The art of detecting forgery or fraud, in checks, drafts, documents,
seals, writing materials, or in the characters themselves is a study
that has attracted handwriting experts since its study was taken up.
There are almost infallible rules for the work and in this chapter is
given several new methods of research that will prove of the utmost
value to the public.
It is not an uncommon occurrence that wills and other public documents
are changed by the insertion of extra or substituted pages, thereby
changing the character of the instrument. Where this is suspected
careful inspection of the paper should be made--first, as to its shade
of color and fiber, under a microscope; second, as to its ruling;
third, as to its water-mark; fourth, as to any indications that the
sheets have been separated since their original attachment; fifth, as
to the writing--whether or not it bears the harmonious character of
the continuous writing, with the same pen and ink, and coincident
circumstances, or if typewritten, whether or not by the same operator
or the same machine. It would be a remarkable fact if such change were
to be made without betraying some tangible proof in some one or more
of the above enumerated respects.
Books of accounts are often changed by adding fictitious or fraudulent
entries in such spaces as may have been left between the regular
entries or at the bottom of the pages where there is a vacant space.
Where such entries are suspected, there should be at first a careful
inspection of the writing as to its general harmony with that which
precedes and follows, as to its size, slope, spacing, ink, and pen
used, and if in a book of original entry, the suspected entry should
be traced through other books, to see if it is properly entered as to
time and place, or vice versa.
The judgment by the naked eye as to the colors or shades of two inks
in the same paper or document is very likely to be erroneous for the
reason that when a lighter ink is more heavily massed than a darker
one the effect on the eye is as if it were the darker. Under a
microscope or magnifying glass the field is more restricted, the finer
lines are broadened, and one has larger areas of ink to compare with
less surface of strongly contrasted white paper. Then, again, an ink
without noticeable bluish tinge to the naked eye may appear quite blue
under the glass where the films of ink are broadened and thinned and
their characters better observed.
In order to judge whether two marks have been made by the same ink,
they should be viewed by reflected light to note the color, luster and
thickness of the ink film. Many inks blot or "run" on badly sized
paper--i.e., the lines are accompanied by a paler border which
renders their edges less well defined.
Even on well-sized papers this class of inks usually exhibits only a
stained line of no appreciable thickness where the fluid has touched
The copying and glossy inks, which often contain a considerable
quantity of gum, do not "run" or blot even on partially sized paper,
and show under the glass a convexity on the surface of the line and an
appreciable thickness of the film.
It does not always follow when an ink has made a blur on one part of
the paper and not on another that the paper has been tampered with. A
drop of water accidentally let fall on the blank page will frequently
affect the sizing in that place, and, besides, all papers are not
evenly sized in every part.
The inks rich in gum, or those concentrated by evaporation from
standing in an open inkstand, give a more lustrous and thicker stroke.
Some inks penetrate deeper into the paper than others, and some
produce chemical effects upon the sizing and even upon the paper
itself, so that the characters can easily be recognized on the
underside of the sheet. In some old documents the ink has been known
to so far destroy the fiber of the paper that a slight agitation of
the sheet would shake out as dust much of the part which it covered,
thus leaving an imperfect stencil plate of the original writing.
Distilled water is very useful in many cases to ascertain whether
paper has been scratched and partially sized or treated with resin. If
it has not been altered by chemical agents, the partial sizing and the
resinous matter used give to the paper a peculiar appearance. Sizing
takes away from the whiteness of the paper, and, thinned by the
scratching or washing, it absorbs much more quickly even when it has
been partially sized.
A simple mode of operation is to place a document or paper suspected
of being a forgery, on a sheet of paper or better still, on a piece of
glass; then moisten little by little with a paint brush all parts of
it, paying close attention to the behavior of the liquid as it comes
in contact with the paper.
By means of water one can discover what acids, alkalis, or salts the
parts of the paper with colored borders or white spots contain.
With the aid of a pipette cover these spots with water and let it
remain for ten or fifteen minutes; then with the pipette remove the
liquid and examine the products it holds in solution. Afterwards make
a comparative experiment on another part of the paper which is neither
spotted nor whitened.
If the original writing has been done with a very acid ink on a paper
containing a carbonate, such as calcium carbonate, the ink, in
attacking the calcareous salt, stains the paper, so that if the forger
has removed the ferruginous salts this removal is denoted by the
semi-transparence that water gives to the paper.
To study carefully the action of the water it is necessary to repeat
the experiment several times, allowing the paper to dry thoroughly
before recommencing it.
According to Tarry, it is necessary to have recourse to alcohol to
discover whether the paper has been scratched in any of the parts and
then covered with a resinous matter to prevent the ink from blotting.
Place the document on a sheet of white paper and with a paint brush
dipped in alcohol of specific gravity 0.86 or 0.87 cover the place
supposed to have been tampered with. It may be discovered if the
writing thickens and runs when the alcohol has dissolved the resin.
