Further Debunking the Myth of Artifact “Rest”
North Carolina’s Anne Lane initiated a discussion several months ago on an international blog—“Registrar Trek” about light damage and the usefulness of exhibit rotations for preservation. [We also picked up on this idea in one of our posts last spring.] Our whole C2C team is a fan of Anne’s; she is an extraordinary collections manager who is currently working at WCU’s Mountain Heritage Center and previously devoted many years of her professional life to the Charlotte Museum of History. She combines broad preservation knowledge with impressive hand skills and a helpful spirit, and we’ve been fortunate enough to benefit from her as guest poster for this blog, as well as an instructor for C2C box-making workshops. Anne’s Registrar Trek post elicited two useful responses from preservation experts. Both stress the need to assess of a variety of risks more holistically, rather than a singular focus on light damage. Instead of leaving them embedded in the comments section of Anne’s post, it may be helpful to our readers to see them up-front here.
1. Mark H. McCormick-Goodhart, Director, Aardenburg Imaging & Archives: I don’t know of any materials that rejuvenate from light induced damage in dark storage. I do know of materials that continue to degrade due to light-induced damage after removal from display and subsequent dark storage. I also can cite materials that can recover from some discoloration by fresh exposure to light, but it’s kind of a catch-22 as some components (e.g., inks on paper) in the artwork are being further degraded while other components (e.g., color of the media) are being improved by further exposure to light.
The key knowledge to be acquired by curators and conservators is not easy to gain in many instances, but it is how the light fade resistance compares to other degradation pathways. When a material is very light sensitive, it’s pretty much guaranteed that light exposure on display will be a major factor of concern, but with materials of moderate or high light fade resistance, then other weak links like gas fade resistance, thermal and humidity degradation, etc., may prevail in such a way that worrying about amortizing the time in the light on display may be totally irrelevant. Policies for storage and display need to be decided based on better understanding of all the likely variables of decay and not just one variable only since the variable in question may not be anywhere close to being the weak link in the chain.
2. Robert Waller, Ph.D., CAPC, FIIC, President and Senior Risk Analyst for Protect Heritage Corp.: Mark makes an excellent point about needing to evaluate light damage relative to other risks to the collection in order to understand its importance. It would be a shame to keep objects from view only to have them degrade in other ways or be lost to fire, flood, or theft long before their useful display life has been used. Recognizing the importance of considering risks in context is the driving force behind leading institutions now embarking on comprehensive collection risk assessments. If there are one or more risks other than light damage that dominate the risk profile to a collection then there may be little point to rotating which objects are on exhibit.
It is also important to realize that rotating objects from the collection on and off exhibit does not reduce light damage to a collection as a whole but simply alters its distribution. In some cases distributing light damage more broadly through the collection will result in greater loss of value from the collection. The change in object value seldom has a simple, straight line relation to extent of light damage. Usually the change from a “pristine” state to a “just noticeable change” results in a much greater loss in value than a just noticeable change step somewhere in the mid-range between pristine and completely damaged. This is generally recognized by herbaria who, knowing that dried plant specimens are extremely light fugitive, will choose only one page of a bound herbarium to be opened on exhibit. In this way light damage to the contents of the book is restricted to a single page. The remaining pages remain in the near pristine state for occasional viewing. In contrast, if the book has 100 pages and a different page is displayed each month then it would only be a matter of decades, if not just years, until every plant specimen in the book was severely faded.
Agnes Brokerhof and colleagues presented this issue well in their 2008 paper, now available in book form.
Thanks to Anne for getting this conversation going, and thanks to Mark and Rob for such an insightful discussion and their willingness to share it with our audience.
Posted on January 20, 2015, in collections care, Exhibitions, storage and tagged Anne Lane, light damage, Mark H. McCormick-Goodhart, Registrar Trek, Robert Waller. Bookmark the permalink. Leave a comment.