Though the Declaration of Independence has always been a beloved symbol of American democracy, the document itself wasn't always preserved under the best possible conditions. Today the National Archives and the National Institute of Standards and Technology are researching ways to preserve the Declaration so that it can be viewed by future generations.

At the National Archives in Washington, D.C., 5,000 to 6,000 tourists wait in line each day to see the Declaration of Independence.

The Declaration was often rolled up and moved from place to place during the American Revolution, and later, when the nation's capital moved from New York to Philadelphia to Washington. It got wet while a copy of it was made in 1823, causing the ink to fade further than it already had.

During the nineteenth century the Declaration of Independence hung for almost forty years near a window with strong northern light at the U.S. Patent office.

Preservation experts suggested in 1903 that it be kept out of light and kept dry. They did not understand then that parchment needs a little moisture to prevent it from cracking.

In 1951 the first modern preservation efforts began. The Declaration of Independence was sealed in a bronze, bullet-proof glass encasement at the National Archives. The damaging oxygen was replaced with humidified helium, which blocks oxygen and other irritants. A filter was added to screen out harmful light. Each night, it is lowered twenty-two feet into a vault.

To see if the preservation efforts were actually working, the National Archives installed a monitoring room in 1987. It is a $3 million computerized camera system designed using technology from the Hubble Space Telescope. The sensitive camera can detect fading or flaking of the ink. It can tell if the document has expanded or changed sizes. And it can even monitor the condition of the glass that sits on top of the Declaration.

The encasement from the 1950s is starting to show its age. Eventually, with continued glass deterioration, the glass will become opaque and the document will become obscured. Contact between the parchment and the glass may cause abrasions to the parchment as well. To prevent this from happening, the National Archives is designing and fabricating new encasements for the Declaration of Independence and the other "Charters of Freedom": The Bill of Rights and the Constitution.

In March 1999 the new encasement designs were revealed. They will eventually be constructed from commercially pure titanium, filled with inert argon gas.

Before the Declaration is re-encased, it will be examined and its current condition will be documented. Baseline photos will be taken. It will be the first opportunity to examine the document outside the glass enclosure in fifty years. If warranted, the document will receive conservation treatment.

The re-encasement will be integrated into a redesign of the entire Rotunda of the National Archives Building to improve public access for viewing the Declaration of Independence. The project is expected to be completed in 2003.