Improvements in Surfaces for Transferred Lithographic Printing, and for Photographic Printing, and Process for the Production thereof.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in Surfaces for Transferred Lithographic Printing,
and for Photographic Printing, and Process for the Production
thereof.
I, ARTUR DUFFEK, of 1 Elisabethstrasse No. 22 Vienna, Austria, Engineer,
do hereby declare the nature of this invention to be as follows:-
Surfaces for transferred printing for lithographic purposes, which are stored
in lieu of the heavy and expensive lithographic stones, for any subsequent re-
prints that may be required, and which can be used in the same way as the stones,
have heretofore been prepared by hardening gelatine plates by the action of alum
or earth-alkali salts, and rendering them impervious to water.
This process is also employed for the preparation of so called stone paper, in
which the gelatine has added to it some glycerine and zinc white, or in lieu of
the latter white lead, the mixture being used as a pigment which is applied to
paper and is then hardened by means of alum.
This stone paper is however subject, notwithstanding the advantages resulting
from its use for lithographic purposes, to numerous disadvantages and shews
objectionable properties which cause considerable difficulties when effecting the
transferred printing.
Experience has shewn that these disadvantages are caused by the properties
of the body colours (zinc white, white lead) used in the preparation of the stone
paper; they have the effect that the stone paper requires to be dried for months
before it can be employed with advantage; this is in particular the case with
Such
grained paper as the grain can only be produced with great difficulty.
grained papers must be stored for a long time before they can be used, as the
coating of pigment is very hygroscopic, and consequently, in the case of imperfect
drying, the entire drawing will be rubbed away or disappear when in use.
Even in the application of grained stone paper for photographic purposes, very
considerable difficulties arise.
The engraving process is hardly applicable at all on this stone paper and it is
also found that in scratching out or re-application of drawings on stone paper
the drawings become spoilt and useless.
The coating is too soft, as experience has shown that alum alone does not afford a
sufficient hardening of the gelatine, and consequently the applied coating gives
way under continued rubbing. This disadvantage arises more particularly, when
it is required to take fresh impressions from such transferred printing surfaces
or cliches after they have been kept for a long time.
All the above disadvantages are obviated by means of the improved manufac-
ture of surfaces for transferred printing according to the present invention.
The process consists on the one hand, in substituting cement for the body
colours (zinc white, white lead) which as above stated are the cause of many
defects in the stone paper or in the case of surfaces for transferred printing for

page_text: photographic purposes, in replacing the said substances by barium carbonate as
an addition to the gelatine.
On the other hand the process consists in effecting the hardening by means of
a mixture of alum and formaldehyde instead of by alum alone.
The cement found to be most useful for the above purpose is carrara cement,
which, in consequence of the very finely grained structure of carrara marble
possesses the advantage that already by the application of a layer thereof as pig-
ment, a fine natural grain can be produced on the surface, which in most cases
renders a special graining of the paper unnecessary, while for the purpose of
obtaining a still finer grain it is only necessary to place two sheets provided
with the said coating with their coated surfaces upon each other and then passing
them through a roller satin press.
The applied coating hardens in a very short time so as to form a stone-like
mass; the surfaces for transferred printing do not therefore require to be stored
a long time to be dried, and after the application of the coating it can easily be
grained, a much deeper grain being attainable than with the existing manufac-
ture and one that cannot be easily defaced.
For the surfaces for transferred printing to be used in photography it is of
advantage to replace the cement by barium carbonate for mixing with the gela-
tine, because such a coating can be more readily treated in the silver or gold bath.
In manufacturing the compound for the coating, the carrara cement or barium
carbonate should be added to a concentrated aqueous solution of gum or gelatine.
Also Cologne glue can be used with goou effect in place of these substances.
As foundation for the said coating there may be used, in place of paper, sheet
metal, leather thin wooden plates, and the like.
Dated this 4th day of December 1899.
ABEL & IMRAY,
Agents for the Applicant.
Improvements in Surfaces for Transferred Lithographic Printing
and for Photographic Printing, and Process for the Production
thereof.
I, ARTUR DUFFEK, of 1 Elisabethstrasse No. 22 Vienna, Austria, Engineer,
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
following statement:-
the
Surfaces for transferred printing for lithographic purposes, which are stored in
lieu of the heavy and expensive lithographic stones, for any subsequent reprints
that may be required, and which can be used in the same way as the stones, have
heretofore been prepared by hardening gelatine plates by the action of alum or
earth alkali salts, and rendering them impervious to water. Surfaces for photo-
graphic printing have been prepared in a similar manner.
This process is also employed for the preparation of so-called stone paper, in
which the gelatine has added to it some glycerine and zinc white, or in lieu of the
latter white lead, the mixture being used as a pigment which is applied to paper
and is then hardened by means of alum. .
This stone paper is however subject, notwithstanding the advantages resulting
from its use for lithographic purposes, to numerous disadvantages and shews objec-
tionable properties. which cause considerable difficulties when effecting the trans-
ferred printing.

