AN IMPROVED MANUFACTURE OF SAFETY PAPER FOR CHEQUES AND SIMILAR PURPOSES to be as follows:
Year: 1885

page_text: .
PROVISIONAL SPECIFICATION.
T
I, CHARLES DENTON ABEL, of No 28 Southampton Buildings Chancery Lane in
the county of Middlesex, Consulting Engineer and Patent Agent, do hereby declare
the nature of my invention for "AN IMPROVED MANUFACTURE OF SAFETY PAPER
FOR CHEQUES AND SIMILAR PURPOSES to be as follows:-
"1
This invention relates to the manufacture of paper that shall at once indicate
any alteration effected by chemical means of writing or other marks made thereon.
The known methods for the production of such safety paper either do not offer
perfect security for the purpose required, on account of the chemical reagents
employed therein, or they are of such a complicated nature as not to be practically
available.
According to the present invention the purpose aimed at is attained by manu-
facturing a colored paper of such a nature that the chemicals employed for removing
writing or other marks in ink from the same, such as acids, chlorine &c, will destroy
or alter the color, the paper thus affording the required safety, as any attempt to
remove or alter the writing will at once become visible thereon.
The requisite operations for the preparation of such paper are at the same time
very simple and do not affect or complicate the ordinary process of manufacturing
paper, as the requisite chemicals need only be added to the paper material in the
rag engine.
The invention is carried out in practice as follows:
The paper material is colored with indigo, preferably with indigo from the
steeping trough and is mixed with a chromate that is insoluble in water and soluble
in acids (such as chromate of barium). The extent to which the latter is added
depends upon the degree of blue green to yellow green coloration of the paper
desired.
,

page_text: On paper so prepared dilute mineral acids effect a separation of chromic acid that
destroys the indigo blue; chlorine and solution of chloride of lime also destroy the
indigo blue and cause a yellow color to appear.
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.
•
I, CHARLES DENTON ABEL, of N° 28 Southampton Buildings, Chancery Lane in
the County of Middlesex Consulting Engineer and Patent Agent do hereby declare
the nature of my invention for "AN IMPROVED MANUFACTURE OF SAFETY PAPER
FOR CHEQUES AND SIMILAR PURPOSES and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:
"
This invention relates to the manufacture of paper that shall at once indicato
any alteration, effected by chemical means, of writing or other marks made thereon.
The known methods for the production of such safety paper, either do not offer
perfect security for the purpose required, on account of the chemical reagents
employed therein, or they are of such a complicated nature as not to be practically
available.
According to the present invention, the purpose aimed at is attained by manu-
facturing a colored paper of such a nature that the chemicals employed for removing
writing or other marks in ink from the same, such as acids, chlorine &c, will destroy
or alter the color, the paper thus affording the required safety, as any attempt to
remove or alter the writing will at once become visible thereon.
The requisite operations for the preparation of such paper are at the same time
very simple and do not affect or complicate the ordinary process of manufacturing
paper, as the requisite chemicals need only be added to the paper material in the
rag engine. The invention is carried out in practice as follows:
The paper material is colored with indigo, preferably with indigo from the
steeping trough, and is mixed with a chromate that is insoluble in water and soluble
in acids (such as chromate of barium). The extent to which the latter is added
depends upon the degree of blue-green to yellow-green coloration of the paper
desired,

page_text: On paper so prepared dilute mineral acids effect a separation of chromic acid that
destroys the indigo blue; chlorine and solution of chloride of lime also destroy the
indigo blue and cause a yellow color to appear.
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
1, The process of producing safety paper wherein the paper material after being
colored with indigo, is treated with chromates insoluble in water but soluble in
acids.
2, An improved manufacture of safety paper prepared as herein set forth
whereby it has a blue-green to yellow-green colour imparted to it of such a nature
as to be destroyed or altered on treatment with chlorine acids or alkalis.
Dated this 23rd day of June 1885.
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.