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Saving the Dead Sea Scrolls for the Next 2000 Years, Dodo Joseph Shenhav, Biblical Archaeology Review, Jul-Aug 1981.

InkwellThe Dead Sea Scrolls were preserved in remarkable condition for 2000 years in the Qumran caves overlooking the Dead Sea. It seems almost a miracle that these caves in which the Essenes stored their scrolls were very nearly the perfect environment for the preservation of the documents.

Despite the capabilities of modern science, it is difficult, if not impossible, to reproduce precisely this environment in a Jerusalem museum. Although only a thirty-minute drive from Qumran, Jerusalem is 2500 feet above sea level, while Qumran is about 1300 feet below sea level. Jerusalem has 20 inches of rain a year, compared to one or two inches in the Judean Wilderness of Qumran. But even if we could recreate the Qumran caves our problems would not be solved.

Before the scrolls arrived at the museum, the bedouin who discovered them and the merchant middlemen who bargained with the scholarly world for their purchase, exposed the scrolls to a humid environment from which they absorbed moisture. This upset a 2000-year equilibrium and irreversibly altered the parchment on which the scrolls were written.

Early analysis of the scrolls revealed that their parchment was made from untanned sheepskin – Not even a trace of tanning materials has been found on them. This is an important factor in explaining how the scrolls were preserved for 2000 years in the caves, because tanning materials frequently cause deterioration of parchment over long periods of time.

The Essene’s choice of ink was also fortunate. Most of the scrolls are written in a carbon ink made from soot or lampblack. Gum arable, a liquid adhesive, was added to stabilize the carbon ink. Lampblack is an inert and very durable substance. Unlike most modern inks which fade and even disappear after a few decades, the ink on the Dead Sea Scrolls has remained dark and legible for more than twenty centuries.

Not all of the Dead Sea Scrolls were written with this ink, however. For example, the scroll known as the Genesis Apocryphon was written in an iron gall ink which includes gallotannic acid. Over the ages the acidity of this ink ate away the parchment. As a result, this scroll came to us in a much more deteriorated condition than the scrolls written in carbon ink, and the task of deciphering the Genesis Apocryphon was correspondingly more formidable.

Aside from the parchment and the ink, the single most important factor accounting for the extraordinary preservation of the scrolls is the climatic condition of the caves in which they were stored. The air there is extremely dry, the temperature is stable within very narrow limits, and there is almost no air flow within the caves. When the scrolls were placed in the caves, they dehydrated gradually and soon reached a state of almost perfect equilibrium with the environment which surrounded and protected them. Moreover, the same climatic conditions which favored the preservation of the scrolls prevented the growth of harmful bacteria which might otherwise have caused them to decompose.

When the scrolls were removed from the caves, this equilibrium was permanently and irreversibly destroyed. How much damage to the scrolls occurred between the time they were taken from the caves and the time they arrived at the Israel Museum, we have no reliable way of knowing. We do know that sharp and sudden changes in the climatic environment of ancient artifacts composed of organic materials can cause almost instant disintegration, despite the combined efforts of archaeologists and professional conservators. For example, a drop of water can immediately gelatinize a piece of dessicated parchment or leather. Sudden dryness will cause cracks in wood.

Parchment is hygroscopic—that is, it readily absorbs and retains moisture from the air. If exposed to humid air for an extended period of time, the parchment will simply decompose. Gradually, the parchment takes on a gelatinous quality and turns into a brownish, tacky, semi-fluid substance. When the scrolls arrived at the Israel Museum, some already exhibited signs of initial disintegration of this kind. Others were in various stages of gelatinization.

Obviously the preservation of these scrolls presented special problems. The overall task of preserving the scrolls has not been a easy one. We began by seeking information and advice from conservators and scientists through’ out the world. We worked closely with the late James Bieberkraut of Jerusalem who in 1955 had opened the Genesis Apocryphon. Bieberkraut was especially helpful in connection with techniques for opening the scrolls. We sent parchment samples for analysis to the Leeds Laboratory in England, to the British Museum in London, to the Patrimoine Artistique in Brussels. We invited the director of UNESCO’s Department of Conservation, Dr. H.J. Plenderleith, to come to Jerusalem for consultations.

