Improvements in Apparatus for Taking, Projecting, or Inspecting Series of Photographs.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Taking, Projecting, or Inspecting
Series of Photographs.
:-
I, WILLIAM BRITAIN, Junior, of 28, Lambton Road, Hornsey Rise, London, N.,
Manufacturer do hereby declare the nature of this invention to be as follows:-
One of the objects of this invention is to enable an apparatus for taking and
for projecting series of photographs to so take and project the same that there
is no interval of darkness or interruption in the taking or projecting of the series
that is to say between the taking or projecting of any one photograph of the
series and the next photograph thereof, and also no appreciable variation in the
intensity or quantity of light during the taking or projecting respectively so
far as the light is being utilized in the taking or projecting of any one photograph
of a series. By attaining this purpose the objectionable flickering of the conse-
cutive series of images hitherto found with instruments of this class and due to
alternate illumination and obscuration is avoided, and the images appear to the
eye to be of continuous duration always equally and uniformly lighted.
A further object, which is also to some extent an incidental advantage of the
above principle, is to increase the length of the period of exposure of each indi-
vidual photograph by which means increased detail is obtained in the photograph
so far as stationary objects are concerned or those whose movement is sufficiently
slight during the period of exposure as to escape detection. By this means also,
and especially when coupled with the continuous and uninterrupted exposure
of the series as a whole, I am enabled to, indeed, turn to advantage the blur of
moving objects which others have sought to avoid or overcome, and utilize this
blurr for the accurate reproduction of moving objects to the eye as they are in
fact seen by the eye in nature.
A further object, and one also partly incidental to the above advantages is to
enable fewer photographs to be taken per second and thus enable the size of each
to be enlarged more than is possible with other systems based upon intermittent
projection, and as will hereinafter be seen I am also enabled to reduce the speed
of the film bearing the series of photographs by the principle of construction
involved in the production of the apparatus to give continuous projection in the
sense in which it is to be understood in this description.
A further object and one which with the longer exposure of negative film
obtainable with this invention, I believe to be brought within practical limits is
the projection of the series of photographs so that the image shall appear in the
colors of nature.
With these objects in view, my invention is based upon principles of the fol-
lowing nature; A mirror is so combined with a drum or its equivalent and a
lens or suitable combination of lenses, that the axis of rotation of the drum lies
in the reflecting surface of the mirror and the mirror moves upon said axis at half
the rotary speed of the drum. By a drum is here understood any device which

page_text: will carry part of a movable film and cause the same to follow a path which
contains an arc of a circle having its centre in the fixed axis of the moving mirror.
It will be understood therefore that if a beam of light is projected for example
from a condenser through, the film upon the mirror the latter will reflect it to
the lens, and during the movement of the film and mirror (the latter moving at
only half the speed of the film) the same part of the film will continue to be
reflected to the lens without any lengthening or shortening of the path of any
ray from any part of the film reflected by said mirror to the lens, so that from a
moving film a stationary image, stationary in all its parts, is obtained or vice
versa, a certain view is photographed onto a moving film during a certain duration
of its movement.
As it is obvious that after such projection onto or from a moving film during
the passage of the particular part thereof which gives or receives the image
through the before mentioned arc, it is necessary to discontinue the projection
and to recommence the same onto or from the next following portion of the same
film to create or reproduce the succeeding image or picture, there will be an
interval of darkness or non reproduction during the time taken by the mirror
to revert to its first position, which is preferably done by oscillation of the mirror.
To avoid the appearance of this interval I prefer to duplicate the apparatus,
having thus two mirrors working alternately, two lens or combinations for photo-
graphic or projection purposes and a suitable source of light, if for projection,
also preferably in duplicate. The film band is then provided with two series of
photographs, or with one series arranged in two lines and alternating one with
the other and I provide a shutter of such nature that it alternately covers each
of the lenses leaving the other open in such a way that there is always illumina-
tion through one or the other lens that is to say a continuous projection of images
through the two lenses alternately.
