Improvements in Cinematographs for Taking and Projecting Photographs in Colours.
Year: 1899

page_text: Date of Application, 30th Nov., 1899
Complete Specification Left. 29th Aug., 1900-Accepted, 3rd Nov., 1900
Improvements in Cinematographs for Taking and Projecting
Photographs in Colours.
WILLIAM NORMAN LASCELLES DAVIDSON, Captain 4th Bn. "The King's" (Liver-
pool Regiment), 17, Chesham Place, Brighton, Sussex, do hereby declare the
nature of this invention to be as follows:-
..
This invention relates to improvements in cinematographs (or other similar
instruments) for taking and projecting moving pictures in colours by means of
the three colour process." The instrument consists of certain mechanical parts
for moving the sensitive film the necessary correct distance after (or before) each
exposure and the capacity for exposing a large number of films. The lens is a
rectilinear working at an aperture of 15 (or larger). The screens or light filters
are three glasses, celluloid or other media of the suitable and correct colours for
the purpose as red, blue-violet, green or yellow. These screens revolve at the
back of the lens, or just in front of the sensitive film (or they may be fixed in
the three different sized diaphragms of the lens) which diaphragms will also
revolve or slide with the change of film. In either case the screens are made to
revolve or slide either at the back, front, or between the combinations of the
lens, so that when the apparatus is put into motion to photograph an object,
the screens, red, blue & green revolve or slide into position in time with the
change of film and release of the exposing shutter. The sensitive film behind
the colour screens require different periods of exposure, that is to say, the image
taken through the red screen may require thrice the exposure of the blue screen,
This is accom-
and the green (or yellow) screen twice that of the blue screen.
plished by causing the speed of the shutter to vary automatically in the above
(or any other) proportions; or the simpler way is to
cause the "
stops" or
diaphragms of the three different apertures, to drop into position after or before
each exposure between the combinations of the lens (in the case of a rectilinear),
and in front when using a single" view lens, so as to limit the action of light
in any required proportion automatically. It will be seen by this that the act of
winding the film, (or making exposures,) the film, colour screens, and the
different sized stops as well as the shutter will work automatically and in exact
time with each other. To view the resulting pictures it is only necessary to make
positives" from the negatives and to cause the colour screens to revolve or slide
with its complimentary positive to give the colour effect. Or if the screens are
not used the positives may be dyed to the correct colours complimentary to the
colour screens.
66
W. N. LASCELLES DAVIDSON,
Capt. 4th Bn. "The King's" (L'pool Regt.)

page_text: Improvements in Cinematographs for Taking and Projecting
Photographs in Colours.
I, WILLIAM NORMAN LASCELLES DAVIDSON, Captain 4th Bn. The Kings (Liver-
poor Regiment), 17, Chesham Place, Brighton, Sussex, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be particu-
larly described and ascertained in and by the following statement:-
This invention relates to cinematographs or like instruments for taking and
projecting moving pictures, and enables such pictures to appear in colours by
means of the three colour process.
According to my invention successive exposures are taken behind different
coloured screens, three in number according to the usual method, so that in the
complete series of negatives every third exposure is taken behind the same colour
'screen. To view the resulting pictures, positives are made which may be dyed
to the correct colours complementary to the colour screens, or may be exposed
behind colour screens similar to those employed in taking the photographs, these
colour screens moving successively into position giving the effect of a moving
coloured picture.
The colour screens or light filters consist of three stained glasses or sheets of
celluloid or other transparent material coloured in the required manner. These
screens may revolve at the back of the lens or just in front of the sensitive film
or if three diaphragms are employed of different sizes they may be fixed in the
said diaphragms which revolve or slide at each exposure. In any case the screens
are made to revolve or slide either at the back or front or between the combina-
tions of the lens so that when the apparatus is put into motion to photograph an
object the screens successively of red, blue-violet and green or yellow colours
revolve or slide into position in time with the change of film and release of the
exposing shutter. To give different exposures to the sensitive film according to
the colour employed the colour screen may move in a variable manner as herein-
after described or the diaphragms of the three different apertures may be caused
to drop into position after or before each exposure to limit the action of light in
any required proportion.
By the arrangement employed, the film, colour screens and the different sized
.stops (if employed) as well as the shutter work automatically and in exact time
with each other.
The accompanying drawings show a method of applying my invention in con-
nection with a revolving shutter apparatus such as is at present employed, the
colour screens rotating immediately behind the shutter.
Fig. 1 is an elevation of part of the interior of a cinematograph apparatus
showing my colour screen fitted to the revolving shutter at present employed;
Fig. 2. is a similar view with the shutters and screens removed to show the
gearing;
Fig. 3 is an elevation with the case in section at right angles to Figs. 1 and 2;
and
Fig. 4 shows the different form of screen more especially suitable for repro-
ducing the photographs.
As the other parts of the apparatus are of any well known construction I have
shown only those parts which are necessary to an understanding of my invention.
A is the case of the apparatus which is placed in front of the camera or repro-
ducing apparatus and this case carries behind the lens aperture the revolving
shutter B which is turned at high speed by suitable mechanism. In the apparatus
shown the handle b serves to revolve the shutter, through the toothed gearing
and the worm wheels 3 one of which is upon the spindle of the revolving shutter.

