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A Conservative Approach

Saving the National Treasures homepage

It's good to be cautious when you're handling the Declaration of Independence, a document so famous it even had a starring role in a recent Hollywood movie. Mary Lynn Ritzenthaler and Kitty Nicholson of the National Archives' Document Conservation Laboratory had the heady but heavy responsibility of uncasing, examining, and treating not only the Declaration but also the Constitution and Bill of Rights—seven fragile pieces of parchment collectively known as the Charters of Freedom. Here, they reflect on their nail-biting work, reveal what's really on the back of the Declaration, and explain why conservators today, unlike in the past, avoid heavy-handed restoration.—Susan K. Lewis

Opening act

NOVA: You were the first people to set eyes directly on the Declaration, not obscured by glass, since the 1950s. How did it feel?

Nicholson: The actual moment of opening the encasement for the Declaration was truly remarkable—kind of a magic moment. I think neither of us would have dreamed that we would have this honor and challenge when we started working for the National Archives many, many years ago.

NOVA: Would you describe your emotion as more excitement or anxiety?

Nicholson: It was more an excitement that we had reached this point in the project. It's a little like saving the best for last. We had a couple of years on the project at that point. We had started with the encasements and documents that were not on exhibit—the middle pages of the Constitution and Transmittal Page [a letter, signed by George Washington, that accompanied the Constitution when it was sent to Congress]. And at that point there was more uncertainty. Is this going to work? Is this tool going to do what we need it to do?

NOVA: Was it difficult to figure out how to just open the cases?

Ritzenthaler: Well, the encasements did not come with any instructions. We did have good documentation in terms of the elements that had been put together, but we didn't really know, except by using the diagrams, how we would go about breaking the seal and then removing the layers.

Nicholson: If you see pictures of the way we were cutting into this little lead ribbon that joined the front and back pieces of glass, it might look like we were just sticking in a sharp point and that the parchment was just on the other side. But I have to say that we're really grateful to the people who designed that encasement; there's actually a metal collar inside, all around the four edges of the parchment. When we were cutting, our blade would hit that inner metal collar, but it never went beyond that. We knew that structure was there, so it made it much less worrisome.

NOVA: Why did you save the scraps of lead ribbon?

Ritzenthaler: People who work in conservation retain as much physical evidence as we can for future studies. There was a great deal of interest, for example, in knowing how well those encasements had fared during the 50 years that they were in use.

NOVA: Could you tell whether they had leaked?

Nicholson: That was one of the exciting puzzles. People had worried about that even early on. There was a letter in the files in the '50s: "You're going to lose all the helium." But actually all of them still contained helium, which is a really amazing feat of engineering, because helium is a very small atom and can leak through very, very small breaks, passages. It can even leak through certain kinds of glass.

NOVA: What were conditions like in the room where you worked on the documents? Did you have to wear surgical masks?

Ritzenthaler: There were certainly trying times when we had to maintain a "clean room" environment—largely when we were putting the documents into the new encasements, because we did not want to have to open them up again to deal with small specks or spots of dust. But in general the most important feature was the environmental conditions, which were maintained to match the final condition that the documents were going to be exhibited in. So we had a temperature that was around 68 degrees, and a relative humidity of 38, 39 percent.

Nicholson: A very, very close-controlled state. And that was a remarkable accomplishment.

“ old fingerprint of Napoleon on a document—would you want to remove or alter that? You have to think about the origin of the dirt.”

NOVA: After you opened a case, could you flip the parchment over right away and examine it front to back?

Nicholson: Our first concern was to make sure that all of the ink was secure before we turned any of the documents over. And so we carefully examined, letter by letter, to see if there were any insecure flakes of ink. We actually never saw one totally dissociated from where it belonged. What we saw were lifting flakes—a little bit like an old exterior paint on a house. When we found ink like that we would use a kind of parchment gelatin to relax the flake back into its original location.

NOVA: Must take a steady hand.

Ritzenthaler: It does take a very steady hand. It also takes a lot of time. It was many weeks before we had the opportunity to turn the documents over. That was another of these momentous occasions.

Damaged by love

NOVA: When you finally turned the Declaration over, was there a secret map on the back?

Ritzenthaler: We didn't see one. Or any secret messages.

Nicholson: There was an inscription written along the bottom edge so that if it was stored rolled, as was the norm in the 19th century, you could say, "Aha, here's the Declaration."

NOVA: What did it say?

Ritzenthaler: A direct quote: "Original Declaration of Independence. Dated 4th July 1776."

NOVA: Over the centuries, what did the most damage to the Declaration?

