Improved Means for Preventing the Falsification of Documents, Bills, and the like.
Year: 1886

page_text: Improved Means for Preventing the Falsification of Documents,
Bills, and the like.
JULES ALBERT SCHLUMBERGER, Chemist, of 1 rue Bausset Paris in the Republic
of France do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement:―
The object of my improvements is to prevent commercial and other documents
from being falsified, forged or altered, and also to afford a means of ascertaining the
genuineness of the same, through the use of the chemical reactions of certain salts.
My method, which I may term a method of Cryptography,' consists in so
preparing the print, the inks and colours, or the paper, that any attempt at fraud
may become and remain evident, and that, on the other hand, the interested parties
themselves should be enabled to control or test the documents in a reliable and
efficient manner, so as to ascertain their authenticity.
Thus, in a cheque, bill, Post Office Order, etc. I form, by either lithographical
or typographic printing, a 'ground' in two or more shades of the same colour, but
of different nature. The consequence of my so doing is, that when the sheet thus
treated is submitted to the action of such reagents as are generally used for
decolouring ink, in order to remove one or more figures or signatures, and substitute
for them one or more other figures or signatures, one of the colours will vanish
away under the action of chlorine or some alkaline hypochlorite, while the other
colour or ink, remaining unchanged, becomes apparent in the shape of an indoliable
denouncing word, or conventional sign, which frightens the falsifer, deters him
from proceeding any further with his criminal work, and makes the circulation of
the forged document impossible.
If, for instance, the word 'forger,' printed in dotted or other characters by means
of cobalt blue, vermilion, lamp black, ochre, cadmium yellow or orange colour,
chrome, &c. &c. (which are all fixed colours), be combined with a second print, being
the ground of the engraving, and performed by means of aniline blue, cochineal or
aniline flame colour, indigo coloured madder lake, soluble aniline black, fustic orange
yellow, &c. (i.e. removable colours, which will not stand the action of decolouring
substances) it will be seen that the fugacious colour, in which the denouncing word
or sign is as it were drowned, and thus concealed from sight, may be totally

page_text: removed through a washing with chlore or any other decolouring substance,
whereas the dotted lines of the conventional sign or word, being drawn with a
fixed ink or colour, will remain unaltered and suddenly appear in a conspicuous
manner, thus either revealing a fraudulent attempt, or showing the genuineness of
the tested note or bill.
In order to render the delusion of any one unacquainted with the secret still
more perfect, I may embody to the fixed colour or ink some salt capable of
assuming, when it becomes visible,. a blackish bistre tinge, under the action of
oxydizing decolouring substances; thus sulphate or any other colourless salt of
manganese, or other similar salts, when imprinted on paper, will only become
visible upon having undergone the influence of an oxydizing agent; it follows that
cobalt blue, or any other fixed colour, with which sulphate of manganese or any
other salt having the same properties, has been mixed (such as cobalt salts for
instance), will appear in a blackish shade, so that the letters will thereby become
still more legible under the action of chlorine.
Another efficient means of detecting forgery consists in impregnating the paper
with a solution of manganese or other similar salt, such as chloride of cobalt
having the same properties in relation to oxydizing substances; if such paper be
thereupon brought into contact with chlorine or some oxydizing substance capable
of decolouring inks, a brown colour may result from the oxydation of the salt
applied to the paper.
I may also use inks or colours mixed with gummed water or oil varnish, and
containing colourless manganese salts, to prepare 'grounds' or form invisible
characters, so that a conventional word will appear whenever the paper is sought
to be manipulated with a malignant intent by means of oxydizing decolouring
agents. As the invisable parts of bills, cheques, bonds or other documents so
prepared cannot be photographed, it is obvious that photography can no longer be
used by falsifers as a means of fraud.
Interested parties may by the same means also control or test the authenticity
of documents. Thus through the use of any colourless salt capable of producing
inks normally invisible, but which become apparent by the action of a suitable
reagent, the test just alluded to is made as complete as possible, as an interested
party is thereby enabled to ascertain whether the conventional word or sign,-
which he is aware is affixed to genuine documents in one or more determined
points, is, or is not, in the right place. It will be understood that such
conventional signs may be numbers or letters describing the series or class of the
documents, and corresponding, if desired, with an index table previously drawn up
for the purpose.
The control or test of the authenticity of a document, by means of oil varnish or
gummed inks, may be effected":
By a print made on white paper with anhydrous sulphate of copper, the colour
resulting therefrom being blue when ammonia is used; black when brought into
contact with any one of the sulphurets, and brown when in contact with prussiate
of potash;
Or by a print made with invisible inks with a basis of yellow prussiate of
potash becoming visible if bathed with solutions of copper or iron salts; the latter
salt driving forth in the same manner inks, the basis of which is tannin;
Also by prints made with invisible inks, the basis of which is Phenol Phtaleine,
which, when brought into contact with alkaline solutions will produce a bright
pink colour. This means, however, is merely accessory or adjuvant by reason of
the colours, that become visible in this way, being capable of disappearing again
under the action of any acid, the same as some inks disappear as they cool, and
only become visible at a determined temperature: such are the sympathetic inks
the basis of which consist of certain salts of cobalt which have been well known
for a long time, but have never been applied in practise for the object herein
specified. Salicylate of soda or other salicylates, mixed with zinc white or other
white, also produce cryptographical inks, which become violet under the action of