Hold the paper moistened with alcohol between the eye and the light;
the thinning of the paper shows the work of the forger.
Some more skillful forgers use paste and resin at the same time to
mask their fraudulent operations; in this case luke-warm water should
be first employed and then alcohol; water to dilute the paste, and
alcohol to dissolve the resin. The result is that the ink added on the
places scratched out spreads, and the forgery is easily seen.
Test-papers (litmus, mauve, and Georgina paper) serve to determine
whether a paper has been washed either by the help of chemical agents,
acids incompletely removed, or the surplus of which has been saturated
by an alkali, or by the help of alkaline substances. The change of the
color to red indicates an acid substance; an alkali would turn the
reddened litmus paper to blue, and the mauve and Georgina test-papers
Take a sheet of test-paper of the same dimensions as the document to
be examined, moisten it, and cover it underneath with a sheet of
Swedish filter-paper. These two sheets together (the filter-paper
underneath) are then applied to the document which has been moistened
already. The whole is then laid between two quires of paper, covered
by a weighted board, and left in this condition for about an hour. At
the end of this time examine the test-paper to see if it has partly or
altogether changed color. This examination finished, put the
test-paper in contact with distilled water, to be afterwards removed
and tried by appropriate tests to discover the nature of the alkali or
Silver nitrate is also used to discover whether the paper has been
washed with chlorine or chlorites. A paper in that way becomes acid.
The chlorine changes to hydrochloric acid, which dissolves in the
water with which the suspected document or paper is moistened, and at
the contact of silver nitrate little spots of silver chloride appear.
There are various other tests such as gallo-tannic acid or infusion
of nutgalls prepared a short time before application and may be used
with advantage to restore writings that have been removed by washing.
Place the document or paper on a sheet of white paper and moisten the
whole of its surface with a paint brush dipped in the reagent, taking
care not to rub it or strongly press it. When the surface is well
impregnated allow the solution to act for an hour, and at the end of
this time examine the document again. Then moisten it a second time
and the following day, examine the results. Repeat the moistening
several times if necessary, for it often takes some time to make the
traces of writing reappear.
Chevallier and Lassaigne experimented together on the effect produced
by the vapor of iodine on the surface of the papers or documents upon
which the alteration of writing was suspected. Take a bottle with a
wide mouth from ten to eleven centimeters in height, and the opening
from five to six centimeters in width. This last is covered by a disk
of unpolished glass. Into the bottom of this vessel introduce from
twenty to thirty grams of iodine in crystals.
Place the portion of paper on which the vapor of iodine is to act at
the opening of the bottle, and cover it with the stopper of unpolished
glass, on which put a weight so as to exert a slight pressure, and in
order that the aperture may be hermetically closed. Then allow the
vapor of iodine to act on the dry paper for three or four minutes at
the temperature of 15 deg. to 16 deg. C. and examine it attentively. When the
surface has not been spotted by any liquid (water, alcohol, salt
water, vinegar, saliva, tears, urine acids, acid salts, or alkalis) a
uniform pale-yellow or yellowish-brown tinge will be noticed on all
parts of the paper exposed to the vapor of iodine.
Otherwise a different and easily distinguished tinge shows itself on
the surface that has been moistened and then dried in the open air.
Machine-made papers with starchy and resinous sizing give such decided
reactions that sometimes it is possible to distinguish by the color
the portion of the paper treated with alcohol from that moistened with
water. The spot produced by alcohol takes a kind of yellow tinge; that
formed by water becomes a violet blue, more or less deep, after having
dried at an ordinary temperature. As to the spots produced by other
aqueous liquids, they approach in appearance, though not in intensity,
those occasioned by pure water. Feeble acids, or those diluted by
water, act like water; but the concentrated mineral acids, in altering
more or less the substance of the sizing, produce spots that present
Spots which become apparent by using vapor of iodine are due to
chemical agents whose strength has altered either the fibers of the
surface, or the paste uniting them.
In a word, the test of a document or paper by vapor of iodine has the
double advantage of indicating the place of the supposed alteration
and operating afterwards with appropriate reagents to bring back the
traces of ink. It is only the reappearance of former letters or
figures written or effaced that demonstrates forgery. Much time may be
profitably spent in merely scanning each letter of a document, and the
writing by lines, paragraphs, and pages before a closer scrutiny.
Gradually, if the writing be genuine, its character will begin to
reveal itself, and unconsciously a hypothesis as to the physical
causes of the irregularities or characteristics will be formed.
When an entire document or page is forged, the ornamentation,
flourishes, or the capitals at its head will often be seen to be out
of keeping, either with its nature or with the supposed author's
habits in similar cases. In a writing all must agree, place, day,
year, handwriting, superscription or heading, signature, and material
carrying the writing, especially paper, both as to constitution and
color and ink.
See illustrations of various kinds of handwriting at end of this book.