Ritzenthaler: Well, the Declaration clearly was one of the most loved documents in American history. It was handled a lot. It was displayed and exhibited. It was removed quickly from Washington during war periods. We wouldn't say that it was mishandled, but it was handled in ways that are different than approaches we would take today. We wouldn't roll the document, for example. We know that it was rolled. It was displayed under conditions of relatively prolonged exposure to light. We wouldn't do that either.

Nicholson: It was the document that Americans first saw as the pivotal founding document. So from the early 19th century, people, when they visited Washington, if they had any pull, they'd expect to go to the State Department and have it brought out for them.

NOVA: Are there any surprising marks on the document?

Nicholson: Well, the handprint is the one that people get fascinated by. It's at the bottom left of the front of the document. We really don't know the history of the handprint. So it's even mysterious. [See The Damage Done to examine the handprint and other details on the Declaration.]

NOVA: Did you think about attempting to remove the handprint?

Ritzenthaler: We had discussions with the archival staff. We weren't certain that it would be feasible, but we wanted to talk through whether or not, from an archival perspective, it would be appropriate or ethical. For a whole lot of reasons we decided to leave it. We felt that it really is now part of the document.

NOVA: Is the dirt on the documents even part of their history—something to retain?

Ritzenthaler: From a conservation perspective dirt can be abrasive. It can be acidic. On the other hand, an old fingerprint of Napoleon on a document—would you want to remove or alter that? You have to think about the origin of the dirt.

“Restoration implies that somehow you can wave a wand and turn back the clock ... we know that's impossible.”

NOVA: Why were you so meticulous in examining the documents—noting every single crease and speck of dirt?

Ritzenthaler: There is so much about the history and the condition of these documents that really has not been reported. So for future conservators and custodians we wanted to record as much information as possible, something to compare against in 50 or 100 years.

NOVA: The Charters are on display to the public every day of the year except Christmas. Has the Archives considered limiting that time to help preserve them?

Nicholson: The Archives feels that it's really politically necessary and philosophically necessary that Americans can always see these founding documents. They're sealed in inert gas to protect them from photo oxidation, which is a fancy chemical way of describing light fading. So we have reason to believe that the absence of oxygen will actually make them remain in very good condition.

Ritzenthaler: Incredible steps have been taken, more so than with any other documents that I'm aware of in the world, to make sure that we have provided a stable preservation environment. Temperature, relative humidity, controlling the light exposure. [To learn more about how the ink and parchment deteriorated in the past, see Fading Away.]

Turning back time

NOVA: At some point in the past, someone touched up the ink on some of the Declaration's signatures, including the famous John Hancock. Why wouldn't you consider doing this sort of restoration work now?

Ritzenthaler: That hits on one of the most important premises for conservators who work with archival documents. These documents are historical evidence. We would never do what we would consider cosmetic improvement. Our aim was to enhance visibility and the long-term preservation, but not to cosmetically alter the document.

NOVA: You did do some repair work on the edge of the parchment. How do you draw the line between restoration work that's okay and tampering that distorts the document's history?

Nicholson: That's a good question. Altering the text, altering signatures, altering anything that conveys meaning—down to commas and periods—would be totally inappropriate. The work we did was on a gap on the right edge where there was no writing. It was an area that was somewhat jagged, and it had potential for catching on the clear plastic tabs that fold over the edge of the document and keep it in place in the new encasement. We did try to make the color harmonious with the adjacent parchment. But if you look at it closely, it would never be deceptive.

Ritzenthaler: Our goal clearly was not to fool the eye or to make the document look pristine.

NOVA: Do you think restorers of the past went too far?

Ritzenthaler: There was a period in the middle decades of the last century when there were exquisite approaches to replicating areas of lost text. That's not something that we would think appropriate in an archival context.

Nicholson: There are some Old Master prints that were restored in a way that's really too much—they went to great lengths! It was not visible from the front or the back what had been done. That, I think, goes in the direction of deceptive restoration. There's one document I know of where half the document was discovered, and the other half was missing. But it existed in multiple copies, and a very, very good facsimile was made of the missing portion, and it was joined together. Probably when half the document is gone you should just say, "We only have half the document."

NOVA: Has there been a shift in recent decades in the philosophy of those who work on historic documents and artifacts?

Ritzenthaler: There has been a shift. Kitty used the phrase earlier, "Do no harm." I think that people in general tend to intervene less than they used to.

Nicholson: "Restoration" versus "preservation"—I think that kind of sums it up. Restoration implies that somehow you can wave a wand and turn back the clock, and it's the way it was when it was new. And we know that's impossible. Ultimately, you can maybe do something that's cosmetic, that suggests the way it ought to have looked, but you just can't turn the clock back. Preservation is more future-oriented—taking the steps today that will make something last as long as possible. And what we were doing with the Charters, with the Declaration in particular, was to do all the things we need to preserve it for future generations.

