|Here is a sampling of some of the tools we use.
Scanning Electron Microscope
provides the capabilities of increased magnification for analysis of particulate evidence,
paper fibers or the intersection of written lines to determine sequence of
preparation. The increased capability of x-ray analysis allows for characterization
of a variety of evidence including paper, ink, toner and pencil. This
characterization allows for a determination of common origin or source.
Fourier Transform Infrared
Spectroscopy is a molecular spectroscopy which is used to characterize both
organic and inorganic evidence. Its uses range from differentiation of toner
samples, which indicates the use of multiple xerographic machines, to the detection of
specific inorganic components in paper or pencil, which would aid in the determination of
The Atomic Force Microscopy
allows for discrimination of surface features at the atomic level. This methodology
is useful for the determination of line sequence and the characterization of surface
features such as staple marks, creases in paper or other irregularities in the paper
X-ray Photoelectron Spectroscopy
is an atomic spectroscopy which is capable of elemental and molecular information.
It is used for the characterization of toner materials and can give information regarding
the age of xerographically produced documents.
Thin Layer Chromatography
is a separation technique ideally suited to the characterization of ink, carbon,
typewriter ink and other materials containing colored components. TLC is used routinely to
differentiate between ink formulations and to identify the specific manufacture of an ink
which appears on a questioned document.
Spectrophotometry, or Densitometry is a quantitative technique which is used
to determine the relative amounts of components present in inks, or the extraction
characteristics of a given written entry. This information can help determine the number
of different writing instruments used to prepare a given entry or the relative age of an
entry in comparison with other writings.
Electrostatic Detection Apparatus is a
methodology used to detect and visualize the indented impressions present on a page of
paper. These impressions are the result of the preparation of writing on a document while
in contact with the examined page of paper. The content of indented impressions and the
identity of their source can allow for the determination of the sequence of preparation of
different documents. Therefore an out of sequence document can be shown to have been
prepared at a time different from its date.
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