This multiplication could be carried further and if desired overlapping may
occur, that is to say one projector may be unshuttered before another is shuttered
and in this manner representations in natural colors might be obtained by a com-
bination of several such projectors with their several mirrors and lines of photo-
graphs on the films, and suitable colored screens for projection of three colors,
similar devices with possibly lighter screens being used in the photography of the
original object as are hereinafter referred to for the photography. of objects in
monochrome.
As it is desirable to take each photograph of a series from exactly the same
standpoint that is to say through one lens only and not alternately through two
lenses and as it is required as aforesaid to project the images alternately into
two lines on the film, I may employ a suitable arrangement of mirrors and shutters
or of movable reflecting shutters acting also as mirrors and other stationary
mirrors for reflecting images alternately as before mentioned care being taken
that the length of passage of equivalent rays to the two (or it may be more) places
where the images are to be thrown on the film shall always be equal in order to
strictly preserve the same scale of representation.
In respect of the apparatus necessary for the above objects, it is obvious that
various methods of obtaining the desired movements may be employed and the
following is therefore mentioned as an example only.
To carry the film I may use two wheels having cogs to engage holes in the
edges of the film as is well known, and the film may be led thereto by suitable
rollers so as to remain in contact with the wheels during about one sixth of their
circumference. Between the wheels are the mirrors which may be moved at the
half speed of the wheels by accurately made crown wheels the teeth of which
act by means of intermediate levers on levers attached to the mirrors or their
axes respectively such intermediate levers having fixed abutments so that half
speed movement only is given to the mirrors the same being capable of adjust-
ment. When the teeth trip the intermediate levers the mirrors are returned
by springs.

page_text: Rectilinear lenses are preferably used and cross movements are given them for
exactly superposing the images on the screen.
By the use of a monocular eye piece and a similar shutter or mirror system
to that used in taking the photographs the apparatus serves for exhibiting such
films by inspection.
Dated this 4th day of Februar 1899
Improvements in Apparatus for Taking, Projecting, or Inspecting
Series of Photographs.
I, WILLIAM BRITAIN, Junior; of 28, Lambton Road, Hornsey Rise, London, N.,
England, Manufacturer, do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement:-
One of the objects of this invention is to enable an apparatus for taking and
for projecting series of photographs to so take and project the same that there
is no interval of darkness or interruption in the taking or projecting of any one
photograph of the series and the next photograph thereof, and also no appreciable
variation in the intensity or quantity of light during the taking or projecting
respectively so far as the light is being utilized in the taking or projecting of any
one photograph of a series. By attaining this purpose the objectionable flickering
of the consecutive series of images hitherto found with instruments of this class
and due to alternate illumination and obscuration is avoided, and the images
appear to the eye to be continuous and always equally and uniformly light.
A further object, which is also to some extent an incidental advantage of the
above principle, is to increase the length of the period of exposure of each indi-
vidual photograph by which means increased detail is obtained in the photograph
so far as stationary objects are concerned or those whose movement is sufficiently
slight during the period of exposure to escape detection. By this means also,
and especially when combined with the continuous and uninterrupted exposure
of the series as a whole, I am enabled to, indeed, turn to advantage the blurr of
moving objects which others have sought to avoid or overcome, and utilize this
blurr for the accurate reproduction of moving objects to the eye as they are in
fact seen by the eye in nature.
A further object, and one also partly incidental to the above advantages is to
enable fewer photographs to be taken per second and thus enable the size of each
to be larger than is possible with other systems based upon intermittent
projection, and as will hereinafter appear I am also enabled to reduce the speed
of the film bearing the series of photographs by the principle of construction
involved in the production of the apparatus to give continuous projection in the
Sense in which it is to be understood in this description.
A further object is to enable the film to be continuously and uniformly moved
during exposure and projection with which movement there is less strain on the
film than when intermittent movement is employed.
The means by which I preferably carry my invention into effect are illustrated
in the annexed drawings in which :-.
Fig. 1 is a plan view of the apparatus arranged for the taking of the photograph.
Fig. 2 is a plan view thereof, the case, the film, its carrying rollers, and the

page_text: Fig. 4 is a longitudinal vertical section on line 4-4 of Fig. 2 as seen in the
direction of the arrow a².
Fig. 5 is an end view of part of Fig. 2.
