CCI Newsletter, No. 33, May 2004

Preservation Study of the Declaration of Independence, Constitution and Bill of Rights

by Gregory Young, Senior Conservation Scientist, Conservation Processes and Materials Research

The British parliament passed the Stamp Act in March 1765. Intended to help pay for the global Seven Years War that Great Britain had just won and to help keep an army in the Americas, this new tax on paper and documents precipitated growing sentiment against British rule and foreran another decade of political and economic conflict. The open hostilities that eventually broke out in Lexington and Concord, Massachusetts, set the American Revolution in motion. On July 4, 1776, a year after the war began and weeks before 30,000 British troops sailed into New York harbour, a majority of the 13 colonies adopted the Declaration of Independence; by July 19 it was unanimous. In September 1787, four years after the signing of the Treaty of Paris that officially ended the war, the Constitution of the new United States was adopted. At the First Congress of the new republic in 1789, the Bill of Rights comprising the first 10 amendments to the Constitution was drafted to allay long-standing concerns about potential future violations to individual freedoms.¹

These three parchment documents comprise the Charters of Freedom of the United States of America. For 50 years, ending in 2001, the individual pages of the Charters were sealed in hermetic glass cases in a humidified helium atmosphere. For most of those years, the three, including just pages one and four of the Constitution, were on display in the Rotunda of the National Archives Building in Washington, DC.

On July 5, 2001, the Charters were removed from the Rotunda during major renovations. Microscopic crystals and liquid droplets had been detected by microscopy in 1987 on the inside surface of the original glass cases. During the following eight years, the cases and parchments were monitored for any change using the Charters Monitoring System developed by the Image Processing Lab of the Jet Propulsion Laboratory. The conclusion reached was that the crystals and droplets were the result of glass deterioration. Therefore, during the renovations, the parchments were removed from their degraded cases, examined and placed into newly designed encasements that employ a humidified (45% RH) argon atmosphere held at 19°C. Rededication of the Charters in the renovated Rotunda took place on Constitution Day, September 17, 2003. The seven new cases were built by the National Institute of Science and Technology; six for the Charters and one for the Transmittal page of the Constitution. Unlike the old cases, the new ones can be re-opened to examine the parchments if and when necessary.

CCI participated in examining the Charters' parchment. Conservators at the National Archives and Records Administration (NARA) requested that thermal stability (shrinkage temperature) measurements be taken from microscopic samples to determine the current state of the parchments' preservation. The work included studying any detectable difference in stability between the pages that had been on display during the past 50 years and those that had not. As well, the effect of the iron gall ink used to handwrite the documents was studied.

Sample quantities were, of course, severely limited. This presented real challenges both for the measurement technique and for sample preparation. In response, CCI began redeveloping much of the technology. The short article "Quantitative Image Analysis in Microscopical Thermal Stability Measurements" in CCI Newsletter No. 31 (June 2003) described just one of the current three methods that use combinations of computer algorithms to obtain numerical data from microscopical images of the parchment samples.

Just as egg whites change during cooking from clear and fluid to white and solid because of heat-induced protein denaturation, the collagen fibres in the parchment samples shrink up to 70% in length because of denaturation. Each of the three methods teased out data on this shrinkage phenomenon from 220 time-lapse digital images taken of the fibres in each sample. The images were collected as the samples denatured and shrank during heating in the microscope. What is significant in the data is that the temperature range within which the shrinkage occurs depends on the degree of chemical and physical deterioration in the fibres. Lower temperature ranges indicate greater levels of deterioration.

At this writing, the project has produced over 100 gigabytes of image data, which are currently being used to determine the starting temperature of fibre shrinkage by the three methods. Early on, during examinations at NARA, initial results helped set limits to handling and to designing potential treatments. When completed, the project will also establish benchmark values for the parchments to which any new measurements can be compared in future studies monitoring change over time.

Meeting the demands in the Charters project for improved precision and accuracy in the measurement technique has allowed CCI to renew this avenue of broad practical research on collagenous materials. Above all, the project gave CCI the extraordinary opportunity and privilege to make a contribution to the preservation of some of history's most significant documents espousing democracy.

1. The Declaration of Independence and Bill of Rights owe much to the deliberations of George Mason, the author of the Virginia Declaration of Rights (1776). The ideas expressed concerning inalienable individual rights arose during the Age of Reason and contributed to popular revolutions on two continents in the late 1700s.