By Kristi Wright and Holly Herro ~
The Leather Discussion Group, an ongoing cross-institutional research collaboration, is conducting research to determine the best products available to suit book conservation needs and to communicate our requirements to leather manufacturers.
In 2017, we sent a survey to a group of conservators and tanners to gather data on leather practices. We also embarked on an exploration of previous leather studies in both Europe and the United States that yielded information dating back to the first formal leather research in the 1840s. Ongoing conversations with leather chemists, tanners, and conservators in other disciplines continue to provide valuable feedback.
Most recently, the group has started to consider the potential impact of animal husbandry on skin quality. For example, changes in animal husbandry driven by increased worldwide meat consumption may also affect the properties of the leather, a byproduct of that industry. The group was thrilled to be able to consult Colonial Williamsburg Foundation Curator of Zooarchaelology Emeritus Joanne Bowen and Rare Breeds Manager Elaine Shirley due to their expertise on this topic.
This year we presented posters at the 2019 AIC Annual Meeting in Uncasville, Connecticut and the International Council of Museums Committee for Conservation (ICOM-CC) Leather Working Group interim meeting in Paris, France.
The research explores the evolution of North American animal husbandry from the 17th century to the present, focusing on changes in breed choices, diet regimens, environmental conditions, and abattoir trends that could have an impact on leather quality.
Beginning in the 1800s, a shift from multi-purpose, hardy, and adaptable animals to highly specialized breeds that excelled at a particular purpose—such as dairy, meat, or wool production—was accompanied by changes in diets and environmental conditions. Early, multi-purpose, animals foraged freely in the woods, and fences were intended to keep them out of farmers’ fields rather than in a pasture. These changes took place as human populations increased and many farmers’ goals transitioned to optimizing animal products for sale. The resulting practice of penning livestock, first in fenced pastures and later in confined stalls, changed animals’ diets in notable ways. A reduction in nutrient uptake from traditional forage led to the need for supplemental feed in the form of corn, other grains, and the leafy tops of root crops. Specialized breeds require increasingly specialized diets and many now cannot survive on forage alone.
Multi-purpose livestock were often used around the farm, so farmers typically waited until animals were older before ultimately slaughtering them for meat. Modern animals, which are typically raised for a specific purpose, are often younger when they are slaughtered. Early butchers were close to farmers and tanners but now hides are sometimes shipped long distances, which can affect their preservation.
How do these changes impact the skin’s composition? Do any of them ultimately affect the leather quality? The group is currently undertaking research into these topics with a comparative analysis of both historic bookbinding leather and leather from traditional and modern breeds with known diets.
Acquiring a better understanding of factors affecting leather quality will will improve our knowledge about and ability to care for and preserve leather bound materials at the National Library of Medicine.
Read publications on conservation topics by Holly Herro and Kristi Wright in the National Library of Medicine’s free full-text archive of biomedical and life sciences journal literature PubMed Central.
Holly Herro is Senior Conservator for the History of Medicine Division at the National Library of Medicine.
Kristi Wright is a contract conservator for the Conservation Program of the History of Medicine Division at the National Library of Medicine and principal of Wright Conservation and Framing.