IN 1970 archaeologists digging at Ein Gedi, an ancient settlement on the shores of what is now called the Dead Sea, dug up the ark of a synagogue that had stood on the site from about 800BC until it was destroyed by fire in around 600AD. Within was a trove of scrolls but sadly, though the ark had protected them from the worst of the blaze, they were badly scorched. They were, indeed, so damaged that any attempt to handle them simply made things worse. That left archaeologists with a cruel dilemma: attempt to read their discoveries, which would destroy them, or preserve them as found, but remain ignorant of what they said.
Technology, however, marches on. In a paper just published in Science Advances, a team led by William Seales, a computer scientist at the University of Kentucky, describe how they have managed to read one of the charred scrolls without having to open it—or, indeed, to touch it at all.
The first part of Dr Seales’s remote-reading method was to take an X-ray of the scroll—or, rather, multiple X-rays from different directions that could be combined by a computer into a three-dimensional representation of the scroll’s interior. This is a well-established procedure. It is, for example, the basis of medical CAT scanning. The real wizardry came when the 3D image was fed into a series of computer algorithms that attempted to “unroll” the scroll virtually, leaving it to be read at an archaeologist’s leisure.
To do this, the algorithms in question had to perform several tricky tasks, the first of which was to work out, purely from the swirling shapes present in the 3D model, how to distinguish particular layers of a rolled-up scroll from those above and below. In the case of the Ein-Gedi scroll, that was made harder by the fire, which had damaged individual layers unpredictably.
This done, the next step was to look for subtle density variations that might correspond to the presence or absence of ink—and thus reveal individual letters. The final task was to take the hundreds of small images spat out by the algorithms and stitch them into a single, larger one. This was a matter both of science and of art. The algorithms got the jigsaw right only half of the time, meaning people had to do much of the work by hand.
The result, though, was worth the effort. The outcome of Dr Seales’s labour is a computer image showing the scroll as it would look if it were unrolled (see picture). The resolution is so good that the text is easily legible, as are the guidelines scored by its scribe. The scroll, which was written around 200-300AD, turns out to be part of Leviticus. It is thus the oldest known example of one of the books of the Pentateuch, the first five books of the Bible.
A tour de force, then—and not, Dr Seales hopes, a one-off. His technique should be usable on other damaged scrolls, of which archaeologists have plenty. Besides those recovered from Ein Gedi, there is, for example, the trove found in the library of a villa in Herculaneum, a Roman town that was destroyed by an eruption of Vesuvius in 79AD. Similar techniques to Dr Seales’s have read parts of some of these, but no one has yet “unrolled” one in its entirety. Other objects, such as lockets or amulets that have written messages (of love, perhaps, or prayers or magical spells of protection) inside them, should be suitable too. There is even a rumour that America’s spooks are interested. It is not only archaeologists who might want to read something without opening it.