[ Pobierz całość w formacie PDF ]
receive the greatest weight for identification purposes. By being familiar with hand-
writing systems and features written by many writers, he is able to determine which
features meet the criteria. There are two kinds of features: class and individual. Class
features are those derived from the general style to which the handwriting conforms10
and are the result of the writing system and other factors surrounding what the writer
learned as a child. They may also be the result of features found in a large number of
different writers writing. Because such features are common to a large group of
© 2000 by CRC Press LLC
writers, they have only a limited amount of significance in handwriting identification.
Individual features of writing have been introduced into the handwriting, consciously
or unconsciously, by the writer.10 These features may be unique, unusual, or rare and
usually are found in the writing of a particular person. Because of their rarity, they
are more important for identification purposes.
It is the combination of these class and individual features in sufficient quantity
that will lead the examiner to conclude that two writings are of common authorship.
How many are required? There is no set number required by any competent, quali-
fied, and ethical examiner, certifying board, or technical organization. That is why the
requirement for an identification is worded the way it is.
Writing Instruments
There are many different writing instruments, and each has its own unique charac-
teristics when used on different surfaces. Some of these writing instruments are
ballpoint pens, roller balls, fountain pens, pencils, crayons, or soft marking pencils. It
is important for the examiner to be familiar with these different writing instruments,
to know how they work and the markings they leave on different writing surfaces.
Inks
There are many different kinds of inks — writing inks, printing inks, etc. — which
vary not only in color but also in their use and chemical formulation. These differ-
ences also apply to how each of the inks behaves on a different surface. The FIC
receives special training to perform this work, but the examiner must have a basic
working knowledge of inks to recognize when the service of an ink chemist is
required.
Correction Fluid
Correction fluids are solvents used to remove or bleach ink so it will not be seen on
the paper or writing surface. Different solvents react differently to ink formulations,
chemicals in the paper, etc. Solvents that are a mixture of common household
chemicals, commercial ink eradicators purchased from a store, or even uncommon
chemicals such as brake fluid, etc. have been used to remove or bleach writing ink.
The examiner should have an understanding of some of these chemicals and their
reactions.
Correction fluid has been called the secretary’s best friend and is frequently used
to cover over typed or written material or an incorrect entry or to smooth out paper
fiber disturbances resulting from mechanical abrasion, etc. If a document is altered
using correction fluid, the examiner must know how to remove it without damaging
the information under it or how to make the correction fluid translucent so he can
see what is written or typed under it. Much work has been done in the area of
developing freezing techniques to remove or make correction fluid translucent and
micro-manipulation techniques to remove the correction fluid from the paper sur-
face. Micro-manipulation is the process of physically removing the dried correction
© 2000 by CRC Press LLC
Primary Line
Shadow Line
Figure 2. Effect of the ball housing of a pen creating a secondary line on NCR paper. The same
effect can be found, but as an indentation, on a sheet of paper. If this effect is not properly
evaluated, the writing may be mistaken for an indented outline tracing. A great deal of caution
is necessary in the evaluation of this or any feature of a document.
fluid from the document’s surface without damaging or destroying the material
beneath it. Recovery of the material beneath correction fluid is the primary goal of
this examination.
Copies and Copiers
There are many different types of material and processes used to make copies of
documents: carbon and non-carbon (NCR®) paper, multiple copier printers, photo-
copiers, etc. Each has its own unique properties and challenges for the examiner. It is
important for the examiner to be able to recognize what type of copy he is dealing
with, how it is made, and whether it can be altered. Each type of process offers its own
set of problems and cautions. For example, when a writer signs NCR® paper holding
a writing instrument at too steep an angle to the paper surface, the following can
occur: The ball housing of the pen drags on the paper as the writer is writing, which
sometimes results in an indented shadow line on the original document and a dark
line on the copies paralleling and intersecting the primary writing line as in Figure 2.
This figure illustrates the effect of a ball pen housing creating a secondary line on a
NCR® paper copy. The same effect can be found, but as an indentation, on a sheet of
paper. If this effect is not properly evaluated, the writing may be mistaken for an
indented outline tracing. A great deal of caution is necessary in the evaluation of this
or any feature of a document.
The shadow line appears as an outline following and intersecting with the
primary line. The assumption is made here that the writer of the material in Figure
2 is righthanded. Typically, with righthanded writers, this shadow line will be on the
right side of a downstroke and on the left side of an upstroke. Even though Figure 2
does not show this phenomenon exactly, it does illustrate that a shadow line can be
present on both the original and a copy, and when it is present, its cause must not be
misinterpreted. The effect of this dragging, as mentioned above, has on occasion been
© 2000 by CRC Press LLC
[ Pobierz całość w formacie PDF ]