However, by 1940 the Bureau determined that these “precious and irreplaceable documents” should not only be preserved but also remain on permanent display to the American People.2 By 1952 most of these items had been sealed within new enclosures and were displayed in the Rotunda of the National Archives. A few years ago, conservators at the National Archives and Records Administration (NARA) noticed irregularities in the glass covering the documents. This prompted them to consider removing the materials from their old housings and fabricating new enclosures that would reflect current advancements in preservation and scientific technology.  The 1952 cases consisted of three panes of glass—one of which rested directly on the documents—that were sealed with lead strips and finished with a bronze frame. The documents rested on a bed of pure cellulose paper, produced in an experimental paper mill at the National Bureau of Standards (now known as the National Institute of Standards and Technology, or NIST). The internal atmosphere of these cases was replaced with inert helium gas and fitted with leak detectors to monitor the enclosures.  Various changes are being incorporated into the design of the new cases. The new 3/8” tempered glass no longer touches the documents. The permanent lead seal has been replaced by a reversible seal ring that will allow the cases to be opened and resealed if necessary. The bed of cellulose has been replaced with at least one sheet of cotton paper that will provide a barrier between the document and a perforated aluminum platform. The helium gas has been replaced with inert argon gas because argon has larger molecules that are less likely to escape. This internal atmosphere will be monitored with both internal sensors and external systems, which will detect any changes in the environment. In the fall of 1999 Don Etherington, a conservation consultant for the re-encasement project, contacted the Research and Production Paper Facility of the University of Iowa Center for the Book (UICB). The NARA conservators were seeking to replace the original cotton support paper which was under the documents and wanted to know if our facility could produce backing paper appropriate for the new encasements. The conservators believed the paper could play an important role in stabilizing the relative humidity within the cases, as well as providing an opaque, sympathetic barrier between each document and the perforated aluminum platform it would rest on. After carefully reviewing NARA’s specifications, Tim Barrett, Director of the UICB and founding Director of the Paper Facility, and I, the Facility’s Paper Specialist and current Director, agreed that we would be able to produce a naturally white paper with a high degree of purity appropriate for the project. Research and Development The first few months of the year long project was devoted to designing the paper and determining our material and equipment needs. I then focused on producing prototype sheets, while Tim oversaw fabrication of a pneumatic press (see sidebar). During the last four months of the project I was responsible for the production of the final paper for NARA. The National Bureau of Standards paper that was used in the 1952 cases was made from 60 percent new white shirt cuttings and 40 percent “old whites,” (probably high quality old white rags) with small percentages of "calcium" (probably calcium carbonate) added as an alkaline reserve and titanium dioxide as an optical brightener.3 NARA’s new specifications required a pure cellulose paper without any additives. Our approach at the UICB Paper Facility in designing and producing paper for the Charters of Freedom was based on a historical model. Early European papers—which relied on extensive washing with pure water and predated the use of harsh chemical cooking and bleaching—have remained stable for hundreds of years. For this reason, we decided to use a high grade, unbleached, textile-quality cotton, provided by Cotton Incorporated of Raleigh, North Carolina. This raw cotton sliver contains minimal non-cellulosic material, which allowed us to produce a very stable paper simply by washing the fiber extensively with hard, filtered water.  Because the project would require us to produce 36” x 36” paper—larger than our current equipment would accommodate—we consulted with other specialists in the hand papermaking field. Jana Pullman of Western Slope produced the three foot square deckle box that the paper would be formed on. Howard Clark of Twinrocker Handmade Paper provided the engineering for the 80-ton pneumatic press designed by Tim Barrett and assembled by Tim and graduate research assistants. Lee S. McDonald supplied the materials and expertise for a forced-air, restraint drying system. Production We began paper production for the Charters of Freedom project in the summer of 1999. Because the UICB is part of a research university, all of our production and research involves training dedicated students. Primarily, three graduate students were involved during the project: Paul Denhoed, Sara Langworthy, and Rebbecca Tomas. For the first