Improvements in Colour Photographs, and Apparatus for Producing and Viewing the same.
Year: 1895

page_text: Date of Application, a rep
Complete Specification Left, 19th Dec., 1895-Accepted, 15th Feb., 1896
TRYIDIONAL
DIECIFICATION.
Improvements in Colour Photographs, and Apparatus for Producing
and Viewing the same.
I, BENJAMIN JOSEPH EDWARDS, of The Grove, Hackney, in the County of
Middlesex. Manufacturer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to improvements in colour photographs or photographic
pictures by means of which objects are represented in their natural colours and to
improvements in apparatus and appliances for producing and viewing such colour
photographs.
By my invention I facilitate the production and viewing of such colour
photographs, and I produce the desired results by simpler means than have been
heretofore used.
In carrying out my invention, I use (what is known as the three colour system
of photography) and make three negatives on colour sensitive plates each negative
being made to represent one of the three primary colour sensations. Thus the
negative to represent the red sensation is taken through a colour screen or light
filter which cuts off all or the greater portion of those rays of light which do not
form part of that sensation; the same is also done in making the negative to
represent the green sensation; and also in the case of the blue violet sensation.
I use for the negative of the red sensation, a colour screen of orange tint, in
conjunction with a plate sensitive to red and orange rays. For the negative to
represent the green sensation I use a colour screen which cuts off nearly all the
blue and violet rays, in combination with a plate which is sensitive to the green,
yellow and orange rays; and for the negative of the blue or violet sensation I use
an ordinary plate which is particularly sensitive to those rays either with or
without a screen to cut off the yellow rays. In this way I obtain three photo-
graphic negatives, each of which represents one of the three fundamental colour
sensations by means of which we are able to perceive all the colours in nature.
One way of viewing the representation of the object photographed so as to see
the natural colours of the original is to make transparent positives from the three
negatives, and view each positive through a screen which represents its own
primary colour sensation. When the three colour illuminated positives are
combined or superimposed by optical means so that they are coincident, the
coloured lights and shades blend, and the eye sees one image in all the original
colours of the object. Printing blocks may be made from the three negatives, and
printed in their corresponding or complementary colours; the three impressions
being superimposed give the various tints required to produce the complete coloured
picture.
According to the methods heretofore employed, the three negatives are taken on
separate plates by separate consecutive exposures, or three separate negatives are
obtained on one plate by a single exposure. By my improved method I take the
three negatives on three separate plates at one and the same time by a single
exposure. In this way I am able easily to produce colour photographs of many
subjects which could not be easily photographed in colours by other methods. In
carrying out this part of my invention I construct a special camera furnished with
a lens or objective of the ordinary kind. This camera is constructed to carry three

page_text: separate plates each of which receives an image formed by the rays of light passing
through the lens, such rays being caught and reflected on to the plates by means
of transparent mirrors placed at a proper angle within the camera and at suitable
distances behind the lens. Thus I may place within the camera three transparent
or semi-transparent mirrors, or two transparent and one silver mirror at an angle
of 45° (approximately) at different distances behind the lens, and three sensitive
plates side by side at a right angle to the focal plane of the lens, and at such
corresponding distances from the surface of the mirrors that the surfaces of all of
the plates shall be correctly in the focus of the lens. When the light forming the
image passes through the lens and strikes the surface of the first mirror, a portion
of such light is reflected, and forms an image in correct focus on the surface of one
of the sensitive plates and produces a picture. The other portion of the light rays
passes through the first mirror and strikes the inclined surface of the second mirror.
Here a further portion of the light is reflected and forms an image in correct
focus at the surface of the second sensitive plate. The residue of the light which
passes through the second mirror is reflected from the surface of the third mirror
(which need not be transparent) to the third sensitive plate placed at a proper
distance to ensure the image being in correct focus. In this way the three negatives
are produced at one and the same time by a single exposure. I place colour screens
of glass or other suitable material as required between the inclined mirrors and the
sensitive plates.
