Apparatus to be employed in Photographing Developments of Circular or other Surfaces not Visible from a Single Point of View.
Year: 1894

page_text: Date of Application, 15th Aug., 1894
Complete Specification Left, 15th May, 1895-Accepted, 22nd June, 1895
PROVISIONAL SPECIFICATION.
Apparatus to be employed in Photographing Developments of
Circular or other Surfaces not Visible from a Single Point
of View.
I ARTHUR HAMILTON SMITH of Riverbank Putney in the County of London
Gentleman do hereby declare the nature of this invention to be as follows
The object of my invention is to provide apparatus by means of which a photograph
can be taken shewing the whole or any desired part of the surfaces of cylindrical or
other objects having surfaces not visible from a single point of view.
An apparatus constructed according to my invention consists of a slitted screen
capable of being moved across the field of view of the lens of a camera and of a
support for the object to be photographed which support is operated in such a
manner that the object is caused to travel with the screen and at the same time to
have motion imparted to it in such a way that various portions of its surface or of
any desired part of its surface are successively presented before the slit in the
I do not limit
screen as it and the object are traversed in front of the camera.
myself to precise details but a convenient arrangement for the purpose of photo-
graphing from objects with cylindrical surfaces consists of a blackened screen
capable of being moved by a screw in guides situated transversely of the axis of
the lens of the camera. The said screen is provided with a suitable hood and a
cloth or the like extending from the screen to the camera.
In the screen is
a vertical slit the side or sides of which can be moved and clamped so as to vary
the width of the slit.
At the back of the screen is a frame, which can be rigidly connected with the
parts constituting the groove supporting the screen. At the requisite distance
from the screen, guides are fixed parallel with the screen and between these guides
is a disc, capable of rotation about its axis and of longitudinal motion between the
guides. A short cylinder or piu stands concentrically on the disc and above is a
plate in the centre of which rises a small pin. A hole passes through the axis of
the cylinder and a hole at a corresponding height, passes through the screen
immediately below the centre of the screen and through these holes a rigid rod or
lever passes one end being free and the other end being centred on a pivot whose
position can be adjusted.
A series of discs of various diameters in accordance with the diameters of the
objects to be photographed are provided, they having holes in their centres to fit
on the pin in the aforesaid plate.
At each side of the framework are clamps, capable of holding a cord at the height
of the middle of the disc when placed on the pin and capable of being fixed at any
desired distance from the screen.
A disc of the same diameter as the cylinder to be photographed is placed on the
pin, a cord is passed from a clamp round the disc, and thence to a second clamp.
The cord preferably joins and leaves the circumference at the point nearest to the
screen and the whole is adjusted so that the cylinder is at the proper distance from
the screen.
The cylinder is placed on the wooden disc so that the part which is to
form the middle of the photograph is nearest to the screen, when in the axis of the
camera lens. The lever is pivotted below but a short distance behind the optical
centre of the lens when the camera is in position...

