What’s that thing on the wall?

Art Windsor-Essex
2 min readMar 10, 2021


By Nicole McCabe, Curatorial Coordinator at The Art Gallery of Windsor

What’s that thing on the wall? Is it a seismograph?
Nope, it’s a hygrothermograph! We use these machines to measure the temperature and relative humidity in the galleries and storage vaults. There are two little pens that draw on the graph paper during the span of one month.

Is that hair in the little cage?
Yes, it lengthens or shortens depending on the humidity in the air, and the connecting lever moves the pen to document the humidity level.

Why does it matter?
Artwork is highly susceptible to extreme temperatures and humidity. Rapid changes in either — or both — of these conditions cause paper and canvas to expand and shrink, which can result in paint cracking. High humidity can support mould growth, which can stain and corrode the artwork. The target, or set-point, temperature for our galleries and storage vaults is 18 degrees Celsius, with an acceptable range of 2 degrees higher or lower. The relative humidity set-point is 50%, with an acceptable fluctuation of 5%. If the temperature or relative humidity rises or decreases outside these acceptable ranges, we call on colleagues with the City of Windsor to look into the issue, and they adjust or repair the HVAC system if needed.

Why do we need to keep track of this information?
We are responsible for taking good care of the AGW’s collection and any artwork we have borrowed from other institutions or lenders. Consequently, we need to be able to show that the conditions where we exhibit and store artwork are under control. When we ask to borrow art from other galleries, we send these graphs to show that we will care for their artwork in the same way we care for the AGW’s collection. The AGW has been designated Category A by the Government of Canada because we can ensure the long-term preservation of cultural property for you and for future generations to enjoy.

Nicole McCabe is the Curatorial Coordinator at the AGW, coordinating all exhibitions, publications, loans, shipping, acquisitions, and collection registration.



Art Windsor-Essex

Art Windsor-Essex (AWE) is a non-profit public art gallery that uses the power of art to open hearts and minds to new ideas. Change happens here.