Multispectral Imaging Reopens Old Texts
Brent D. Johnson
Our record of Western antiquity is a piecemeal assemblage of oral traditions, myths and scattered clues from gravestones, road markings, coins, civic monuments and pottery shards. This dearth of a coherent body of literature to describe what life was like in the past leaves scholars scavenging the rubble of destroyed cities to find some shred of evidence.
From left to right, Steven Booras, Daniel Oswald and Susan Booras use multispectral imaging to analyze a carbonized scroll fragment.
Investigators at Brigham Young University have developed an imaging system that could radically change our understanding of history. By lifting previously unreadable text from ancient scrolls, the team is resurrecting moments from our collective history.
For years, Steven Booras had worked with the Dead Sea Scroll database, using slides from the Ancient Biblical Manuscript Center. Then Greg Bearman applied a multispectral imaging system developed by NASA's Jet Propulsion Laboratory in Pasadena, Calif., to the scrolls. Through his association with Bearman, Booras came to use the technology, made some improvements and streamlined it for use in the field.
While there is no trace of the text under visible light (right), the ancient writing appears in the infrared (far right). The images of the scroll have been enhanced to show the original color; their actual color is charcoal black. Scroll images courtesy of Mark Philbrick.
The imager uses a Kodak 6.3i Megaplus camera from Redlake MASD Inc. of San Diego and standard Nikon lenses. But the heart of the system, Booras said, is its filter wheel, which was designed with the assistance of the university's college of engineering. This innovation allows the user to rotate through a series of bandpass filters covering the 400- to 1000-nm range.
The team first traveled to the ruins of Bonampak in southern Mexico near the Guatemalan border, a site that represents the peak of Mayan civilization in the Late Classic period of A.D. 600 to 900. Using the multispectral imager, it found glyphs in Bonampak's renowned murals that had never been seen before.
Bolstered by this success, the researchers were invited to Herculaneum, an ancient city southeast of Naples, Italy. Buried since the eruption of Vesuvius in A.D. 79 and scorched by its pyroclastic flows, volumes in the city's library appear to have been reduced to charcoal briquettes. Under the institute's imaging system, however, they become legible.
The team has achieved the best results in the 950- to 1000-nm range. Approximately 90 percent of the Herculaneum scrolls respond to these wavelengths, while only 1 to 2 percent respond at 400 nm. The researchers attribute this to the use of a vegetable-based ink.
Booras said he finds it ironic that the cataclysm that destroyed the library actually preserved the scrolls. All other papyrus scrolls from this time have turned to dust, he noted, but the burned scrolls can still transmit information.
The ability of this technology to decipher ancient texts could open another chapter in the history of the ancient world.
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