We also undertook our own studies in the Israel Museum laboratories. Here we developed a solvent to enable us to remove the glue and tape which someone had applied to the scrolls before they arrived at the museum. We also produced an adhesive suitable for affixing scroll fragments which fit together.

Our most important task, however, was to create a suitable climatic environment for the scrolls. Because the scrolls had, to a certain extent, already “adapted” to a climate far different from the one in which they had survived for 2000 years, our aim was not to reproduce as precisely as we could the climate of the Dead Sea caves.

One possibility we considered was to encase the scrolls in an inert gas like helium or nitrogen. The American Declaration of Independence is preserved in this way. We tried this method with one of the scrolls, but technical difficulties finally convinced us that this method was impractical for such a large quantity of documents. Moreover, we found that some strains of bacteria, which are anaerobic (that is, were able to live without oxygen), might multiply even in inert gas.

In the end, taking into account the recommendations made by a variety of experts, but especially those by Dr. Plenderleith, we decided to keep the scrolls in an environment with a constant temperature of 19° C (66° F) and a constant relative humidity of 55%. In the display halls, the temperature is permitted to vary only ±.02° C; in the storerooms, a variation of only ±.05° C is permitted. Similarly with respect to humidity variations, we try to maintain a relative humidity in the display halls which varies ±3%, but in the storerooms, only ±1%.

Scrolls that had begun to gelatinize are kept in small chambers of polyethylene in which the relative humidity is maintained at 40%. In this way, we dry off the parchment and keep it stable.

Light was another problem. All light, but especially ultraviolet rays, will in time decompose organic materials. Our display halls therefore use no natural light. The sparse artificial light is filtered to eliminate wave-lengths within the ultraviolet range. The minimum amount of light required for the movement of visitors is permitted.

Even in the display cases the light is limited to 50 luces, which is equivalent to a 25 watt bulb at a distance of two feet. To reduce further the scrolls exposure to light, automatic timer buttons have been installed in each display case. To turn the light on, the viewer must press a button which provides a dim light for 50 seconds.

Inside the display cases, the scrolls have been placed between two sheets of silk stretched over a plexiglass frame. This permits the parchment to “breathe”, that is, to adapt even to scant changes in temperature and humidity which might cause slight changes in the volume of the scroll. In this way, cracking is prevented. The plexiglass frame is covered with plexiglass sheets, the back one of which is perforated to permit air-flow, thus preventing moisture condensation.

Although the light in the display halls is kept to a minimum, it is obvious that no light whatever would be better. The price then would be to remove the scrolls from public display. Every museum is confronted with this dilemma- The optimum conditions for preservation of delicate materials preclude public display, but the public wants and has a right to see. Some have argued that the original Dead Sea Scrolls are so delicate and so important that they should be kept only in storerooms. Those who hold this view suggest that facsimiles are adequate for public display. Others argue that under controlled museum conditions, the original scrolls can be displayed without any significant deterioration occurring.

The Israel Museum’s Shrine of the Book has decided on a middle ground- Only stable scrolls in a good state of preservation are exhibited. If we find even minor signs of deterioration, the scroll is kept in the storerooms.

Several years ago, we replaced the 24-foot-long Isaiah scroll, which is the central exhibit in the main display hall, with a facsimile. We took this action for two reasons – First, the large central drum around which the scroll was rolled required the scroll to be bent backwards, contrary to the curve in which the scroll had been rolled for 2000 years. To eliminate the possibility of the scroll cracking eventually, we thought it best to remove this centerpiece of our Dead Sea Scroll display and replace it with a facsimile. Second, we discovered that this Isaiah scroll was especially sensitive to the light which continuously illuminated its display case during museum hours. This simply confirmed our painfully reached decision to put the original in the storeroom. The Isaiah scroll, however, is the only facsimile displayed in the Shrine of the Book.

The Israel Museum’s Dead Sea Scrolls are a unique treasure and belong not only to those of us now living but also to future generations. We at the Museum have tried our best to meet our responsibilities both to the present generation and to those who will come after us.

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