An Improved Photographic Camera for Producing Negatives for use in the Three-colour Printing Process.
Year: 1897

page_text: Date of Application, 19th Mar., 1897
Complete Specification Left, 20th Dec., 1897-Accepted, 26th Feb., 1898
PROVISIONAL SPECIFICATION.
An Improved Photographic Camera for Producing Negatives for use
in the Three-colour Printing Process.
I, JACOB MEYER, Merchant, of 42, Hansa-Ring, Cologne, in the Province of
Rhineland, and Kingdom of Prussia, do hereby declare the nature of this invention
to be as follows:-
As is known in printing in natural colours three or more plates are used, each
of which is sensitized for a special kind of rays. As these plates must be absolutely
similar, there must be three perfectly corresponding negatives of the same object
taken at the same distance and from the same point of view.
As all these operations involve more or less expenditure of time, it is self-evident
that, with the means hitherto at command, it was only lifeless objects of which
several exactly similar negatives could be taken in rapid succession, while portraits
or landscapes with moving objects could either not be produced at all or only with
the greated difficulty.
These drawbacks are now obviated by the new apparatus represented in the
accompanying diagrams, (in Fig. 1 in longitudinal, in Fig. 2 in transverse
section) which permits of the simultaneous production of three or more perfectly
similar negatives by means of an objective, thus rendering possible the production
of portraits and landscapes in natural colours.
The apparatus consists of a photographic camera A with the objective o which
throws a reversed picture of the object to be taken ab upon a screen at a 1-61,
or, as with the terrestrial telescope, in the air.
Three congruent lenses 1, 11, 12 are now placed in the back part of the camera
as close as possible to each other, and in such a manner that the optical axis of each
lense passes through the optical centre of the objective o.
The distance of these lenses 1, 11, 12 from the picture a 1-61 is equal to double
the focal distance of the former. Immediately behind each lense is placed a
right angled isosceles prism p, p 1, p2, the surface of the hypothenuse being coated
with silver (in the illustration only is represented), which deflects the rays
falling through one lense at a right angle, and projects at a 2-62 a new image
of a-b.
Three backs c, c1, c2 (Fig. 2,) each with a sensitized plate, are now placed
at a 2-62.
If the prisms were not used, the images cast by the lenses would partially overlop
each other.
It would indeed, without the use of prisms, be possible, by drawing the lenses
suitably apart, so to place the backs that the images should not overlop. But for
practical reasons the use of prisms is always to be preferred.
The necessary colour-filters are now placed in front of the lenses themselves
or, even against the surfaces of the backs of the prisms.
As sensitized plates for different colours require a different length of exposure,

page_text: each lense has to be provided with a special cover which can be closed as required.
In cases where more than three colour-plates are to be prepared several lenses
can be arranged in the same manner.
The lenses, 11, 12 can also be made to change places with the prisms p, p 1, p2
without altering the effect.
An Improved Photographic Camera for Producing Negatives for use
in the Three-colour Printing Process.
I, JACOB MEYER, Merchant, of 42, Hansa-Ring, Cologne, in the Province of
Rhineland, and Kingdom of Prussia, 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:
As is known in printing in natural colours three or more plates are used, each
of which is sensitized for a special kind of rays. As these plates must be absolutely
similar, there must be three perfectly corresponding negatives of the same object
taken at the same distance and from the same point of view.
As all these operations involve more or less expenditure of time, it is self-evident
that, with the means hitherto at command, it was only lifeless objects of which
several exactly similar negatives could be taken in rapid succession, while portraits
or landscapes with moving objects could either not be produced at all or only with
the greatest difficulty.
These drawbacks are now obviated by the new apparatus represented in the
drawing filed with the Provisional Specification, (in Fig. 1 in longitudinal, in
Fig. 2 in transverse section,) which permits of the simultaneous production of three
or more perfectly similar negatives by means of an objective, thus rendering
possible the production of portraits and landscapes in natural colours.
The apparatus consists of a photographic camera A with the objective o which
throws a reversed picture of the object to be taken a - upon a screen at a¹-b',
or, as with the terrestrial telescope, in the air.
Three congruent lenses 1, 1, are now placed in the back part of the camera
as close as possible to each other, and in such a manner that the optical axis of each
lense passes through the optical centre of the objective o.
The distance of these lenses 1, 1, 2 from the picture is equal to double
the focal distance of the former. Immediately behind each lense is placed a
right angled isosceles prism p, p, p, the surface of the hypothenuse being coated
with silver (in the illustration only p is represented), which deflects the rays
falling through one lense at a right angle, and projects at a² 63 a new image
of a-b.
Three backs c, c¹, (Fig. 2,) each with a sensitized plate, are now placed
at a²²
If the prisms were not used, the images cast by the lenses would partially overlop
each other.
It would indeed, without the use of prisms, be possible, by drawing the lenses
suitably apart, so to place the backs that the images should not overlop. But for
practical reasons the use of prisms is always to be preferred.
or
The necessary colour-filters are now placed in front of the lenses themselves
even against the surfaces of the backs of the prisms.

page_text: As sensitized plates for different colours require a different length of exposure,
each lense has to be provided with a special cover which can be closed as required.
In cases where more than three colour-plates are to be prepared several lenses
can be arranged in the same manner.
The lenses 1, 11, 12 can also be made to change places with the prisms p, p, pa
without altering the effect.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed I declare that what I
claim is:-
:-
1. The process for the simultaneous production of several photographic negatives
whose outlines correspond accurately with each other, thereby characterized that,
in place of the object, an image of it, produced by a system of lenses on a certain
plain is photographed from this plain by the aid of a number (three or more) of
congruent lenses placed next each other substantially as set forth.
2. In the process for the simultaneous production of several photographic
negatives whose outlines correspond accurately with each other, thereby character-
ized that, in place of the object, an image of it, produced by a system of lenses
on a certain plain, is photographed from this plain by the aid of a number (three
or more) of congruent lenses placed next each other, the combination, that in
front of, or at the back of the congruent lenses upon sensitized plates disposed at
the sides, substantially as set forth.
3. The apparatus for the simultaneous production of several photographic nega-
tives whose outlines correspond accurately with each other, consisting in a camera,
provided with an objective o and, parallel with the optical axis of the latter, with
a number of sensitized plates (c, c¹² c² etc.) and between these with a corresponding
number of congruent lenses (1, 11, 12, etc.) each of the latters combined with a
prism (p, p, 12 etc.) so as to deflect at a right angle the rays of the picture from
the axis of the objective on to the plates, substantially as set forth.
Dated this 17th day of December 1897.
For JACOB MEYER,
Bernhard Brockhues.