In practice I prefer to use only two mirrors both of which are transparent or
semi-transparent, and I make the said mirrors of plane sheets of glass one surface
of which is slightly silvered or platinised to avoid the difficulties or confusion
caused by double reflexion from the two surfaces of the glass. I prefer to use
these mirrors with the platinised or silvered surfaces next the lens, and I sometimes
protect the metallic surface with a thin coat of a suitable hard and transparent
varnish. The first mirror I place immediately behind the lens at an angle of 45°
(approximately) and as this mirror will reflect nearly half the total rays of light
which pass through the lens I use the light from the first mirror to form the
negative for the red sensation. I therefore interpose between this mirror and the
colour sensitive plate a suitable screen of orange-coloured glass or other suitable
material, the screen being placed preferably as close as possible to the surface of
the sensitive plate.
The second mirror I place at a similar angle and at such an increased distance
from the back of the lens as shall correspond with the size or width of the sensitive
plates and I use the light reflected from this second mirror to form the negative
of the green colour sensation, the rays being made to pass through a yellow or
green screen on to the sensitive plate. I use the light which passes through both
mirrors to form the negative of the blue or violet sensation and for the third
negative I used an ordinary plate placed upright in the focal plane of the lens at
the proper distance. Such plate is very feebly sensitive to the orange yellow and
red rays and may be used without a screen. I sometimes however cut off the
orange, yellow and red rays by a screen of blue or violet, or I make the second
mirror of blue or violet glass, which may be silvered or not: in the latter case any
reflection from the back of the glass will be of the same colour as the glass and
will be cut off or neutralized by the yellow screen used for the second negative.
By using two mirrors only, in the manner above described, I am enabled to use
a lens of shorter focus and thus obtain more light or shorter exposures and a wider
pictorial angle than would be possible when three or more mirrors are used.
I adjust the depth of colour of the screens used and also the speed of the plate
in such manner that in the same time each of the three negatives will have received
its proper exposure. I sometimes further modify the effects of the aforesaid
colour screens by using in combination therewith a supplementary screen or
screens in front of the lens or immediately behind the same.
The negatives may
be developed together or separately and the density of each arranged so as to give
the best results.

page_text: Stereoscopic pictures may be made in the same way by using two lenses at the
proper distance apart and a plate of suitable size.
I make from the completed negatives transparent positives by any ordinary
method and I view the positives so made as one picture by means of an apparatus
similar in construction to the camera aforesaid but furnished with an ordinary
magnifying eyepiece and a reflector or reflectors to control the lighting, or I
utilize the camera itself with these additions for viewing the positives.
Each of the transparent positives must be illuminated only by light of the colour
sensation which it represents. This can be done by using, in place of the colour
screens used for the negatives, screens of red, green and violet glass to correspond
with the fundamental colour sensations. I prefer however to mount each of the
positives in combination with a transparent medium of the colour required, for
example thin sheets of coloured gelatine placed in proximity with the positive and
backed and protected with ground glass. If required in addition to the ground
glass I use one or more thicknesses of semi-transparent paper or thin sheets of
celluloid or other suitable material having one or both surfaces treated to resemble
ground glass. I thus make each positive carry its own screen of the proper colour
and I am enabled to vary or modify the depth of tint or shade of the screens to
suit each particular positive of the subject and also the amount of light to show
the correct colours, and shades of colour in the picture which is formed by the
combined images of the positives. For convenience and in order that the visible
images from the three positives shall register and coincide with each other, I mount
each positive with its appropriate colour screen in a frame, preferably of wood,
(similar to an ordinary magic lantern slide) and I make these frames fit exactly
into their respective places in the camera or viewing instrument so that when the
set of three positive slides are placed in position the pictures will exactly register
and a single coloured image only will be seen.
It is obvious that a coloured picture may be printed from the three negatives
obtained by my improved apparatus by any of the ordinary three colour block
processes, with the further advantage that only one negative will need to be
reversed as the other two of the negatives which are taken by means of reflecting
mirrors are already reversed.
The coloured pictures obtained as I have described by means of my improved
apparatus may also be shewn by magic lantern projection in several ways. For
example the three positives with their own coloured screens but without the ground
glass may be placed in a triple lantern or three separate lanterns and the three
images thrown and exactly superimposed on the screen; or a single lautern may
be used, constructed with reflecting mirrors exactly in the same way as my
improved camera and fitted with three separate lamps and condensers, one for
each of the three positive pictures which are thus combined and thrown on the
screen through one and the same objective lens. In this way very perfect coloured
pictures may be shown by projection.