step we used a Pekrun FL80 floc cutter, with a guillotine-type blade, to pre-cut the cotton sliver to 2.5 mm. We had already determined that this length was short enough to minimize knotting during the beating stage, yet long enough to provide sufficient strength in the finished paper. We used a filtering exhaust system and particulate dust masks to keep from inhaling airborne fibers during this step. Each batch of 4600 g of pre-cut cotton was soaked over night in 100 l of filtered water. (The Paper Facility uses hard water with a relatively high calcium content, which we pass through activated carbon, iron, and 5-micron particulate filters.) Cotton tends to float because of residual waxes and oils; therefore, we needed a surfactant so that the fiber would take on water. Cotton Inc. recommended using 150 ml of liquid detergent in 100 l water, to allow the fiber to sink and absorb water over night. With NARA’s specifications in mind, we chose Cheer Free liquid detergent because it does not contain any optical brighteners, perfumes, or dyes. After rinsing the soaked fiber in an additional 100 l of water, we added it to 75 l water and 300 g lime—calcium hydroxide or Ca(OH)2—in a steam heated, stainless steel kettle and cooked for four hours. Cooking with lime and hard water helped us produce a slightly alkaline paper without needing to add buffering additives later.  We then drained the cooked fiber and added it to 120 l of water in a 25 lb. Jones Hollander beater. A drum washer was used to rinse the fiber with approximately 2000 l of water throughout the three-and-a-half hours of beating. After cooking we noticed small bits of seed and debris, called “pepper trash,” that cannot be eliminated during cotton processing without strong chemical bleaching. Fortunately, the mesh on the drum washer filtered out the majority of this during beating. Because the support paper for the Charters would require a great deal of planar stability but little in the way of strength, we were careful not to overbeat the fiber; in this way we avoided excessive shrinkage and expansion in the finished sheets. We used a Canadian Standard Freeness tester to maintain consistent beating, (230-270 CSF), from batch to batch.            When it came time to form the one hundred 36” x 36” sheets needed for the project, we encountered some hurdles. NARA had specified that half of the paper in the order needed to be 100 grams per square meter (g/m2)and the other half 200 g/m2. Maintaining this degree of accuracy with each sheet required careful measurement of the pulp. We checked the beater stock for consistency and then determined the quantity of pulp needed for each sheet. The pulp was then mixed with a whiz mixer before being measured for each sheet, to maintain consistency. To measure the pulp accurately, we fashioned a large graduated cylinder from a six inch diameter PVC pipe. The measured pulp was then added to 10 l of water and mixed again with a small mixer to avoid lumps in the pulp during formation.  We discovered that it was difficult at best—using a fast draining pulp without the aid of any formation additives—to produce a uniform sheet of large, book-weight paper that would meet NARA’s specifications. After considering a variety of more complicated devices, I designed a simple counterweight suspension system that offset much of the weight of the deckle box when it was full of pulp. Two ropes with weighted buckets suspended from pulleys were attached with hooks to either side of the mould. This made it easier to level and support the mould during formation. We held the deckle box down in a vat filled with 6” of water and mixed in the measured stock by hand. Two people then lifted the mould simultaneously and executed two large, slow shakes in each direction to evenly distribute the pulp, followed by successively smaller shakes until most of the water was drained. (This system proved to be so ergonomically beneficial that I later devised a one-pulley counterweight that we now use for the majority of UICB’s Western paper production.)             We couched the paper onto 100% wool felts (supplied by Chas. W. House and Sons Inc. of Unionville, Connecticut), until we had a post of twelve sheets. Couching book-weight paper this size did not prove to be any easier than sheetforming. To aid in aligning the mould and to minimize rounding the post, we stacked wooden strips along the leading edge of the pressboard. The mould could then be rested on these strips and positioned accurately before couching. The post was then pressed in the pneumatic press to 80 tons of pressure.  Most of the paper made at the UICB is loft dried, but because planar stability was essential for the NARA paper, we chose to dry it in the forced-air, restraint drying system designed by Lee S. McDonald. The pressed sheets of paper were placed between polypropylene felts, which were sandwiched between mesh-covered layers of corrugated material that allowed air to pass between them. These were alternated with occasional layers of rigid foam insulation to maintain flatness and were then covered with plastic, leaving the front and back sides open. The entire stack was cinched between heavy press boards and wooden beams using two tie-down straps tightened with ratchet mechanisms. A squirrel-cage style blower pulled air through the layers, drying the paper in about twenty-four hours. The finished sheets of paper were then weighed, sorted, and visually inspected before we selected the final hundred sheets for shipment.  