Summer's Coming…So This Must Be Spring
All of us who share an interest in keeping works of art in the safest possible conditions must be especially careful in the spring and fall. In these swing seasons, climate conditions may change dramatically and very quickly.
We welcome the sun after the relative darkness of winter, but the increasing hours of sunlight and brightness of the overhead summer sun mean that artworks (and all organic materials) will be under much more risk of damage from light. Sunlight contains more UV radiation than other light sources, and we always recommend glazing frames with UV blocking glass or acrylic. But that is not enough: even with UV rays removed, sunlight is so much brighter than other sources that it can cause serious deterioration to organic materials. By deterioration, we mean fading of colors, darkening of some non-archival papers, embrittlement of materials, and more.
It seems like common sense that we shouldn’t allow direct sunlight to fall on the surface of an unprotected painting, but maybe it’s less obvious that the same precaution should be taken with works that are framed under glass or acrylic. In fact, studies have shown that direct sunlight falling on a glazed work on paper poses a very severe risk: temporary localized heating can result in the drying and shrinkage of materials, which is very stressful to the object and ultimately damaging.
The relative humidity (RH) in our space may remain stable for days—then a spring rainstorm comes along and causes the RH to spike up dramatically. And, since the temperature is mild, there’s neither central heating nor air conditioning to lower the humidity.
One of the short-term impacts of high humidity is the expansion of paper and matboard, which will become distorted and wavy (as seen below), and perhaps cause a framed work on paper to be pressed against the acrylic or glass covering the artwork. For media to be pressed against the glazing can cause permanent damage.
At times like this it’s good to have de-humidifiers on hand. The goal of de-humidifying is to keep the RH in a safe range and as steady as possible. Gauging which size de-humidifier ti purchase is not too difficult -- one must take into account how humid the space is and how many air changes to expect in a given period. This link give some clear and basic instructions for selecting the right size de-humidifier. http://www.wikihow.com/Choose-the-Size-of-a-Dehumidifier
Of course, a device to measure the RH is also needed—these instruments go by a few different names but the most common is “hygrometer.” You can buy a simple one from TALAS or University Products. They have a few models in their catalogs that measure temperature as well as humidity. As a humidity indicator they are not very precise—plus or minus 5% RH—but they cost only about $50. A more accurate (though also more expensive) option is a data logger, available in these catalogs as well (see image below). These connect to your computer for continuous logging of your temperature and humidity.
Data Logger, image from talasonline.com
Over the course of the summer it is not safe to leave works of art, especially works on paper, in an un-air-conditioned apartment for long. Damage can occur in just a few days. One way to keep electric bills down (and reduce the carbon footprint) when one goes on a trip would be to store all vulnerable works in one room and air-condition and de-humidify (if necessary) only that room.
Vacation homes may be subject to certain risks to artworks. In mountain homes at high altitudes, sunlight--especially the UV component--becomes an even greater issue than at sea level. And the seashore environment too is a threatening one for works of art; the sunlight is intense and the air is salty as well as humid; a potent mix that threatens artworks with rapid deterioration. De-humidification and limiting exposure to sunlight are even more important in such conditions.
Beach house. Image courtesy of community.mis.temple.edu
In general, if you’re going to be away from home this summer, it’s a good idea to cover vulnerable works of art that will be exposed to daylight with a cloth cover that’s light-proof. We’ve been working on a design that can be fitted to the size of the artwork, though we haven’t put it on the market yet. Please let us know if you would like to hear more about it.
And, let us know if you would like more information on any of the issues raised here. We also have an "Environment" section under the Preserving Art tab on our website, here. Finally, if you would like to read more extensively on this topic, see our Recommended Books and Links section (particularly Bachmann and Ellis).
-Jed Bark, Bark Frameworks
Bark Frameworks Newsletter, Vol. 2, June 2014