspect of our mission at the museum and the field of conservation is to preserve artworks for generations, and often these artworks are composed of vulnerable materials. Changes in temperature and humidity can result in stresses of warping, dislocating joins, cracking and lifting of surface layers, breaking fibers, metals corrosion, and cockling of works on paper. Not to mention that mold will thrive at relative humidity levels of 70 percent or higher.

hygro_closedThere are many devices available that enable a real time recording of the gallery environment and we use a variety of these for recording comprehensive data history. What you may be surprised to learn is that one of the devices uses horse or human hair as a very important element for sensing humidity fluctuations. Called a hygrothermograph, it is one of the most common devices used to measure and record temperature and humidity. You’ve likely seen the contraption in many museums and wondered if it was a contemporary work of art.

hygro_openHumidity measuring devices have been around for hundreds of years; in the early days a material that was hygroscopic, or capable of absorbing moisture, was connected to the instrument to act as a humidity sensor.  The substance may have been twine or paper, and it would expand and contract when influenced by the varying levels of the moisture content in the air. These changes in the material could be quantitatively measured to interpret the relative humidity. In the late 1770s, Horace Benedict de Saussure is credited for implementing the sensible hygroscopic material of human hair in his design of the device. It is said that he used the locks of his lovely wife; perhaps the idea came to him after she complained of a bad hair day on a rainy afternoon. In today’s version, hair can be stripped of its oils and gathered in a small bundle providing the perfect humidity detector. So if you’re the type of person who enjoys unusual facts, this one is certain to impress your friends.

Filed under: Art, Conservation, Guest Bloggers, History, Technology

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