Safe haven

NOVA: In the early 1950s, when the Charters were put into their then state-of-the-art cases, how long did the conservators and case designers expect they would stay there?

Nicholson: I think they thought they would last quite a long time. But no one ever really made an estimate. I think they just didn't know.

Ritzenthaler: They created encasements that were not capable of being opened and then re-used. So maybe that spoke a little bit to their sense of permanence.

Nicholson: Or lack of forethought.

Ritzenthaler: Yes, lack of forethought. And certainly one of the major design ideas that we had in thinking about the [new] encasements was that they could be opened and then re-sealed. [To examine the new encasements, go to Case Closed.]

Nicholson: We anticipate at some point they'll need to be opened. But we don't think it will be in our lifetime.

NOVA: Is it unsettling to you that the cases made in the '50s needed to be opened 50 years later?

Ritzenthaler: No, I think that the technology actually was superb and lasted a very long time. It was very effective in protecting and preserving the documents. I think if they had not been encased at that point, they would have been in great jeopardy.

Nicholson: It was 50 years of a safe environment that they had not had for many, many decades prior to that.

NOVA: Is it possible, given the sophistication of the new cases, that the documents could suffer absolutely no deterioration from here on out?

Ritzenthaler: I don't think that we're actually in a position to make a definitive statement like that. I do think that the Archives has taken every precaution that we can tap into in terms of the current understanding, materials, methodology.

NOVA: You spent about five years on the Charters project. That's a long time.

Nicholson: It was a good long stretch. But this was an engineering project, a construction project. It was quite a complex project, and the conservation was just one part of it.

Ritzenthaler: And it was an amazing collaboration. Not just the conservators were involved, but engineers and chemists and physicists, and people who had expertise in metal and gold plating and glass. So it was really quite a fabulous gathering of expertise.

NOVA: The Declaration and the other Charters are seen by many people as almost spiritual, sacred objects. Having worked on them for so many years, do you see them that way or as material objects made of parchment and ink?

Nicholson: Well, conservators always see things as material objects. That's the kind of people we are! But we also see them as incredibly significant documents.

Ritzenthaler: They're certainly awe-inspiring. I think we both feel that it was an amazing privilege to work on them.

NOVA: What's it like when you go to the Rotunda and you see school kids and other visitors looking at the Charters? Do you feel a personal sense of gratification?

Ritzenthaler: I certainly do. I think we both also feel pretty protective. A sense of maternal oversight.

Nicholson: One of the really nice things about the project for the Charters was it included making the display more accessible. And I get a really big satisfaction from seeing small children and people in wheelchairs able to come right up and see these documents. It really is very satisfying.

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Glass removal

Conservators Mary Lynn Ritzenthaler (left) and Kitty Nicholson (right) carefully remove the top layer of glass from one of the 1952 encasements housing the Charters of Freedom.

Open seal wide

NOVA's camera captures Kitty Nicholson cutting through the lead strip sealing the encasement of the Declaration, while Mary Lynn Ritzenthaler holds the case steady.

Lead seal removal

A steel cutting tool specially designed and made for the task works almost like a can opener.

Document removal

In its 1952 case, this page of the Constitution rested on 12 sheets of paper custom-made by the National Bureau of Standards (now the National Institute of Standards and Technology). After the case was opened, the paper was quickly secured in an airtight container for later moisture testing.

Restoration steady hand

Why did the conservators sometimes use bare hands as they examined and treated the Charters? Find out.


When they repaired a corner of the Declaration where parchment had broken off, the conservators used toned Japanese paper that would have a harmonious but not deceptive appearance.

Doris and daughter

Doris Hamburg brought her daughter to the newly designed Rotunda for an intimate look at the documents that define a nation.

Wheelchair at exhibit

Where before visitors climbed steps to view the Constitution on a raised platform, they now can walk or roll wheelchairs to the encasements at ground level.

Saving the National Treasures
Fading Away

Fading Away
We've all seen materials damaged by light. But what's actually happening?

A Conservative Approach

A Conservative Approach
Conservators on the light touch they used to treat the Charters of Freedom.

The Damage Done

The Damage Done
On this high-resolution image, closely examine the time-worn Declaration.

Case Closed

Case Closed
Explore the special Charter encasement in this interactive 3-D animation.

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NOVA Home Find out what's coming up on air Listing of previous NOVA Web sites NOVA's history Subscribe to the NOVA bulletin Lesson plans and more for teachers NOVA RSS feeds Tell us what you think Program transcripts Buy NOVA videos or DVDs Watch NOVA programs online Answers to frequently asked questions