Fig. 6 is a longitudinal vertical section on line 6-6 of Fig. 2 as seen in the
direction of the arrow a.
Fig. 7 is a view on a larger scale showing in detail the mirror movement.
Fig. 8 is a front elevation partly in section of the apparatus when arranged for
projection.
Fig. 9 is a section on line 9-9 of Fig. 8, the film holding devices being
removed; and
Fig. 10 is a front elevation showing on a smaller scale the shutter used for
projection and indicated in dotted lines only in Fig. 8.
Fig. 11 is a section on line 11-11 of Fig. 10.
My invention is based upon principles of the following nature. A mirror is so
combined with a drum or its equivalent and a lens or suitable combination of
lenses that the axis of rotation of the drum lies in the reflecting surface of the
mirror and the mirror moves upon said axis at half the rotary speed of the drum.
By a drum is here understood any device which will carry part of a movable film
and cause the same to follow a path which contains an arc of a circle having its
centre in the fixed axis of the moving mirror.
1 and 2 are two side frames united by bolts and nuts. 5 is a plate parallel to
and midway between the frames 1, 2 from which it is spaced by lengths of tube 6
surrounding the bolts 3. Part of the plate 5 is cut away at 7 so as to form a
slide bed 8 in which either the shutter and lens attachment for taking the pictures
or the projecting lenses for projecting them may be slid and attached as hereinafter
described.
To the upper part of plate 5 is attached a bar 9 parallel to the bed 8 for
assistance in guiding the aforesaid attachments. To the plate 5 are attached, for
example by lugs 10 and screws 11, screens 12, 13 the side walls 14, 14, 15, 15, of
which carry the shafts of rollers 16, 17, 18, 19. 20 is a shaft journalled in the
end frames 1,2 carrying the pinions 21, 22 gearing respectively with the toothed
peripheries 23, 24 of the wheels 25, 26. These wheels are parallel to and equal
to one another and on their flanges 27 28 are pins 29 which engage the perfora-
tions 30 near the edges of the film 50 for the purpose of moving the film across
the space between the wheels 25, 26. The wheels 25, 26 are journalled on the
hollow shafts 32 carried respectively by the side frames 1, 2 and by the stan-
dards 31 (Fig. 6). The wheels 25, 26 have naves 33 of suitable length to have
bearing along the shafts 32 respectively.
Within each shaft 32 is a rod 34, movable longitudinally, and adapted to be
fixed by a set screw 35, the inner end of the rod serving as a pivot bearing for
the axle of the mirror. There are two such mirrors 36, 37 on opposite sides of
which are the pivots 38, 39 having bearing respectively in the ends of the rods 34
aforesaid and in a boss 40 on the middle plate 5.
Mechanism is provided to move the mirrors 36, 37 in a rotary manner on their
axes, with an angular speed equal to half the angular speed of rotary movement
of the wheels 25, 26. A convenient mechanism by which the mirrors are posi-
tively moved by the motion of the wheels 25, 26 is as follows:-On the inner
faces of the flanges 27, 28 of the wheels 25, 26 are projections, preferably made
by extending the alternate pins 29 of each flange so that they project inwards
beyond the face of the flange as at 47 (Figs. 6 and 7). Concentrically with the
wheels 25, 26 there are pivoted levens 41, 41 respectively, connected by
rods 42, 42 to levers 43, 43 rocking on rods 44, 44 rigidly connected to the
mirrors.
The levers 43, 43 have two arms of equal length and they are connected by

page_text: rods 45, 45 to stationary arms 46, 46. The rods 45 are equal in length to the
rods 42 and the pivotal points of rods 42 on levers 41 are at the same distance
from the axis of the mirrors as the pivotal points of rods 45 on the arms 46.
The angular movement of the levers 41 is thus transferred at
exactly half speed to the mirrors respectively. At the end of each
lever 41, is a spring controlled hook 48 adapted to engage the pins 47 as
they pass over it and be carried along with cach, thus carrying the lever 41 with
the wheel 25 or 26 until the hook is tripped, for example by the cord 480 where-
upon a spring such as 49 returns the lever 41 and with it the mirror quickly to
its initial position.