page_text: It will be obvious that if the screen be moved to right or left, the lever causes.
the disc between the parallel guides to move therein so as to follow the screen and
also causes the disc which is confined by the cord to rotate to a corresponding-
extent together with the object placed on it.
The screen is now drawn aside until the part of the cylinder which it is wished
shall be at one side of the picture is thrown upon the ground glass of the camera
in its proper position.
The dark slide is now exposed and by means of the screw the slit in the screen
is made to travel across the field of view of the camera lens and the object seen
through it thus travels across the sensitive plate in the camera in the opposite
direction. At the same time the lever actuated by the screen moves the disc
between the parallel guides and the revolution of the disc actuated by the cord
causes successive portions of the circumference of the cylinder to present them-
selves to the lens through the slit as it assumes its successive positions and thus the
image of the surface of the cylinder is unwound or "developed" and photographed
on the sensitive plate.
If it be desired to photograph a portion of a cone the object may be tilted until
the smaller circumference is vertically above one point, or if there be two important.
points in the design vertically above two points in the design. The size of the disc
will be that of the circle which passes most nearly through the points of intersection
and near the important parts of the design. Parts of the design which fall outside
the disc are compressed on the sensitised plate, and parts which fall within it are
spread out. In arranging the compromise necessary for developing a figure other
than a cylinder, it is necessary to consider the character of the design and the parts
where accurate rendering is most desired.
If the surface of the object be spherical or spheroidal it is advantageous to place
the pivot on the opposite side of the screen beyond the object. The effect of this
is that the smaller circumferences of the sphere, are for any given arc spread out
over a shorter distance than the principal circumference while they are spread
out over a longer distance than the principal circumference, if the lever is pivotted
below or behind the lens. I have described the application of my invention to the
photographing of cylindrical or circular surfaces but it is not restricted thereto as
it may be also applied to the photographing of developments of other surfaces, the
mechanism by which the articles to be photographed is operated being so arranged
that as the screen moves across the field of view of the camera lens and the article
to be photographed is similarly moved its surfaces are successively presented
before the slit as hereinbefore described.
Dated this 15th day of August 1801
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, Agents.
COMPLETE SPECIFICATION.
Apparatus to be employed in Photographing Developments of
Circular or other Surfaces not Visible from a Single Point
of View.
I, ARTHUR HAMILTON SMITH of Riverbank, Putney, in the County of London,
Gentleman, 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 object of my invention is to provide apparatus by means of which a
photograph can be taken showing the whole or any desired part of the surfaces of
cylindrical or other objects having surfaces not visible from a single point of view.
An apparatus constructed according to my invention consists of a slitted screen

page_text: capable of being moved across the field of view of the lens of a camera and of a
support for the object to be photographed which support is operated in such
a manner that the object is caused to travel with the screen and at the same time.
to have motion imparted to it in such a way that various portions of its surface or
of any desired part of its surface are successively presented before the slit in the
screen as it and the object are traversed in front of the camera.
I do not limit
myself to precise details but I will describe with reference to the accompanying
drawings a convenient arrangement for the purpose of photographing from objects
with cylindrical surfaces from which its application to articles of other shapes will
also be readily understood.
Figure 1 is a longitudinal section. Figure 2 a front elevation and Figure 3 a
plan of the apparatus.
Figure 4 is a plan of a modified arrangement. A is a blackened screen carried
by a base piece A' capable of being moved by a screw B (engaging with a screw
nut b secured to the base A2) in guides C situated transversely of the axis of the
lens of the camera D. At the back of the screen A is provided a suitable hood E
and supports E for a cloth or the like extending from the screen to the camera to
exclude the light.
In the screen A is a vertical slit a the side or sides of which
can be moved so as to vary the width of the slit. A convenient arrangement for
adjusting the width of the slit a is shewn in Figure 2. It consists of two sliding
strips or shutters 662 operated by cords c c² at the upper and lower ends. Each of
the cords c is connected at one end to one of the shutters bat e and passes round a
pulley d its opposite end being connected to the shutter 62 at 2 whilst the ends
of the cords are also connected to the shutters at e and 2 and pass round
pulleys d so that when one of the shutters or 2 is moved in either direction the
other shutter will be moved in the reverse direction to the same extent and so
The
be.
maintain the slit a in a central position whatever the width thereof may
hood E is connected to a frame F at the back of the screen and to the base C
constituting the guide in which the screen moves. At the requisite distance from
the screen A are guides G arranged parallel to the screen and between these guides
is fitted to slide longitudinally a piece H having projecting from its upper end &
stud or pin g on which is mounted a disc h so as to turn thereon. On this disc /
the object to be photographed is placed. A hole passes horizontally through the
piece H a similar hole being provided at a corresponding height in the centre line
of the screen through which holes a rigid rod I passes one end of the said rod
being free and the other end being connected to a pivot i on an adjustable bar K
the position of which pivot can be adjusted as required by moving the bar K in or
out to a greater or lesser degree. A series of discs h of various diameters to suit
the diameters of the objects to be photographed are provided, they having holes in
their centres to fit on the stud or pin g on the aforesaid piece H and each disc may
be provided on its periphery with two or more grooves of different depths to suit
articles of different diameter.
At each side of the framework constituting the guides G are clamps k capable
of holding a cord L at a height corresponding or approximately corresponding to
the position of the grooves in the disc h when placed on the pin g.
A disc having
a groove in its periphery corresponding in diameter to the
diameter of the cylinder to be photographed is placed on the pin g and the cord L
is passed from one clamp round the said groove in the disc and thence to the
second clamp k. The cord joins and leaves the circumference of the groove on the
disch at the point nearest to the screen and the frame constituting the guides G
and carrying the disc and the object to be photographed is adjusted on the main
frame or support M so as to bring the object to the proper distance from the
screen A. The object to be photographed is placed on the disc so that the part
which is to form the middle of the photograph is nearest to the screen when in the
axis of the camera lens. The rod I is pivotted below, but a short distance behind
the optical centre of the lens when the camera is in position. It will be obvious
that if the screen be moved to the right or to the left, the rod I causes the piece H