page_text: chloride of iron. Through the use of these various means, whether singly or in
combination, fraud is rendered utterly difficult, if not absolutely impossible.
Some white or colourless salts, such as the salts of lead or bismuth, which
blacken when brought into contact with alkaline sulphurets, may also be applied ;
their action, however, is less certain and not so practicable.
Another means of preventing forgery, or 'novel' controlling method' consists in
applying to the paper, previously treated by sulphate of manganese or any other
salt of the same class, a colourless solution the basis of which is a reducing salt
(tin-salt for instance), which prevents the superoxydation of the manganese salt,
and which, under the action of chlorine, calls forth brown stains with white
letters.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is:
First. As a means of preventing the falsification of various commercial and other
documents, such as cheques, bills, bonds, &c. &c., and also ascertaining the genuine-
ness of the same, the Cryptographal' printing of a ground in two or more shades
of the same colour, part of which shades being fugacious or removable, while the
other are fixed and indeliable and represent a denouncing or controlling word,
which becomes and remains visible, upon the fugacious colour or ink being washed
off, substantially as described.
Second. As a means of detecting forgery, the impregnation of the paper with
salt of manganese, of cobalt, or any other similar salt, which, when brought into
contact with an oxidizing decolouring agent or a suitable reagent, causes a par-
ticular colour revealing the attempt at forgery, to become and remain visible,
substantially as described.
Third. The method whereby interested parties or payees may test the genuine-
ness of bills, &c. by means of signs or words placed in determined points, varying
in accordance with certain rules, or an index table, and marked by means of
invisible oil-varnish or gummed inks; the basis of which inks may be either
anhydrous sulphate of copper, (or crystallized sulphate of copper) when they will
become visible under the action of ammonia, sulphuret or prussiate of potash; or
yellow prussiate of potash, when they become visible through the action of copper
or iron salts; which salts also cause invisible inks, the bassis of which is tannin,
to become apparent;-or sulphate of manganese, when they become visible under
the action of chlorine; or phenol or other Phtaleine (but this accessorily), when
they appear under the action of any alkaline solution; or, lastly, salicylate of soda,
or any other salicylate mixed with zinc white or other white, when they become
visible in violet colour under the action of chloride of iron, substantially as
described.
Fourth. As a method of testing bills, etc. and preventing forgery, the impression,
upon paper previously treated by sulphate of manganese or any other salt of the
same kind, by means of a colour, the basis of which is a reducing salt, such as tin
salt, so as to prevent the superoxydation of the salt employed, and make appear on
the paper, through the action of chlorine, brown stains with white characters,
substantially as set forth.