Elizabeth Nunan, Judith Levinson, Lisa Elkin, Corina Rogge, Julia Sybalsky, and Becca Pollak
Abstract
From 2010-11, the American Museum of Natural History completed an ambitious program of renovation to the habitat dioramas in the Hall of North American Mammals. Created in the 1940s, these historic dioramas were conceived as a means to inspire wonder and appreciation for the natural world, and to educate visitors about the fragile ecosystems threatened by unregulated hunting and development. Having been on permanent display for over 70 years, many of the zoological specimens were faded to such an extent that they no longer reflected the natural appearance of living animals, compromising the overall impact and effect of the dioramas.
The renovation arose from a re-lamping project in which the original diorama lighting systems were to be replaced with modern fixtures. Previous testing in the Akeley Hall of African Mammals had demonstrated that it was possible to reduce heat and light levels inside the dioramas – while maintaining the desired visual appearance – through the use of energy-efficient lamps. As the re-lamping project would extend the exhibit life of the materials within the dioramas, the renovation team became motivated to explore complimentary methods of restoring naturalistic color to specimens that had become faded and desiccated in the original harsh lighting environment.
Several important factors limited the materials that could be considered for recoloring. As the lighting design in each diorama reflects a specific location, season, and time of day, the light levels often greatly exceed that of a typical art exhibition space. Additionally, the larger taxidermy mounts are permanently embedded into the wire-and-plaster matrix of the diorama floors and cannot be removed for treatment. Finally, the dioramas themselves are not air-tight and accumulate dust over time. For the treatment to be successful, any materials used had to be lightfast, allow for application in situ with no rinsing of excess colorant, and had to impart minimal alteration to the physical characteristics of the hairs, helping to insure that specimens can be cleaned and groomed in the future.
Preliminary investigation into contemporary taxidermy restoration practices revealed few references to materials used in recoloring faded mounts. Some institutions have reported success with commercial hair dyes, while acrylic paints are commonly used among taxidermists. The American Museum of Natural History conservation team ultimately chose to focus its investigation on Wildlife Colors acrylic paint (commercially available acrylic paints used by taxidermists), Orasol dyes (solvent-soluble metal-complex dyes with uses in conservation treatments), and XSL micronized pigments (water-dispersible pigments).
Conservators worked closely with the project taxidermist and partnered with outside conservation scientists to assess these materials against the necessary criteria. Physical attributes of colored hair samples were examined using scanning electron microscopy, and the lightfastness of dyes and pigments was tested using microfadeometry and accelerated aging. The investigation has contributed to a better understanding of aging properties in these materials, and has led to innovative recoloring methods that prioritize long-term stability and retreatability.