Year: 1899

page_text: I, HANS LOESCHER, of Victoriastrasse 54, Lankwitz, near Berlin, Germany,
Photographer, do hereby declare the nature of this invention to be as follows:
Photographic printing machines for printing photographs from negatives by
means of artificial light and whose use shortens the time required for printing
photographs are known.
Some of these exposure printing machines work with flat and others with
curved or cylindrical negatives.
The first mentioned have principally the disadvantage that their mechanism
is naturally very complicated working intermittently but not continuously and
their action is not always sure. The others with cylindrical or curved negatives
have no means for preventing the loosening or displacement of the films which
often takes place. Both systems have the disadvantage that by their use only
indifferent positives could be obtained as the sensitive paper or film was not
constantly and absolutely flat against the negative.
The knowledge of these disadvantages led to the construction of exposure
printing machines with transparent negative cylinders containing the light.
source and rotating continuously.
In these machines celluloid films are used as negatives being laid over the
surfaces of the rotating transparent cylinders and against which the sensitive
paper is pressed; this is done in one system by means for fastening the print-
ing paper and in the other by a pressure band or fabric passing round the
cylinder.
Although these two systems show an undeniable progress in comparison with
the older exposure printing machines, they do not answer the requirements for
producing good and distinct copies or prints for the following reasons:
The arrangement of the negative films on the glass cylinder has manifold
disadvantages as the films never lie absolutely flat on the cylinder, some smaller
or larger cockles being invariably produced which when the positive paper is
pressed against the negatives are generally squeezed together into creases or in
any case prevent a sharp copy being obtained; also when the films are loosened
from the cylinders there is always the danger that the negative or part of the
positive paper is ruined.
For producing distinct copies the stretching pressure of the copying paper is
not sufficient; the same is scarcely greater than possibly the pressure of a simple
negative plate on the paper and the smallest air blister between paper and nega-
tive is sufficient to prevent the production of a distinct copy; further the copy-
ing paper turns the negative cylinder by its forward movement so that slipping
of the paper on the cylinder can not be prevented which is a further detriment
to the production of good copies.

page_text: If on the other hand the copying paper is pressed against the cylinder by a
fabric passing round the same, displacements and creases of the films cannot
be observed during the process and can only be discovered when the whole series
has been printed.
The object of the present invention is a photographie printing machine having
a rotary transparent negative cylinder in which the mentioned disadvantages
are avoided.
In this machine the negative is secured in the following manner on the rotary
cylinder.
First a flat negative is produced the plate having a sensitised layer of film
which can easily be separated from its base or support, such films for instance
consist of sensitised collodion or bichromated gelatine which are put on glass,
paper and the like supports. After a good negative has been obtained the film
is separated from its base and transferred to the transparent cylinder, which can
be done in manifold ways. By means of a suitable adhesive substance the film
can thus be fixed as closely and securely to the cylinder as on a flat glass plate.
The following method is very suitable:
First an ordinary negative is produced which is retouched and equalized as
usual. From this technically perfect negative a diapositive is made in the
known manner. The so obtained diapositive serves then as a negative for the
production of a copy on pigmented and bichromated gelatine paper. Of course
this copy can also be made on a sensitive collodion or celloidin laver, the kind of
base for the sensitive layer being indifferent as long as the developed layer
can be easily separated and transferred to another base. From a technical point
of view the so-produced negative cylinder does not differ from a flat negative of
the ordinary kind and from such a negative cylinder equally distinct copies
can be obtained as from such flat negative supposing it is suitably exposed
before a constantly moving sensitive material. As the negative film is attached
in the same manner on the cylinder as on a flat plate, it adheres equally tightly
on to the same, and cockling or creasing is out of the question.
The printing paper is pressed on to the negative cylinder in this machine by
a second cylinder provided with an elastic mantle forming its operative sur-
face this cylinder being moved either by the negative cylinder by friction or,
when driven itself, moves the negative cylinder by friction. A form of con-
struction of the improved printing machine may be as follows:
The transparent negative cylinder is mounted suitably on an axle, the light
source being arranged inside this cylinder and consisting for instance of an
incandescent electric lamp or lamps which can project its light rays only in
certain directions. This is obtained by suitable screens arranged in the cylin-
der. By this arrangement it is possible to observe the negative during print-
ing which was not possible with any of the hitherto known machines. Opposite
the negative cylinder a pressure cylinder is arranged the operative surface of
which is formed by an elastic air cushion. The two cylinders can be suitably
brought in proximity with one another and by inflating the air cushions a rela-
tively large meeting area between the two cylinders is produced and further
the rotary movement of the one is transferred to the other without fear of sliding
or slipping.
If for instance the negative cylinder is put in motion the pressure cylinder
is bound to rotate also and a possibly endless band of sensitised paper brought
between the two, is drawn with them without slipping. It is evident that the
negative will give exceedingly distinct positive copies on the sensitised paper
as all parts of the paper are equally pressed against the negative which, as
mentioned already cannot be obtained in previous machines. Moreover as the
paper is continually moved on. the working with this machine is much quicker
than hitherto. With this machine prints can be produced which do not techni-
cally differ from photographic prints produced in the usual manner. The effect
of the machine can be augmented by arranging several sensitised paper strips

