Manufacture of Photogenic Copying Paper.
Year: 1898

page_text: PROVISIONAL DEV
The Manufacture of Photogenic Copying Paper.
I, CHARLES ZIMMERMANN, of 9 & 10, St. Mary at Hill, in the City of London,
Merchant, do hereby declare the nature of this invention, (which has been com-
municated to me from abroad by The Chemische Fabrik auf Actien vormals E.
Schering, of 170 and 171, Müllerstrasse, Berlin, in the Empire of Germany,)
to be as follows:-
The object of this invention is to produce a positive photogenic copying paper,
which from a drawing in black lines upon a white ground, gives after exposure to
light and development in water, a copy also having black lines upon a white
ground.
Such positive photogenic copying paper is produced by coating in the dark, by
means of a rotating roller or other suitable apparatus, the ordinary so-called ferro-
gallic paper produced according to any of the known methods, either upon the side
sensitive to light, or upon the reverse side, with the solution of a mixture of a
body colouring iron oxide salts, for example gallic acid, tannin, pyrogallol and
the like, and of an organic or inorganic acid in a suitable solvent which does not
dissolve gelatine and rubber, for example alcohol or ether, and thereupon quickly
drying.
of
water
pure
The paper so produced is in the usual manner placed in the light under a drawing
After exposure the paper is washed with a jet
in a copying frame.
or placed in a vessel with a quantity of pure water whereupon the drawing at once
comes out black upon a white ground.
The preparation of the ferro-gallic paper with the solution of a mixture of gallic
acid and the like, and of an acid which does not darken iron oxide salts, has many
advantages. For instance gallic acid alone in alcoholic solution gives to the ferro-
5 gallic paper treated therewith a black voilet discolouration, which renders the
paper unuseable, this is absolutely prevented by the presence of the acid; the iron
salt contained in the ferro-gallic paper remains on the contrary unaltered. Gallic
acid alone, which up to the present has been rubbed upon the paper in a pulverized
form, diminishes its sensitiveness to a considerable extent; by the use of a mixture
30 of bodies colouring iron oxide salts and suitable acids, on the contrary the sensitive-
ness of the paper is not only not prejudicially influenced but rather increased.
Further the development of the copies in water by the use of powdered gallic acid
takes a long time, for the gallic acid is difficultly soluble in water and the blackening
of the iron salt is thereby retarded.
35
Dissolved gallic acid on the contrary operates, on account of its fine division
almost immediately, so that the development of a photogenic copy only takes
short time.
The presence of the organic or inorganic acids has also a purifying action upo
the white ground of the paper so that photogenic copies are obtained of muc

page_text: To make positive photogenic copying paper producing violet lines upon a white
ground the following may be used.
Ordinary positive photogenic copying paper, the so called ferro-gallic paper is
coated with a solution of
Gallic acid 150 to 200 grams.
Tartaric acid 50 to 80 grams.
In alcohol 1000 cubic centimetres.
Instead of gallic acid any other salt in suitable quantities rendering iron oxide
salt dark for example pyrogallol, tannin and the like may be used; instead of
tartaric acid citric acid, oxalic acid, anhydrous acetic acid, alcoholic hydrochloric
acid or other acid not darkening iron oxide salts may be used; instead of alcohol
any other solvent capable of dissolving the before mentioned substances and acids
in sufficient quantities, which however leave the substances contained in the ferro-
gallic paper unaltered as for example ether, amylalcohol, acetone, methylalcohol and
the like may be used.
By a suitable choice of the bodies which colour iron oxide salts different shades
of black as also other colours may be obtained.
Dated this 31st day of March 1898.
I, CHARLES ZIMMERMANN, of 9 & 10, St. Mary at Hill, in the City of London,
Merchant, do hereby declare the nature of this invention, (which has been com-
municated to me from abroad by The Chemische Fabrik auf Actien vormals E.
Schering, of 170 and 171, Müllerstrasse, Berlin, in the Empire of Germany,)
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 this invention is to produce a positive photogenic copying paper,
which from a drawing in black lines upon a white ground, gives after exposure to
light and development in water, a copy also having black lines upon a white
ground.
Such positive photogenic copying paper is produced by coating in the dark, by
means of a rotating roller or other suitable apparatus, the ordinary so-called ferro-
gallic paper (which is a paper containing ferric chloride and tartaric acid and is
usually developed by gallic acid) produced according to any of the known methods,
either upon the side sensitive to light, or upon the reverse side, with the solution of
a mixture of a body colouring iron oxide salts, for example gallic acid, tannin,
pyrogallol and the like, and of an acid which prevents the premature formation of
a dyestuff between the developer (gallic acid) and the light sensitive salt (ferric
salt) and does not itself darken the ferric salt in a suitable solvent which does not
dissolve gelatine and rubber, for example alcohol or ether, and thereupon quickly
drying.
The paper so produced is in the usual manner placed in the light under a drawing
in a copying frame. After exposure the paper is washed with a jet of pure water
or placed in a vessel with a quantity of pure water whereupon the drawing at once
comes out black upon a white ground.
The preparation of the ferro-gallic paper with the solution of a mixture of
gallic acid and the like, and of an acid which prevents the premature
formation of a dyestuff between the developer (gallic acid) and the