I however prefer to proceed as follows, that is to say, by means of the three
negatives I make coloured lantern slides complete in themselves so that they can
be shown in a single magic lantern of the ordinary construction. In making these
composite colour slides I first print two transparent positives on glass one of which
is preferably made from the non-reversed negative and I make the third transparent
positive not on glass but on a thin film of transparent celluloid or mica or other
suitable thin transparent material. The two glass positives are mounted face to
face in correct register with the positive on the thin film also in correct register
between them. By these means I make a triple lantern slide of no more than the
ordinary thickness, no cover glass being required as the images are on the inside
and they as well as the thin film positive are thus protected from injury. It is
obvious that the three positives must be printed in their appropriate colours and
as the slide is to be shown by white light the colours must be arranged to corre-
spond, and in this case the deposit or opaque parts of the different positives must be
in their respective complementary colours, for instance the negative representing

page_text: the red sensation must be printed in blue, the blue in yellow, and the green in
red. These colours may be obtained by chemically treating ordinary developed
plates so as to change the deposit to the desired colour or they may preferably be
printed in coloured gelatine, by the Woodbury process or by a modified gelatine
process similar to the carbon process. In any case I make one of the coloured
transparencies on a thin film, so that when placed in contact with the others they
can easily be adjusted in perfect register.
Date 10th day of Fohunane 1805
HASELTINE, LAKE & Co.,
15 Southampton Buildings, London, W.C., Agents for the Applicant,
Improvements in Colour Photographs, and Apparatus for Producing
and Viewing the same.
I, BENJAMIN JOSEPH EDWARDS, of The Grove, Hackney, in the County of
Middlesex, Manufacturer, 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:----
My invention relates to colour photographs (that is to say, photographic pictures
by means of which objects are represented in their natural colours), and to means
for producing and viewing such photographs.
By my invention the production and viewing of colour photographs is facilitated,
and the desired results are obtained by simpler means than have been heretofore
employed.
In carrying out my invention, I use what is known as the three colour system of
photography and I produce three negatives on colour sensitive plates each negative
being made to represent one of the three primary colour sensations. Thus the
negative to represent the red sensation is taken through a colour screen or light-
filter which cuts off all or the greater portion of those rays of light which do not
produce that sensation; the same is also done in making the negative to represent
the green sensation; and also in regard to the negative for the blue violet.
sensation.
I use for the negative of the red sensation, a colour screen of red or orange tint,
in conjunction with a plate which is sensitive to the rays which pass through such
a screen. For the negative to represent the green sensation I use a colour screen
which cuts off nearly all the blue and violet rays, in conjunction with a plate which
is sensitive to the green, yellow and orange rays; and for the negative of the blue or
violet sensation I use either a similar colour sensitive plate with a violet screen
or an ordinary plate which is chiefly sensitive to blue or violet rays either with
or without a screen to cut off the yellow rays. In this way I obtain three
photographic negatives, each of which represents one of the three fundamental
colour sensations by which we perceive all the colours in nature.
One way of viewing the representation of the object photographed so as to see
the same in the natural colours of the original is to make transparent positives from
the three negatives, and view them through appropriate screens which represent the
primary colour sensations corresponding to each positive. When the three
illumined positives are combined or superimposed by optical means so that they
are coincident, the lights and shades blend, and the eye sees one image in all the
original colours of the object. Printing blocks may be made from the three
negatives, and used to produce prints in their corresponding or complementary
colours the three impressions being superimposed give the various tints required
to produce the complete coloured picture,

page_text: According to the methods heretofore employed, the three negatives are taken on
separate plates by separate consecutive exposures; or three separate negatives are
obtained on one plate by a single exposure. By my improved method I take the
three negatives by one objective on three separate plates at one and the same time
by a single exposure. In this way I am able easily to produce colour photo-
graphs of many subjects which could not be easily photographed in colours by
other methods.
Referring to the accompanying drawings which illustrate my invention,
Figure 1 is a side elevation of a camera for taking pictures in accordance with
my invention.
Figure 2 is a vertical central section of the same.
Figure 3 is a vertical section of a part of the camera showing a focussing
screen in position.
Figure 4 is a perspective illustration of my improved viewing apparatus by
means of which transparent positives from the three negatives are optically com-
bined to form the coloured picture. The said figure also shows a box for
supporting the apparatus, and for receiving the same when not in use, and
Figure 5 is a plan illustrating my improved apparatus arranged as an optical
lantern for projecting coloured pictures on a screen.