At NARA, our paper then underwent extensive testing, including: visual analysis under magnification and ultraviolet light, pH testing using both hot and cold extraction methods, and determinations of alpha cellulose percentage and kappa number. In addition, Oddy and photoactivity tests were run on the paper.4 The UICB also provided NARA with samples of materials used as well as water quality test results that we had run before and during production. With this information, the conservators at NARA were able to identify and deselect any anomalous paper and use only the optimal sheets in the new encasements.  On September 15, 2000, page two of the Constitution was unveiled in its new encasement. Tim and I were fortunate to be invited to attend the ceremony, held in the Rotunda of the National Archives building, in Washington, D.C. While there we met with conservators and scientists from NARA and NIST, giving them a detailed account of the UICB paper production for the project. Although a great deal has been learned in the last five decades about the preservation needs of works on parchment, we were surprised to find that there was still considerable discussion about the ideal conditions inside the cases and the exact role our paper would serve. These experts hold differing opinions as to whether the cellulose helps stabilize the relative humidity within the cases, as was believed in the earlier encasement project. In the end, we were assured that at least one sheet of our paper would lie beneath each document.All of the Charters of Freedom will be temporarily removed from view on the 4th of July, 2001. The Rotunda will then undergo extensive renovations while the remaining documents are installed in their new encasements. Although an exact date has not yet been set, all eight pages of the Charters of Freedom should be back on display early in 2003.5 For the past fifteen years, the UICB has sought to bring together in the fields of books and paper valuable information from the past with the best innovations and technology of the present. We gratefully acknowledge the generous contributions made by many people over the years and welcome the opportunity to share this information with others in these fields. But efforts like the Charters of Freedom project, which are also of great significance to the public, offer the added bonus of fostering greater understanding and support within the mainstream population for ongoing research and production. The Charters of Freedom project illustrates the beneficial impact that collaboration between conservators and craftspersons, scientists and historians, and artists and engineers can have on the preservation and accessibility of the precious and irreplaceable artifacts of our culture.  Notes1. For additional information on the handling of the Constitution over time, see The Constitution of the United States together with an account of its travels since September 17, 1787, by David C. Mearns and Vernon W. Clapp, The Library of Congress, Washington, 1948, printed by the Government Printing Office.2. “Preservation of the Declaration of Independence and the Constitution of the United States,” National Bureau of Standards Circular 505, issued July 2, 1951.3. ibid., page 13. The sheets were “to be used to back up the documents and to serve as a humidity reservoir to offset any changes in the water-vapor content of the atmosphere in the enclosure resulting from temperature variation.”4. NARA test results on UICB paper, provided by R. Panayappan, Research & Testing: “The pH done by cold extraction was 9.62, the pH by hot extraction averaged 6.85 (it is not unusual for the hot extraction pH to be more acid than the cold). In keeping with the method of manufacture, the alkaline reserve was low, 1.3%. The alpha cellulose was high, 98.8%, and the kappa number, a measure of the amount of unbleached material, in this case lignin from the seed cases that were in the cotton fiber, was 1.9. This is well in line with the kappas we got for fully bleached wood pulp paper and board which were submitted as lignin free. The paper passed both the Oddy test, which looks at emissions that tarnish silver, lead or copper, and the photoactivity test, which checks the material in question against a colloidal silver detector (which may fade or get dark depending on the reaction) and a gelatin stain detector.” For comparison, the papers made for the 1950s encasements tested as follows (according to NBS Circular 505, cited above)—pH by cold extraction: 8.9; pH by hot extraction: 9.0; alpha cellulose: 92.0.5. For more information on the Charters of Freedom project, visit the National Archives web site at > http://www.nara.gov/charters_reencasement/charters/reencasement.html