As the pins 47 are not alligned on both wheels 25, 26 but are alternated, the
phases of the one mirror will also alternate with the phases of the other. It
will be understood therefore that if a beam of light is projected for example from
the lens upon one
of the mirrors the latter will reflect it to the
film, and during the movement of the film and mirror (the latter
moving at only half the speed of the film) the same part of the film will continue
to receive the same ray without any lengthening or shortening of the path of that
ray from the lens to the film, so that a certain view can be photographed on to a
moving film during a certain duration of its movement, or from a moving film
a stationary image, stationary in all its parts can be projected.
It is obvious that after such projection on to or from a moving film during the
passage of the particular part thereof which receives or gives the image through
the before-mentioned arc, it is necessary to discontinue the projection and to
recommence the same on to or from the next following portion of the same film
in order to create or reproduce the succeeding image or picture. There will be
an interval of darkness or non-reproduction during the time taken by the mirror
to revert to its first position. To avoid the appearance of this interval I have
preferred to duplicate the apparatus as I have assumed to be the case in the fore-
going description, having thus two mirrors working alternately, two lenses or
combinations for photographic or projection purposes and a suitable source of
light, if for projection, also preferably in duplicate. The film band is then pro-
vided with two series of photographs or in other words with one series arranged
alternately in two lines and alternating one with the other.
As it is desirable to take each photograph of a series from exactly the same
stand-point that is to say through one lens only and not alternately through two
lenses, and as it is required as aforesaid to project the images alternately into
two lines on the film I employ a suitable arrangement of mirrors and shutters
or of movable reflecting shutters acting also as mirrors and other stationary
mirrors for reflecting images alternately as before mentioned, care being taken
that the length of passage of equivalent rays to the places where the images are
to be thrown on the film shall always be equal in order to strictly preserve the
same scale of representation.
The photographic lens and shutter attachment, best seen in position in Figs. 2
and 4 comprises a base plate 51 supported on two forked legs 52, 52 the forked
ends of which straddle the part 8 of the plate 5 and are fixable in lateral adjust-
ment by abutment set screws 53 on one side and clamping screws 54 on the other
side. An upwardly directed forked arm 55 is similarly fixable on the bar 9. On
the base plate 51 is the mount of the photographic objective 56 the field of which
is cut by the rotary shutter 57. Behind the objective and in a plane to which
the axis of the objective is inclined at an angle of 45 degrees is a rotary mirror 58,
partly cut away and forming also a shutter. Parallel to mirror 58 is the
stationary mirror 59 and at right angles thereto the mirrors 60 and 61 parallel to
each other.
The shaft 20 drives the shaft 62 through bevelled gear 63, 64 and the latter
drives the shaft 65 through bevelled gear 66, 67. The shaft 65 drives the
shaft 68 through bevelled gear 69, 70: The shaft 68 carries the shutter 57 and

page_text: also drives the shaft 71 of the mirror 58 through the bevelled gear 72, 73 so that
the mirror 58 revolves at half the speed of the shutter 57. The bevelled wheels 63,
64, 66 67, 69, 70 are so proportioned that the shutter 57 makes one revolution
during a part revolution of wheels 25, 26 equivalent to the length of film equal to
half of one picture. The shutter 57 and the mirror 58 are semicircles and at each
revolution of the shutter 57 the mirror will be alternately in such position as
either to reflect the rays to mirror 59 and thus to mirror 36 or to allow the rays
to freely pass to mirror 60 whence they are reflected to mirror 61 and thence to
mirror 37.
The outer end of the shaft 65 is supported in a bearing in the side of a collar 74
which is formed at the end of the bracket 75. The hub 76 of the bevelled
wheel 66 is throated to revolve, in said collar 74 without endwise motion therein.
The bevelled wheel 66 can slide loosely longitudinally of the shaft 62 but is
attachable thereto by the set screw 76 which may be screwed to
up
the
flat part 77 of shaft 62. This arrangement permits of the bevelled gearing 66, 67
being removed and replaced when the whole photographic lens and mirror fitting
is removed or replaced.
engage
To carry the film I may use two rollers 19, 16 loosely mounted on their
shafts 78, 79 and having frictional engagement therewith by springs 80 (Fig. 8),
to compensate for difference in diameter at different stages of winding. The film
roller 19 may be led under suitable rollers 18, 17 and over part of wheels 25, 26
so as to remain in contact with the wheels 25, 26 over about one sixth of their
circumference.
