Constitution 225: Conservation and Re-encasement
In light of the upcoming 225th Constitution Day on September 17, I spoke with Mary Lynn Ritzenthaler and Catherine Nicholson, two of the very few people who have touched the Constitution in the last century, about how they approached the task of conserving the Charters of Freedom.
Before Ritzenthaler and Nicholson took it out for examination and conservation in 2000, the Constitution had been sealed in encasements created by the National Bureau of Standards nearly 50 years earlier. These encasements were made of two pieces of glass with a soldered lead seal around the edges, surrounded by a decorative brass frame. Inside each encasement, the parchment rested on several layers of high-quality handmade paper, with a third piece of glass resting on the parchment like a paperweight to hold it flat. The cases were filled with helium, an inert gas, to prevent damage by oxidization.
These encasements were state of the art for their time, but after 50 years, they left some things to be desired by today’s standards. Parchment isn’t naturally flat, so the loose glass on top of it created “a washboard effect,” according to Nicholson. It also rubbed the surface of parchment, and might have affected the parchment and ink. However, Ritzenthaler stressed that the old cases were very forward-thinking for their time. The inert gas was not commonly used with historic documents at the time, and it did protect the document from oxidization. As Ritzenthaler said, “The NBS encasements did an excellent job of protecting the Charters for many decades; we were able to incorporate a number of design improvements in the new encasements.”
New Case Design
Ritzenthaler and Nicholson were part of a design team that consisted of NARA staff from Conservation, Preservation, Exhibits, and Facilities as well as outside experts. They considered how best to protect the documents using conservative but effective techniques. They wanted to fill the case with inert gas again, as “we felt that was really a good way to preserve the documents,” said Nicholson.
They also chose to fix the Constitution to the platform for stability, but used clear edge tabs rather than adhesive. They installed environment-monitoring systems so that conservators can now detect the oxygen content and the internal temperature and pressure inside the cases.
What They Found
When it came time to open the old encasements, Ritzenthaler and Nicholson made a detailed plan of action. “There was no instruction book for how to open them,” said Nicholson. “The goal was to quickly secure the document so its humidity did not change too rapidly and the papers that had supported it so they could be tested later for moisture content.”
Once the encasement was opened, Ritzenthaler and Nicholson were able to examine the condition of each parchment and look for damage that had occurred in the past. Fortunately, they found that the loose glass sheet had not lifted any flakes of ink from the surface of the parchment.They examined the ink letter by letter and used warm parchment size (a type of adhesive) on a fine-tipped brush to relax lifted flakes back to the surface of the parchment. This treatment secured the text so that it was safe to turn the parchments over. Nicholson and Ritzenthaler were eager to secure the ink text of the document, because “there was another mystery—what would be on the back?” said Ritzenthaler.
“There were no handwritten annotations on the back of the parchments and no treasure maps,” Nicholson laughed, referring to the movie National Treasure. “But there were broad strokes of glue, so we know that the documents must have been glued to rigid supports at some time in the past.”
In the examination, they found identical single puncture holes at the center of the upper edge on each page. Nicholson hypothesizes that the sheets of parchment—which are made from animal skins—were threaded together through these small holes and sold as a set. This would explain how five matching parchment skins were found despite the difficulty of finding such large, uniform parchments. Being sold together as a set explains their consistent appearance.
The conservators also noticed erasure marks where the penman scraped away a word or an entire line of ink with a penknife. They could also see rule lines, which served as a guide for writing long, straight lines of text.
Some lacy nibbling at the top edge of the Constitution pages and a snowflake-shaped hole at the bottom edge of the transmittal page are evidence of insect feeding damage. Nicholson explained that the presence of insect damage gave another good reason for to fill the old encasements with inert gas: It created an anoxic and well-sealed environment that no insects could penetrate or survive.
“The goal of conservation treatment was to make the parchment edges intact and safe to mount,” said Nicholson. To repair the insect damage, Nicholson and Ritzenthaler used parchment size and handmade Japanese paper. They also removed the gummed linen repairs at the tops of the pages. These older repairs held together original vertical slits, which were intended to lace the pages together with ribbon. There was also a small amount of surface grime, which the conservators cleaned from the bare parts of the parchment, careful to avoid text and other original markings.
Ritzenthaler and Nicholson were also careful to document their treatment steps and the condition of the Constitution for posterity. As Nicholson explained, “Conservation methods used on the Constitution in earlier eras were not recorded and are lost for history.”
“It was a wonderful opportunity to be able to examine these documents so closely,” said Ritzenthaler. She explained that compared to the Declaration of Independence, “ the Constitution is in very good condition. The writing is sharp and clear; the parchment is in very good condition. . . . The Constitution wasn’t exhibited as frequently [as the Declaration], and it shows the physical evidence of that.”
A Prologue article written by Ritzenthaler and Nicholson tells you much more about the conservation work done on the Constitution, the Bill of Rights, and the Declaration of Independence. You can see the Constitution at the National Archives Building in Washington, DC, where it is on permanent display.
Posted by Nikita on September 4, 2012, under - Constitution.
Tags: Catherine Nicholson, conservation, Constitution, Constitution 225, encasement, helium, insect damage, japanese paper, Mary Lynn Ritzenthaler, National Bureau of Standards, parchment size, preservation