page_text: which are pressed against the cylinder suitably provided with negatives by
means of several pressure cylinders.
Dated this 5th day of October 1899.
HERBERT HADDAN & Co.,
Agents to Applicant.
improvements in Photographic Frinting Machines.
I, HANS LOESCHER, of No. 54, Victoriastrasse, Lankwitz, near Berlin, Ger-
many, Photographer, do hereby declare the nature of my said invention and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
Photographic printing machines for printing photographs from negatives by
means of artificial light and whose use shortens the time required for printing
photographs are known.
Some of these exposure printing machines work with flat and others with
curved or cylindrical negatives.
The first mentioned have principally the disadvantage that their mechanism
is naturally very complicated working intermittently but not continuously and
their action is not always sure. The others with cylindrical or curved negatives
have no means for preventing the loosening or displacement of the films which
often takes place. Both systems have the disadvantage that by their use in-
different positives could be obtained as the sensitive paper or film
constantly and absolutely flat against the negative.
was not
The knowledge of these disadvantages led to the construction of exposure
printing machines with transparent negative cylinders containing the light
source and rotating continuously.
In these machines celluloid films are used as negatives being laid over the
surfaces of the rotating transparent cylinders and against which the sensitive
paper is pressed: this is done in one system by means for fastening the print-
ing paper and in the other by a pressure band or fabric passing round the
cylinder.
Although these two systems show an undeniable progress in comparison with
the older exposure printing machines they do not answer the requirements for
producing good and distinct copies or prints for the following reasons:
The arrangement of the negative films on the glass cylinder has manifold
disadvantages as the films never lie absolutely flat on the cylinder, some smaller
or larger cockles being invariably produced which when the positive paper is
pressed against the negatives are generally squeezed together into creases or in
any case prevent a sharp copy being obtained; also when the films are loosened
from the cylinders there is always the danger that the negative or part of the
positive paper is ruined.
For producing distinct copies the tension pressure of the copying paper is
not sufficient the same is scarcely greater than possibly the pressure of a simple
negative plate on the paper and the smallest air blister between paper and nega-
tive is sufficient to prevent the production of a distinct copy; further the copy-
ing paper turns the negative cylinder by its forward movement so that slipping
of the paper on the cylinder can not be prevented, which is a further detriment
to the production of good copies.
If on the other hand the copying paper is pressed against the cylinder by a
fabric passing round the same, displacements and creases of the films cannot