Like letters of reference denote corresponding parts in the several figures.
My improved camera consists of a box or body A furnished with a lens or
objective B of the kind used in ordinary cameras, and constructed to carry three
separate sensitive plates C¹ C² C³ each of which receives an image formed by the
rays of light passing through the lens B. The plates C1 and C2 are arranged
to be at right angles to the focal plane of the objective B, and the plate C³ is
parallel to the focal plane of the lens. The rays striking the plates C', (2 are
reflected respectively from semi-transparent mirrors D1, D2 placed at a proper angle
within the camera and at suitable distances behind the lens, the plates being
arranged at such distances from the mirrors that the surfaces of the plates are
correctly in the focus of the lens. When the light forming the image passes
through the leus B and strikes the surface of the first mirror D¹, a portion of
such light is reflected, and forms an image on the surface of the sensitive plate C¹.
The other portion of the light rays passes through the mirror D' and strikes the
surface of the second mirror D². Here a further portion of the light is reflected
and forms a similar image on the surface of the second sensitive plate C². The
residue of the light which passes through the second mirror strikes the third
sensitive plate C3 and produces a third image. The relative distances of the three
plates from the lens B is such that when the position of the lens is adjusted
to produce an image in correct focus on any one of the plates, the images on the
other two plates will also be exactly in focus. In this way the three negatives
are produced at one and the same time by means of one lens, and by a single
exposure. I place colour screens E1, E2, E³ of glass or other suitable material as
required between the lens and the sensitive plates.
I sometimes arrange the third plate (3 parallel to the other plates C, C² in
which case I provide a third mirror to reflect the rays passing throug the second
mirror D² so as to cause them to strike the third plate. This third mirror may
be a non-transparent silvered mirror to ensure total reflection of all of the rays
that strike its surface. I prefer however the construction shown in the drawing
as that enables me to use an objective of shorter focus than would be possible were
three mirrors used.
I make the mirrors D', D² of plane sheet glass one surface of which is slightly
silvered or platinised or otherwise prepared to form a suitable semi-transparent
reflecting surface. By these means I avoid the difficulties or confusion which
would otherwise be caused by double reflections from the two surfaces of the glass.
I use these mirrors with their silvered or coated surfaces next the lens. I some-
times protect the said reflecting surfaces with a thin coat of a suitable hard and
transparent varnish. The first mirror D¹ I place immediately behind the lens

page_text: approximately at an angle of 45° and as I arrange this mirror to reflect nearly
half the total rays of light which pass through the lens I use the light reflected
from it to produce the negative for the red sensation. I therefore interpose
between this mirror and the colour sensitive plate ("a suitable screen E¹ of red
or orange-coloured glass or other suitable material, such screen being placed
preferably as close as possible to the surface of the sensitive plate as shown in the
drawing.
The second mirror D2 I place at a similar angle and at such an increased
distance from the back of the lens as may be rendered necessary by the size or
width of the sensitive plates and I use the light reflected from this second mirror
to produce the negative of the green colour sensation, the rays being made to pass
through a yellow or green screen E2 on to the sensitive plate (". I use the residue
of the light which passes through the mirror D2 to produce the negative of the
blue violet sensation upon the plate C³ placed upright at the proper distance from
the lens such negative may be made upon a colour sensitive plate by the aid of
a violet screen or without such screen upon an ordinary plate which is chiefly
sensitive to blue or violet rays as hereinabove described. I sometimes, while
dispensing with the screen, make the second mirror of blue or violet glass, which
may be silvered or not; in the latter case any reflection from the back of the glass
will be of the same colour as the glass and will be cut off or neutralized by the
screen used for the second negative. Such a coloured mirror may also be
advantageously used in the viewing or projecting instruments hereinafter described.
By using two mirrors only, in the manner above described, I am as hereinbefore
stated enabled to use a lens of shorter focus and thus obtain more light or shorter
exposures and a wider pictorial angle than would be possible were three or more
mirrors used. I adjust the depth of colour of the screens used, the density of the
coating on the mirrors, together with the " speed "of the plates in such manner
that in the same period of time each of the three negatives will have received its
proper exposure. I sometimes further modify the effects of the aforesaid colour
sereeus by using in combination therewith a supplementary screen or screens in
front of the lens or immediately behind the same.