The film is then wound on roller 16. To the latter motion may be given by
means of belt 81 passing round pulley 83 on the part 82 of the shaft 78 and
round pulley 34 on shaft 20 (Fig. 1). The rollers 16, 19 have slots 85 (Fig. 8)
for engagement of the ends of the films, and to enable the rollers 16, 19 to be
easily inserted and removed, the shafts 78, 79 may be made as illustrated for
shaft 78 in Fig. 8 namely so as to be capable of being drawn out by knob or the
like 85 so as to leave the roller free to be taken from the shield 14 or 15. The
end of shaft 78 engages in a recess in shaft 82 in such a way as to be positively
iurned with said shaft 82.
When the above described apparatus is used for the taking of a series of photo-
graphs it is enclosed in a suitable light tight case 84 (Fig. 4) the lens mount
flange 85 engaging the end of a bellows extension 85 so that light may not enter
the case from the orifice 87 therein except through the lens.
The apparatus is operated by crank handle 88 the shaft 89 of which in this
instance is passed from outside through an orifice in the side of the case to engage
the end of shaft 90 whence pulley 91 and crossed belt 92 convey motion to
pulley 93 on a shaft 20.
By the use of a monocular eye piece and a similar shutter or mirror system
to that used in taking the photographs the apparatus serves for exhibiting such
films by inspection if the latter are suitably illuminated.
Figs. 8-11 illustrate the attachments for use in projecting with this invention.
In place of the photographic lens and mirror attachment, which is removed, the
projecting attachment comprising the two objectives 94, 95 is inserted in a
similar manner. The mounts 96, 97 of the objectives 94, 95 each have lugs 98,
carrying a shaft 99 supported in pivotal bearings 100, 101 in arms 102, 103
adiating from a central shaft 104 supported in pivotal bearings 105, 106 in the
end frame 107, 108 attached to each other by bars 109, 110 and forked to engage
the parts 8 and 111 of the plate 5 in somewhat the same manner as the former
attachment.
Rocking adjustment can be given to the pair of objectives by the
screws 112, 113 in the arm 114 forming part with shaft 104. Rocking adjustment
can be given to each objective separately by screws 115, 116 engaging nuts 117,
118 in lugs 119 at the top of each mount 96, 97.

page_text: On the shaft 62 is now fixed the shutter 120 (Figs. 9, 10, 11) shown in dotted
lines in Fig. 8.
It has the two open spaces 121, 122, each covering an are of 180 degrees.and
corresponding to the position of the respective objectives 94, 95 as shown in Fig. 8.
From any suitable source, light is projected through condensers 123, 121
through the film 50 to the mirrors 36, 37 and thence to objectives 94, 95.
It being of importance to have the mirrors 36, 37 to work exactly, I prefer to
make the rods 42, 45 work upon pivots similar to knife-edges, and furthermore
to make at least one of the lever arms of lever 43 adjustable by making the forked
knife edge pivot 125 against which one of the rods 42, 45 engages, so that it may
be adjusted more or less from the fulcrum of the lever 43 for example by making
this pivot 125 on a sliding bar 126 guided in the lever 43 and having a lug 130
riding on a screw threaded pin 127 fixed to the lever on which its position is
adjusted by two nuts 128, 129. Springs 131, 132, 133, 134 hold the rods 42, 45
seated in the knife edges 125, 135, 136, 137. It will be understood however that
other constructions may be readily used for ensuring accuracy or working of the
mirrors, and that my invention is not confined to the use of the means herein
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. The combination of means for moving a photographic film through a seg
ment of a cylinder, a plane mirror having the axis of said cylinder in its reflecting
surface, means for giving a rotary movement to said mirror in one direction about
said axis, the velocity of said rotary movement being equal to half the angular
velocity of the movement of the film, and means for giving a practically instan
taneous return movement to said mirror to bring it to its initial position.