page_text: Experience has shewn that these disadvantages are caused by the properties of
the body colours (zine white, white lead) used in the preparation of the stone
paper; they have the effect that the stone paper requires to be dried for months
before it can be employed with advantage; this is in particular the case with
grained paper as the grain can only be produced with great difficulty. Such
grained papers must be stored for a long time before they can be used, as the
coating of pigment is very hygroscopic and consequently, in the case of imperfect
drying, the entire drawing will be rubbed away or disappear when in use.
Even in the application of grained stone paper for photographic purposes, very
considerable difficulties arise.
The engraving process is hardly applicable at all on this stone paper and it is
also found that in scratching out or re-application of drawings on stone paper the
drawings become spoilt and useless.
The coating is too soft, as experience has shewn that alum alone does not afford
a sufficient hardening of the gelatine, and consequently the applied coating gives
way under continued rubbing. This disadvantage arises more particularly when
it is required to take fresh impressions from such transferred printing surfaces
or cliches after they have been kept for a long time.
All the above disadvantages are obviated by means of the improved manufac-
ture of surfaces for transferred printing according to the present invention.
The process consists on the one hand, in substituting cement for the body
colours (zinc white, white lead) which as above stated are the cause of many
defects in the stone paper or, in the case of surfaces for photographic printing,
in replacing the said substances by barium carbonate as an addition to the
gelatine.
On the other hand the process consists in effecting the hardening by means
of a mixture of alum and formaldehyde instead of by alum alone.
The cement found to be most useful for the above purpose is carrara cement,
which, in consequence of the very finely grained structure of carrara marble
possesses the advantage that already by the application of a layer thereof as pig-
ment, a fine natural grain can be produced on the surface, which in most cases
renders a special graining of the paper unnecessary, while for the purpose of
obtaining a still finer grain it is only necessary to place two sheets provided with
the said coating with their coated surfaces upon each other and then passing
them through a roller satin press.
The applied coating hardens in a very short time so as to form a stone-like
mass; the surfaces for transferred printing do not therefore require to be stored
a long time to be dried, and after the application of the coating it can easily be
grained, a much deeper grain being attainable than with the existing manu-
factures and one that cannot be easily defaced.
For the surfaces for photographic printing it is of advantage to replace the
cement by barium carbonate for mixing with the gelatine, because such a coating
can be more readily treated in the sensitising or toning bath.
In manufacturing the compound for the coating, the carrara cement or barium
carbonate should be added to an aqueous solution of gum or gelatine, preferably
of about 10 per cent. strength until there is obtained a thick mixture which is
still easily applied by means of a brush. Also Cologne glue can be used with
good effect in place of these substances.
As foundation for the said coating there may be used in place of paper, sheet
metal, leather, thin wooden plates, and the like.
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. Process for the production of surfaces for transferred lithographic printing
and for photographic printing, consisting in preparing a mixture of a concen-
trated aqueous solution of gelatine, gum, or Cologne glue with cement or barium

page_text: carbonate to form a paste, which is then spread in a thin layer upon a backing
of paper, metal, leather, or wood, such layer being then hardened by means of a
mixture of alum solution and formaldehyde, substantially as described.
2. Surfaces for transferred lithographic printing and for photographic printing
consisting of a backing of paper, metal, leather, or wood on which is spread a
layer composed of a mixture of either gelatine, gum or Cologne glue with cement
of barium carbonate such layer being rendered hard and insoluble by treatment
with alum solution and formaldehyde, substantially as described.
Dated this 6th day of March 1900.
ABEL & IMRAY,
Agents for the Applicant.