The Bible and the Dead Sea Scrolls: The ... - josephprestonkirk

KNOX, EASTON, AND JOHNSTON 3
is determined by the relative reflectances of the ink characters and
parchment. Materials used as inks absorb most wavelengths of visible
incident light (and thus reflect little light); this is why ink appears “black.”
On the other hand, parchment in good condition reflects all wavelengths
of visible light well, and thus appears to be “lighter” in shade. The resulting
high contrast between characters and the background parchment
ensures that the document is easy to read.
Unfortunately, many ancient documents suffered damage during storage
that has darkened the parchment (by decreasing its reflectance). In
turn, this reduces the contrast between ink and parchment and hence the
readability as seen by the human eye in “visible” light. One of the ways
to increase the contrast of the parchment in the degraded regions is to
illuminate the text with “invisible” light, where the contrast of the text
may be better than what can be seen by the eye.
Because light is a wave, it is evident that wavelengths exist that are
longer or shorter than those visible to the eye. Waves just shorter than
visible blue light are classified as “ultraviolet,” while still shorter waves
range to the very short X-rays. Waves just longer than visible red light
constitute “infrared” light, and the length may be increased still farther to
radio waves. “Invisible light” at these other wavelengths often conveys
information about the object that is not apparent to human eyes. For
example, the temperature of an object is the primary determinant of the
amount of light measured in the “thermal infrared” region of the spectrum,
where the wavelength is approximately twenty times longer than
the eye can see. Until fairly recently, the best example of a technology for
creating images using these “invisible” wavelengths was infrared film,
which was developed during World War II and has been applied to
forensic imaging tasks, including imaging of the Dead Sea Scrolls.
However, modern sensor and imaging technologies now make it possible
to create images over a wide range of “invisible” wavelengths, making
possible what is now called “multispectral” imaging.
TRENDS IN MODERN IMAGING AND COMPUTING TECHNOLOGIES
The capabilities of both digital computer and imaging technology have
exploded in the last decade or so, and largely for the same reasons: the
advances in the microelectronics industry. Imaging systems are available
now that combine portability with capabilities that were barely imagined
only a few years ago. A primary example is the digital camera; relatively