Light damage is cumulative and irreversible – and affects more than just the brightness and color of an object. Fading is only one result of light exposure; materials such as paper, fabric, and leather can suffer physical and chemical damage. This is the reason for the low light levels in many exhibits, and also the reason for rules such as “no flash photography.” (Yes, even one flash adds to the problem; remember, the damage is cumulative!) Thus, exhibiting anything becomes a balancing act between preservation and access, and the question becomes even trickier when the exhibited material is particularly old, fragile, and rare. Such is the case with the manuscripts on display in the Study.
The National Library of Israel, to whom Dr. Friedenwald left his collection, very kindly agreed to allow us to display a few chosen works for this multi-month exhibition – but with restrictions, including the length of time any one page could be exposed. Even the dim, low light we use is dangerous to the inks, colors, and paper on display. As scheduled, then, last week we changed all these ancient books to a new page spread, specified ahead of time after discussion between Karen, our curator, and the conservators at NLI. We’ll change them one more time before the exhibit closes in January. This way, no page is exposed for more than a few months.
Each book is supported by a custom acrylic cradle; some require a new cradle when the page spread is changed, since a book will shift on its spine depending on how far into the book you are. Most are also gently restrained with strips of inert, clear plastic film. The goal is to keep the book open to the required page without putting any pressure or stress on the covers, spine, binding, or leaves.
The benefit to you, the visitor, is that a repeat visit will bear fruit! There are fresh pages for you to examine in these centuries-old manuscripts.
To learn more about the science behind light damage, and ways to prevent it while material is on display, check out these links:
- https://www.nedcc.org/free-resources/preservation-leaflets/2.-the-environment/2.4-protection-from-light-damage
- http://www.nga.gov/content/ngaweb/conservation/preventive/preventive-light-exposure.html
- http://www.loc.gov/preservation/care/light.html
- http://www.ccaha.org/uploads/media_items/light-exposure-of-artifacts-on-exhibition.original.pdf
- http://www.philamuseum.org/conservation/10.html?page=2
And for fun, here’s a list of terms for the parts of a book:
http://www.alibris.com/glossary/glossary-books
Post by JMM Collections Manager Joanna Church.
JMM Interns share their perspectives on “turning the pages:”
Turning a new Leaf on an Old Face: Changing the Pages on Medieval Medical Texts