page_text: not
ight sensitive salt (ferric salt) and does not itself darken the ferric
darken iron oxide salts, has many advantages.
alt which does
For instance gallic acid alone in alcoholic solution gives to the ferro-gallic paper
reated therewith a black violet discolouration, which renders the paper unuseable,
his is absolutely prevented by the presence of the acid; the iron salt contained in
the ferro-gallic paper remains on the contrary unaltered. Gallic acid alone, which
up to the present has been rubbed upon the paper in a pulverized form, diminishes
its sensitiveness to a considerable extent, by the use of a mixture of bodies
darkening iron oxide salts and suitable acids, on the contrary the sensitiveness of
the paper is not only not prejudicially influenced but rather increased. Further the
development of the copies in water by the use of powdered gallic acid takes a long
time, for the gallic acid is difficultly soluble in water and the blackening of the
iron salt is thereby retarded.
Dissolved gallic acid on the contrary operates, on account of its fine division,
almost immediately, so that the development of a photogenic copy only takes a
short time.
The presence of such an acid has also a purifying action upon the white ground
of the paper so that photogenic copies are obtained of much purer white.
To make positive photogenic copying paper producing violet lines upon a white
ground the following may be used.
Ordinary positive photogenic copying paper, the so called ferro-gallic paper is
coated with a solution of
Gallic acid 150 to 200 grams.
Tartaric acid 50 to 80 grams.
In alcohol 1000 cubic centimetres.
Instead of gallic acid any other salt in suitable quantities rendering iron oxide
salt dark for example pyrogallol, tannin and the like may be used; instead of
tartaric acid citric acid, oxalic acid, anhydrous acetic acid, alcoholic hydrochloric
acid or other acid not darkening iron oxide salts may be used; instead of alcohol
any other solvent capable of dissolving the before mentioned substances and acids
in sufficient quantities, which however leave the substances contained in the ferro-
gallic paper unaltered as for example ether, amylalcohol, acetone, methylalcohol
and the like may be used.
By a suitable choice of the bodies which colour iron oxide salts different shades
of black as also other colours may be obtained.
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 manufacture of photogenic copying paper developable in water, by treat-
Ding ordinary so called ferro-gallic copying paper with a solution of a mixture of a
body darkening the iron salts and of an acid not darkening the iron salts and which
prevents the premature formation of a dyestuff between the developer and the light
sensitive salt, substantially as described.
2. The manufacture of photogenic copying paper by treating ordinary so called
5 ferro-gallic copying paper with a solution of gallic and tartaric acids.
3. The photogenic copying paper substantially as described.
T
11808
C. ZIMMERMANN.