Page 10 - 2022UNESCO ICDH Newsletter_vol.4

After the scanning and imaging process,
elemental XRF maps are obtained by raster
scanning the object with a small X-ray beam. The
advantage of synchrotron-based imaging over
commercial systems is X-ray beam polarization
to reduce scattering background, tunability of the
X-ray energy, enhanced spatial resolution, larger
focal depth (ensuring that uneven objects stay in
focus) and faster scanning speed due to the larger
flux. Over the past decade, numerous studies have
demonstrated the viability of XRF mapping to reveal
elements from writings in paper or parchment
manuscripts and other large objects.
analysis of material composition. To briefly explain Elemental maps from the unique features of the
the process of XRF, a sample is irradiated with a paper and prints in these bound paper books will
very high-energy of X-rays beam from the energy combine chemical composition analysis with spatial
source. In this case, is the synchrotron. When the information. Based on the findings in the elemental
X-ray beam strikes the sample, particularly an atom, maps, quantitative point analyses are conducted
an electron from one of the atom’s inner orbital on selected areas of each folio. The combination
shells is dislodged. The atom regains stability, of elemental maps and point analysis offers
filling the vacancy left in the inner orbital shell with information on the components of the typeface and
an electron from one of the atom’s higher energy ink, as well as the paper. This information allows
orbital shells. The electron drops to a lower energy the researchers to assess any chemical similarities
state by releasing a fluorescent X-ray. The energy and differences across entire paper pages between
of this X-ray is equal to the specific difference in early Korean books and European books.
energy between two quantum states of the electron.
The measurement of this energy is the basis of XRF
[1]
analysis , providing data for the elemental XRF
maps.
The XRF analysis and imaging method that was
used for this research has great potential to reveal
unique information about the lead-alloy metal types
and inks used in early printing materials from Korea.
The team employed XRF imaging and pointed
analysis to determine the elemental composition
of the inks and paper with potential traces of the
type metals in 14th to 19th-century printed books
using cast-metal type. Comparing the trace metal
concentrations and spatial distributions in the ink
and paper of these books critically contributes
to the team’s understanding of the printing and
typecasting methods used in this early information
technology.

[1] Thermo Fisher Scientific. (2020. What is XRF (X-ray fluorescence) and how does it work? Ask a Scientist.
from https://www.thermofisher.com/blog/ask-a-scientist/what-is-xrf-x-ray-fluorescence-and-how-does-it-work/(2020)

10 UNESCO ICDH Newsletter 11 Memories of Today