Handwriting Analysis
One of the oldest investigative sciences is handwriting analysis. People have
been forging wills, bank drafts and cheques ever since their invention. Police also
study handwriting in connection with hold-ups, ransom and suicide notes.
Experts were not accepted in this field until the late 1800s, but even with expert
testimony, it was difficult to convict a person without a confession. It wasn’t until
2002 that anyone published a convincing study proving the scientific utility of
handwriting analysis. Sargur Srihari, of the State University of New York at
Buffalo, looked at 1,500 U.S. handwriting samples. Through computer analysis of
10 specific characteristics, the researchers established that it was possible “to
determine the writer with a high degree of confidence.”
It should be noted that forensic document examination (or questioned document
examination, as it is commonly known) is frequently confused with the field of
graphology. Graphology is the study and analysis of handwriting especially in
relation to human psychology. Graphologists have been employed to
understand the psychology of criminals, including serial killer Ted Bundy, but
critics of the profession question the lack of empirical evidence in the field.
The Calgary Police began studying disputed handwriting at the turn of the
century but have always had to rely on experts to present the evidence in court.
Early experts were either self-taught or were bank tellers, lithographers or
teachers of penmanship. Now Forensic Document Examiners (FDE) are known
and respected professionals, with specific training standards comprising of two
years of study plus a university degree. The field is still a rather small segment of
the forensic science field and university programs are rare. Most of the training is
done as an apprenticeship with an experienced document examiner. FDEs
examine questioned documents (QD) from samples of handwriting to computer
printouts and other typed samples.
Handwriting analysis is particularly useful for cases that involve forgery. Forged
signatures are studied for style, angle and pen pressure. Allowances are made
for writing conditions, such as space, purpose of signature, paper, writing
instrument and changes in mood or age. Forgeries are often traced and will have
gaps or pauses in the connecting lines. They will be studied in appearance and
are usually longer in final length. In order to compare a forged signature, it is
necessary to obtain a sample of the suspect’s handwriting. This is best
achieved if the suspect is unaware of the purpose of the sample. Since 1938,
the RCMP have employed scientists to work in the document section of their
forensic laboratories. Forensic science is the use of scientific techniques to
study evidence that will then be used in a court of law.
Scientists working in the document section study samples of handwriting,
typewriting and computer printouts. Experts can often tell the make and model of
a computer printer based on data collected from studying all of the makes and
models ever made. The characteristics of a certain make or model of printer are
determined in the factory and include printing style amongst others. These are
called class characteristics. After use, computer printers acquire their own
unique characteristics such as spacing or damaged typeface. These are called
accidental characteristics and are used to identify a specific printer. A sample of
text from the suspect’s computer printer is obtained by the police and compared
to the evidence sample. Comparison is used to make an exact match. The two
samples must match on a variety of characteristics.
The work of identification officers accepts the basic principle that no two things
are ever exactly alike. Just as no two people are exactly alike, no two objects are
exactly alike. Factory made objects may look exactly alike, but there is usually
some difference that is noticeable upon closer inspection. With use, even more
differences occur.
Let’s analyze you! Copy the following sentence in printing and cursive:
The shy fox jumped quickly over the brown lazy dog.
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Think about the following questions as you consider how you would check a
piece of work with no name on it to see if it was yours:
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Does your own printing/handwriting always look the same?
Do other people consistently form letters the same way?
Which letters are the easiest to spot differences in?
Which letters are more difficult?
Observations
Inference
Chromatography - Definition
A method of separation and
analysis of a mixture of soluble
chemical substances.​
What is paper
chromatography?​ Paper
chromatography is a method that
is used to separate out materials
from a mixture. A solvent such as
alcohol or water is used to
dissolve the components of a
mixture. The solvent travels up
the paper by capillary action. The
particles of solute that are
dissolved in the solvent are
carried up the paper along with the solvent. The particles of solute will be
separated according to size as they are carried up the paper; the smaller
particles travel faster and will end up at the top, while the larger particles will
travel more slowly and will be seen at the bottom. The pattern on the
chromatography paper is called a chromatograph.
Chromatography is used to separate and identify all sorts of substances in
police work. Drugs ranging from narcotics to aspirin can be identified in urine
and blood samples, often with the aid of chromatography.
How does it work?​ ​Paper chromatography is a technique that involves
placing a small dot or line of sample solution onto a strip of chromatography
paper. The paper is then placed in a jar containing a shallow layer of solvent
and sealed. As the solvent rises through the paper, it meets the sample
mixture which starts to travel up the paper with the solvent.
Several factors explain why the different parts of the mixture separate out as
they do:
1.​ ​ ​Solubility​: If the components of the mixture are dissolvable in the
liquid being used, the mixture will be carried up the paper strip as the
liquid travels. If the material is soluble, the mixture will dissolve as
the solvent front moves through it. If the material is a mixture of
substances, some of these substances will likely be more or less
soluble than others. The more soluble substances will move faster
and to a greater distance than those that are less soluble.
2.​ ​Molecular Weight​: Those substances of lighter molecular weight will
move higher up the paper than those substances having a higher
molecular weight.
The experiment we do in class will demonstrate the use of paper
chromatography to separate out the colors in the ink of water-soluble markers.
A combination of colored dyes is often used to create black ink. Since the inks
are water-soluble, water can be used as the solvent to dissolve the ink and
separate out the colors. Different brands of markers use various combinations
of colored dyes to make up black ink. These dyes create distinctively colored
patterns, or chromatographs, when they are separated by chromatography.
What can Chromatography be used for?
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Identify additives in foods
Compare fibres found at a crime scene
Identify drugs & alcohol
Test water samples for pollution
Detect bombs in airports
Detecting pesticides or insecticides in food
Fingerprinting