page_text: These parts form no feature of my invention and the shutter B may be rotated in
any convenient manner.
in front of the revolving shutter is placed in three colour screen C having the
coloured transparent plates c of the three colours required fitted between the arms
forming the body of the screen. As already mentioned the body of the screen
may be formed of vulcanite or other light, opaque material.
This screen is carried by the detachable bracket D the end of which is bent down
and fixed by means of the plate d to the side of the case A. The bracket is
fixed so that the pivot of the screen is eccentric to the revolving shutter and to
adjust the tightness of the screen preventing it turning too freely the small nut.c
is employed which can tighten the screen to any required extent.
On the revolving shutter B I fix a pin b which projects from its surface to a
suitable height and is adapted to engage the corners of the three arms forming
my screen and to carry the screen round with the shutter the required distance
for each revolution. As the screen is eccentric to the shutter the pin engages
at each revolution with one arm, turns the screen over about one-third of a circle
before it disengages and at the next revolution operates on the succeeding arm.
Once in each revolution a fresh colour is thus brought behind the exposing
aperture the next exposure being through the succeeding colour and so on each
colour repeating at every third exposure.
By placing the pin b¹ on the exposing shutter in a certain position the revolv-
ing colour screens can be moved out of exposing position to bring the opaque
part behind the lens aperture after a certain short interval of time which could
be made to vary according to the colours by making the parts of the three colour
screen of different proportions. Or three pins such as 61 may be employed at
different heights to engage successively the arms of the three colour screen,
the position of the pins determining the exposure intervals of the respective
colours. Instead of these methods being employed equal exposures may be given.
and the blue and green screens may be made to equal the red screen in actinic
intensity by adding an extra screen of yellow or smoked glass or any other means
of equalising the colours may be employed.
The screen B shown in Fig. 4 acts in exactly the same manner as that
described, but I prefer it for use in reproducing photographs. It consists simply
of a disc of vulcanite or like material having the apertures 2 filled in with
coloured transparent material of different shades to the colours employed in the
photographic screen. The edge of the disc is notched at 63 and the pin on the
revolving shutter engages in these notches turning the screen as already described.
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 a cinematograph apparatus means for taking and projecting moving
pictures in colours, substantially as herein described.
(2) In a cinematograph apparatus, a three colour screen fitted behind the ex-
posure aperture and adapted to be moved to bring the three colours successively
into exposing position, one colour for each exposure, substantially as and for
the purposes specified.
(3) In a cinematograph apparatus a three colour exposure screen pivoted behind
or in front of the revolving shutter, having three apertures filled in with coloured
transparent material and means for turning the said screen to bring the colours
successively into exposing position as the shutter revolves, substantially as herein
described.
1
1000
GEO. H. RAYNER,
37, Chancery Lane, London, Agent for the Applicant.