Improvements in Apparatus for Exhibiting Photographs in Natural Colours.
Year: 1899

page_text: Date of Application, 17th Oct., 1899-Accepted, 2nd Dec., 1899
COMPLETE
SPECIFICATION.
Improvements in Apparatus for Exhibiting Photographs in Natural
Colours.
I, ROBERT KRAYN, of 58, Oranienburgerstrasse, Berlin, Germany, Civil Engineer
and Patent Agent, 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:.
The apparatus hitherto known for exhibiting photographs in natural colours,
for example, the Ives and Zink chromoscopes are all arranged in such a manner
that a person looking into the apparatus sees only the finished picture.
For this reason, in case it be desired to make coloured photographs accessible
to the general public, in automatic apparatus, deception might easily arise, as
the spectator, when only the finished picture is presented to his view, has no means
of determining whether such is really a photograph in natural colours, or an
ordinary painted photograph.
The object of this invention is to bring the development of the coloured picture
before the eyes of the spectator, in such a way that the latter sees at first what
appears as an ordinary photograph and not one that is effected by a colouring
light filter, and thereafter part-pictures, appearing in the three ground colours,
are successively brought to view, and the complete picture then appears in natural
colours.
This purpose is attained by the arrangement of moveable mirrors and con-
tingently also of moveable screens in front of separate part-pictures.
The operations of this invention is as follows:-
In the position of rest, the two mirrors, which are employed for bringing to
view two of the part-pictures into the optical axis of the ocular, are outside the
range of view of the eye and only the one part-picture is visible, that which lies
directly in the optical axis of the ocular, and which, like the two others, is a
glass diapositive in black and white and is lighted by a white reflector behind.
By means of a crank or clock-work, the disengaging of which can be effected by
the insertion of a coin in any preferred manner the mirrors are gradually carried
into the interior of the apparatus and within the optic range of the eye, and at
length attain by means of a suitable mechanical arrangement, the position in
which the other two picture-parts, made visible by means of the mirrors, come
into the optical axis of the ocular, and are covered at all points by the directly
visible picture.
For automatic purposes, the mechanism can be arranged in such a manner that
the mirrors, after a certain time, return to the position of rest.
With the mechanism for moving the mirrors, the screens which are intended
to cover the two diapositive part-pictures before the moving of the mirrors into
the position for use, can be so connected that they release the two diapositives
successively. The white reflector also, which illuminates the directly visible
picture-part, can be so moved aside when the mirrors are moved, that the picture-
part directly visible becomes illuminated by a yellow reflector placed below.
The moveable screens, as also the white reflector, are, however, not absolutely
necessary for the intended purpose, as without them the production or origination
of the coloured picture will be clearly shown.
The directly visible picture is in this case illuminated by a yellow reflector
and appears in ordinary photographic tones on a bright yellow background, whilst
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page_text: in the mirrors, which in consequence of their position in relation to their axis of
rotation, appear successively within the range of vision of the spectator's eye, the
red and blue part-pictures become successively visible.
The accompanying drawings represent such an Ives chromoscope with this
invention applied thereto.
Fig. 1 shows the apparatus in partially vertical section, the mirrors being in the
position of rest.
Fig. 2 is an elevation from the left of Fig. 1.
Fig. 3 shows the apparatus likewise in partially vertical section with the mirrors
in the working position, whilst
Fig. 4 is an elevation from the left of Fig. 3.
In the chromoscope, a and b are the two moveable mirrors above mentioned.
These are supported by the plate c and move together with the latter around the
axis d. The motion itself is produced by means of a came on the circumference
of which a small roller f, supported by a bracket y fixed to the plate e, slides.
On the shaft e¹ of the cam e a tooth-wheel e² for rotating the shaft el may be
provided as shown in Figs. 2 and 4, the rotation may also be effected directly by
hand, through the medium of a crank keyed on the shaft e¹.
The cam is so constructed that when it makes a quarter turn, the mirrors are
moved out of the position of rest into the working position, then, upon the
execution of a further half-turn the mirrors are left in the working position and
therefore, at the last quarter-turn, the mirrors are returned again to the position
of rest.
In the position of rest for the mirrors, the small roller f is in the heart-shape
incision of the cam e as shown in Fig. 1. Upon the cam being rotated, no matter
in which direction, the roller is brought out of the heart shape incision to the
concentric circumference of the cam. As soon as this is effected the mirrors take
the working position indicated in Fig. 3 in which the three part-pictures are
superposed. The mirrors remain in their working position until the roller f
leaves the concentric circumference of the cam, whereupon the mirrors move back
again until the roller in the heart shaped incision of the cam forms their immove-
able point of support.
Instead of the cam e any other suitable means may as a matter of course be
employed, which will produce the same movement of the mirrors.
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 chromoscopes of any kind the arrangement of moveable inside mirrors.
in such a manner that in their position of rest only the directly visible part-
picture appears, whilst, when the mirrors are placed in the working position, the
two other picture-parts also appear, and the picture is seen in the natural colours;
the directly visible part-picture may be so illuminated that it appears in black
and white when the mirrors are in the position of rest but assumes the third
ground or primary colour, when the mirrors are in the working position.
(2) A modification of the chromoscope indicated in Claim 1, in which the two-
part-pictures not directly visible, or, in other words, the colouring light filter
employed for illuminating the same are covered by screens in such a manner that
these two part-pictures are only successively released after the inside mirrors
are placed in the working position, for the purpose of showing the blending of
the three colour phases whence the picture in the natural colours is produced.
1711 Ja of Ontabar 1800
F. W. GOLBY,
Patent Agent, 36, Chancery Lane, London, W.C., Agent for the Applicant."