2. The combination of a drum having means for engagement of a photographic
film, means for revolving said drum, a plane mirror having the axis of said
cylinder in its reflecting plane, and means for giving rotary movement to said
mirror about said axis, the velocity of said rotary movement being equal to half
the angular velocity of the movement of the drum.
3. The combination of a drum having means for engagement of a photographie
film, means for revolving said drum, a plane mirror having the axis of said
cylinder in its reflecting surface, means for giving a rotary movement to said
mirror in one direction about said axis, the velocity of said rotary movement
being equal to half the angular velocity of the movement of the drum and means
for giving a quick return movement to said mirror to bring it to its initial
position.
4. The combination of two parallel wheels 25, 26 having means for engage.
ment of a photographic film, a plane mirror having the axes of said wheels in its
reflecting plane, and means for giving rotary movement to said mirror about said
axis, the velocity of said rotary movement being equal to half thd angular velo
city of the movement of the wheels.
5. The combination of means for moving a photographic film through a seg
ment of a cylinder, a pair of plane mirrors having the axis of
said cylinder in their reflecting plane and means for alternately giving
rotary movement to each of said mirrors about said axis; the velocity of said
rotary movement being equal to half the angular velocity of the movement of
the film.
6. The combination of means for moving a photographie film through a segment
of a cylinder, a pair of plane mirrors having the axis of said cylinder in their
reflecting surfaces, means for alternately giving a rotary movement to each of said
mirrors in one direction about said axis, the velocity of said rotary movement
being equal to half the angular velocity of the movement of the film, and means

page_text: for giving a quick return movement to cach of said mirrors to bring it to its
initial position.
7. The combination with a drum, means for revolving the same, a series of
projections 47 therein; a pivoted arm 41 a trip hook 480 on said arm adapted to
engage the projections 47, means for tripping said hook after it has passed
through a predetermined distance; an oscillatory mirror, an arm 44, two armed
lever 43 fulcrumed on arm 44, a stationary attachment, and connectors 42, 45,
connecting the lever 43 to arm 41 and to the stationary attachment respectively,
whereby angular movement is given to the mirror with a velocity equal to half
that of the drum upon engagement of hook 480 with one of the projections 47,
and means for returning the mirror and its attached parts to their initial posi-
tion on the tripping of hook 480.
8. The combination of two parallel wheels 25, 26 adapted to carry a photo-
graphic film, means for driving said wheels, two mirrors mounted side by side
between said wheels, a lens, a rotary part shutter at an angle of 45 degrees to
the axis of the lens and having a reflecting surface, a mirror parallel thereto, a
mirror at right angles to said shutter and a mirror parallel to the last named
mirror, whereby the image from said lens is alternately reflected to the right and
the left hand portions of the film.
9. The combination with means for moving a kinematograph film of a mirror
mounted to oscillate upon an axis lying in its reflecting surface, an arm integral
with said mirror, a two armed lever 43 fulcrummed on said arm, a lever 41
having its pivotal axis in the axis of said mirror, a connector for connecting the
lever 41 to one arm of the lever 43, a stationary attachment and a connector for
connecting the said attachment to the other arm of the lever, 43 means for engag-
ing and positively moving the lever 41 in accordance with the movement of the
film, means for tripping said lever 41 and means for returning the latter to its
normal position.
10. The combination with means for moving a kinematograph. film of a mirror
mounted to oscillate upon an axis lying in its reflecting surface, an arm integral
with said mirror, a two armed lever 43 fulcrummed on said arm, a lever 41
having its pivotal axis in the axis of said mirror, a connector for connecting the
lever 41 to one arm of the lever 43, a stationary attachment and a connector for
connecting the said attachment to the other arm of the lever 43, means for
engaging and positively moving the lever 41 in accordance with the movement of
the film, means for tripping said lever 41 and a spring for returning the lever 41
and parts connected therewith, substantially instantaneously to their normal
position.
11. The improved kinematographic exposure and projection apparatus sub-
stantially as herein described and illustrated in the annexed drawings.
1000
HERBERT HADDAN & Co.,
Agents to Applicant, 18, Buckingham Street, Strand, W.C., London.