For taking stereoscopic pictures I make the camera sufficiently wide to receive
two lenses at the proper distance apart and plates of suitable sizes and. I provide a
partition in the camera between the two lenses as is usually done in a binocular
camera. It is obvious however that stereoscopic pictures in colours may be made
by two of my improved cameras such as above described placed side by side.
I have shown the plates C, (2, ( placed in suitable dark slides F constructed
to slide in grooves ff. The colour screens E1, E2, E3 are mounted in frames G
constructed to slide in grooves g, I provide a focussing screen 11' Figure 3
which is mounted in a frame H constructed to fit in the grooves f, f that receive
the dark slides. The mirrors D', D2 may be conveniently arranged to slide in
grooves, in frames or carriages J. J which when properly adjusted are securely
fixed inside the camera. A Figure 1 is a door at the side of the camera to admit
of removing the mirrors when required for cleaning or for other purposes. It is
obvious that when the mirrors are so removed the camera can be used as an
ordinary camera. The lens B is secured to a board or plate B which is
connected to the body of the camera by bellows K and is adjustable by a rack
and pinion L1, L2 in the ordinary manner.
To produce photographs in colour by the aforesaid apparatus I proceed as
follows, that is to say, the focus being adjusted and the dark slides being
charged with suitable plates I expose the plates by uncovering the lens B for a
sufficient length of time to produce the three negatives. The negatives are then
developed together or separately and the density of each arranged to represent the
amount of light it has received through the screen corresponding to the colour
which it is to represent.
When the picture is to be viewed as a colour transparency I make from the
completed negatives transparent positives by any ordinary method and I view the

page_text: positives so made as one picture by means of an apparatus similar in construction
to the camera aforesaid but furnished with an ordinary magnifying eyepiece and a
reflector or reflectors to control the lighting, or I utilize the camera itself with
these additions for viewing the positives.
It
Figure 4 shows such an apparatus for viewing the three transparent positives.
The said apparatus is constructed substantially like the camera and is furnished
with two internal semi-transparent mirrors arranged like those in the camera.
is shown resting on an interior hinged lid M¹ of a box M. that serves to support it
and to contain the apparatus when not in use. The apparatus may be secured to
the lid by a screw. N is a reflector hinged to the box and so constructed that it
can be folded down on the lid M' when the apparatus is not in use. The reflector
may be formed of silvered glass or it may have a dead white reflecting surface.
Suitable hinged stays M². N are provided for supporting the lid and reflector
respectively at the required angles. M³ is a door to admit of inserting the
apparatus in the box. M' is a drawer for storing the transparent positives.
If
Each of the transparent positives must be illumined only by light of the
colour sensation which it represents. This can be done by using, in place of the
colour screens employed when producing the negatives, screens of red, green and
violet glass to correspond with the fundamental colour sensations. I prefer
however to mount each of the positives in combination with a transparent medium
of the colour required, for example thin sheets of suitably coloured gelatine placed
in proximity to the positive and backed and protected by ground glass.
required in addition to the ground glass I use one or more thicknesses of semi-
transparent paper or thin sheets of celluloid or other suitable material having one
or both surfaces treated to resemble ground glass. I thus make each positive
carry its own screen of the proper colour and I am enabled to vary or modify the
depth of tint or shade of the screens and the luminosity of the colours to suit each
particular positive of the subject and also the amount of light to show the correct
colours, and shades of colour in the picture which is formed by the combined
images of the positives. For convenience and in order that the visible images
from the three positives shall register and coincide with each other, I mount each
positive with its appropriate colour screen in a frame P, Figure 4, made of metal
or wood (similar to an ordinary magic lantern slide) and I make these frames to fit
exactly into their respective places in the viewing instrument and so adjust and fix
the transparencies in the frames that when the set of three positive slides are
placed in position, the pictures will always be in exact register and a single
coloured image only will be seen.
It is obvious that a coloured picture may be printed from the three negatives
obtained by my improved apparatus by any of the ordinary three colour block
processes, with the further advantage that only one negative will need to be
reversed as the other two of the negatives which are taken by means of reflecting
mirrors are already reversed.