page_text: be observed during the process and can only be discovered when the whole series
has been printed.
The object of the present invention is a photographic printing machine having
a rotary transparent negative cylinder in which the mentioned disadvantages
are avoided.
In this machine the negative is secured in the following manner on the rotary
cylinder.
The accompanying drawing shows by way of example a diagrammatic sec-
tional view of such negative cylinder.
The negative cylinder consists of the rigid transparent cylinder a of glass
or the like with the negative film b. The latter is a film which is produced
in the known manner on a flat glass and can be separated from the same; such
films are, for instance, the sensitised collodion or bichromated gelatine film or
layer on glass, paper or any other base. The separation of the film from the
flat plate for being transferred to the transparent cylinder a takes place after
the production of a copying negative and the securing on to the cylinder a in
the usual manner, for instance, by using a suitable adhesive substance, by means
of which, the film can be fixed as closely and securely to the cylinder as on a
flat glass plate.
The following method is very suitable;
First an ordinary negative is produced, which is retouched and equalized as
usual. From this technically perfect negative a diapositive is made in the
known manner. The so obtained diapositive serves then as a negative for the
production of a copy on pigmented and bichromated gelatine paper. Of course.
this copy can also be made on a sensitive collodion or celloidin laver, the kind of
base for the sensitive layer being indifferent as long as the developed layer
can be easily separated and transferred to another base. From a technical point
of view the so-produced negative cylinder does not differ from a flat negative of
the ordinary kind and from such a negative cylinder equally distinct copies
can be obtained as from such flat negative supposing it is suitably exposed
before a constantly moving sensitive material. As the negative film is attached
in the same manner on the cylinder as on a flat plate, it adheres equally tightly
on to the same, and cockling or creasing is out of the question.
The printing paper is pressed on to the negative cylinder in this machine
by a second cylinder d provided with an elastic mantle forming its operative
surface, this cylinder being moved either by the negative cylinder by friction
or, when driven itself, moves the negative cylinder by friction. A form of con-
struction of the improved printing machine may be as follows:
The transparent negative cylinder is mounted suitably on an axle, the light
source being arranged inside this cylinder and consisting, for instance, of an
incandescent electric lamp or lamps, which can project its light rays only in
certain directions. This is obtained by suitable screens arranged in the cylin-
der. By this arrangement it is possible to observe the negative during print-
ing, which was not possible with any of the hitherto known machines. Opposite
the negative cylinder a pressure cylinder is arranged the operative surface of
which is formed by an elastic air cushion. The two cylinders can be suitably
brought in proximity with one another and by inflating the air cushions a rela-
tively large meeting area between the two cylinders is produced and further
rotary movement of the one is transferred to the other without fear of sliding
or slipping.
If, for instance, the negative cylinder is put in motion the pressure cylinder
is bound to rotate also and a possibly endless band of sensitised paper brought
between the two, is drawn with them without slipping. It is evident that the
negative will give exceedingly distinct positive copies on the sensitised paper
as all parts of the paper are equally pressed against the negative which, as
Moreover as the
mentioned already cannot be obtained in previous machines.
paper is continually moved on, the working with this machine is much quicker

page_text: than hitherto. With this machine prints can be produced, which do not techni-
cally differ from photographic prints produced in the usual manner.
The effect
of the machine can be augmented by arranging several sensitised paper strips,
which are pressed against the cylinder suitably provided with negatives by
means of several pressure cylinders.
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/. In photographic printing machines the improved process of making nega-
tives, characterized by the fact that the developed negative film of a flat collo-
dion negative is separated from the latter and secured to the cylinder mantle
substantially as described and for the purpose set forth.
2/. In photographic printing machines the improved process of making nega-
tives characterized by the fact that the developed negative film of a flat gelatine
negative is separated from the latter and secured to the cylinder mantle, sub-
stantially as described and for the purpose set forth.
3/. In photographic printing machines, the improved process of making nega-
tives, characterized by the fact, that from an ordinary negative, a diapositive
is first made and this is then copied on any suitable material, paper or the like
coated with sensitive collodion whereupon the layer or film of collodion is then
separated from the paper or the like and transferred to the cylinder mantle, sub-
stantially as described and for the purpose set forth.
4/. In photographic printing machines, the improved process of making nega-
tives characterized by the fact, that from an ordinary negative, a diapositive
is first made and this is then copied on any suitable material, paper or the like
coated with sensitive albumin, whereupon the layer or film of albumin is then
separated from the paper or the like and transferred to the cylinder mantle,
substantially as described and for the purpose set forth.
5/. In photographic printing machines, the improved process of making nega-
tives, characterized by the fact, that from an ordinary negative, a diapositive is
first made and this is then copied on any suitable material, paper or the like
coated with sensitive gelatine, whereupon the layer or film of gelatine is then
separated from the paper or the like and transferred to the cylinder mantle,
substantially as described and for the purpose set forth.
6/. In photographic printing machines, the improved process of making nega-
tives, characterized by the fact, that from an ordinary negative, a diapositive is
first made and this is then copied on any suitable material, paper or the like
coated with sensitive glue, whereupon the layer or film of glue is then separated
from the paper or the like and transferred to the cylinder mantle, substantially
as described and for the purpose set forth.
T 1.1. Jav af Tune 1000
ALLISON BROS.,
Agents for the Applicant.