For
The coloured pictures obtained as I have described by means of my improved
apparatus may also be shewn by magic lantern projection in several ways.
example the three positives with their own coloured screens but without the
ground glass may be placed in a triple lantern or in three separate lanterns, and
the three images thrown and exactly superimposed on the screen; or a single
apparatus may be used, constructed with reflecting mirrors similar to my improved
camera and fitted with three separate lamps and condensers, one for each of the
three positive pictures which are thus combined and thrown on the screen through
one and the same objective lens. Such an apparatus is shown in Figure 5. The
apparatus similar to the camera is denoted by Q. Q, Qare the reflecting mirrors.
R1, R2, R3 are the three lamps furnished with condensers S. In this way very
perfect coloured pictures may be shown by projection.
Sometimes I fix these three lamps in their respective positions in a complete
lantern body of suitable construction to which the camera or viewing instrument

page_text: can be temporarily attached by hooks or otherwise. Or I may have one lantern
body for two of the lamps and a separate lantern body for the third lamp.
As will thus be seen, the camera is so constructed that it can be used not only
as a camera for producing the negatives but also as a viewing apparatus and in
conjunction with the detachable lamps and condensers as a projection lantern for
the composite colour photograph, thus securing in the instrument greater efficiency
economy and convenience than has been heretofore obtained.
Sometimes by means of the three negatives I make colour lanterns slides
complete in themselves so that they can be shown in a single magic lantern of the
ordinary construction. In making these composite colour slides I first print two
transparent positives on glass one of which is preferably made from the non-
reversed negative and I make the third transparent positive not on glass but on a
thin film of transparent celluloid or mica or other suitable thin transparent
material. The two glass positives are mounted face to face in correct register
with the positive on the thin film also in correct register between them. By these
means I make a triple lantern slide of no more than the ordinary thickness, no
cover glass being required as the images are on the inside and they as well as the
thin film positive are thus fully protected. It is obvious that the three positives
must be printed in their appropriate colours and as the slide is to be shown by
white light the colours must be arranged to correspond, and in this case the
deposit or opaque parts of the different positives must be in their respective
complementary colours which the negatives represent, for instance the negative
representing the red sensation must be printed in blue, the blue in yellow, and
the green in red. These colours may be obtained by chemically treating ordinary
developed plates so as to change the deposit to the desired colour or they may
preferably be printed, in coloured gelatine, by the Woodbury process or by a
modified gelatine process similar to the carbon process. In any case I make one
of the coloured transparencies ou a thin film, so that when placed in contact
with the others all of the transparencies can easily be adjusted in perfect
register.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what 1
claim is:
1. The method substantially as herein described of simultaneously producing
three separate negatives on three separate plates by means of one lens, for the
purpose specified.
2. The camera substantially as herein shown and described fitted with, three
dark slides, one objective, and two semi-transparent mirrors, for the purpose
specified.
3. The herein described camera fitted with three dark slides, one objective,
and three reflecting mirrors for producing three separate negatives with one
exposure.
4. In an apparatus for producing and viewing composite colour photographs,
the combination with one or more semi-transparent mirrors of a mirror made of
coloured glass, substantially as, and for the purpose, specified.
5. The stereoscopic camera fitted with mirrors as herein described and for the
purpose specified.
6. An apparatus for viewing composite colour photographs said apparatus being
constructed to receive three transparent positives with their appropriate colour
screens and being furnished with mirrors, substantially as described, and for the
purpose specified.
7. A stereoscopic apparatus for viewing composite stereoscopic colour photo-
graphs, said apparatus being constructed to receive three stereoscopic transparent
positives with their appropriate colour screens and being furnished with mirrors,
substantially as described and for the purpose specified.

page_text: 8. An optical lantern fitted with mirrors to shew three transparencies with
their appropriate colour screens as one coloured picture. substantially as
described.
9. An apparatus such as that herein described which can be used as a camera
for producing three negatives and which can also be used for viewing as a colour
photograph the positives made from said negatives, or in combination with
suitable lamps and condensers can be used for projecting the said positives on a
screen as a colour photograph.
10. The combination with a transparent positive of a transparent coloured
screen with or without sheets of semi-transparent material for modifying the depth
of tint or shade of the screens and the luminosity of the colours, all mounted in one
frame and protected by ground glass if required, substantially as, and for the
purpose, specified.
11. A composite colour lantern slide made from two transparent positives
printed on glass, one of them being non-reversed, and a third transparent positive
on a thin film of transparent material placed in correct register between the glass
positives. each positive being printed in its appropriate colour. substantially as
described.
Total 1: 101
n100%
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.