page_text: carrying the object to follow the screen and also causes the disc h which is confined
by the cord L to rotate to a corresponding extent together with the object placed
on it.
The screen is now drawn aside until the part of the object which it is wished
shall be at one side of the picture is thrown in its proper position upon the ground
glass of the camera.
The dark slide is now exposed and by means of the screw B, the screen is
traversed in its guides C, the slit a being thus caused to travel across the field of
view of the caniera leus, and the object seen through it thus travels across the
sensitive plate in the camera in the opposite direction. At the same time the rod I
actuated by the movement of the screen moves the piece H between the parallel
guides G and the revolution of the disc h caused by the cord L makes successive
portions of the circumference of the object present themselves to the lens through
the slit as it assumes its successive positions and thus the image of the surface of
the object is unwound or "developed" and photographed on the sensitive plate.
On the outer end of the rod I in a wheel or pulley which runs on a sheet or
plate preferably of glass the said pulley supporting the outer end of the rod so as
to reduce the friction of the piece H in the guides G.
If the surface of the object be spherical or spheroidal, it is advantageous to
place the pivot i on which the rod I turns on the opposite side or front of the
screen beyond the object as shewn diagrammatically in Figure 3A for which
purpose the bar K carrying the said pivot is capable of being withdrawn from its
support in the base C, and reinserted from the front of the screen. The effect of
this is that the smaller circumferences of the sphere, are for any giving arc
spread out over a shorter distance than the principal circumference y as indicated
by the dotted lines 2 y2 while when the pivot i is behind the screen as in
Figures 1, 2 and 3 the smaller circumference is spread out over a longer distance
than the principal circumference.
Instead of causing the object to be photographed, to move in a rectilineal
direction in front of the screen as herein before described it may be caused to
traverse in a curved direction the piece H on which the object is mounted being
caused to move along a curved guide G Figure 4 and the cord L by which rotation
is given to the object being placed in a groove in the curved edge of the said
guide G.
If it be desired to photograph a portion of a cone the object may he tilted until
a point in the smaller circumference is vertically above a point in the larger
circumference or if there be two important points in the design then until at those
two points the surface of the cone coincides or nearly coincides with points in an
imaginary cylinder erected on the disc h. The size of the disc will be that of the
circle which passes most nearly through the points of intersection and near the
important parts of the design. Parts of the design which fall outside the disc are
compressed on the sensitised plate and parts which fall within it are spread out.
In arranging the compromise necessary for developing a figure other than a
cylinder, it is necessary to consider the character of the design and the parts where
accurate rendering is most desired and adjust the object and movement accordingly.
I have described the application of my invention to the photographing of
cylindrical or circular surfaces but it is not restricted thereto as it may be also
applied to the photographing of developments of other surfaces the mechanism
by which the article to be photographed is operated being so arranged that as
the screen moves across the field of view of the camera lens and the article to
be photographed is similarly moved its surfaces are successively presented before
the slit as herein before described.
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 I
claim is :-
1. In apparatus for use in photographing developments of circular or other

page_text: surfaces not visible from a single point of view the combination with a photographic
camera of a slitted screen and means for traversing it across the field of view of the
lens of the camera, a support for the object to be photographed and means for
operating the said support so that the said object is caused to travel with the said
screen and means for imparting motion to the said object in such a way that
various portions of its surface or any desired part of its surface are successively
presented before the slit in the screen as the said screen and the object are
traversed in front of the camera substantially as hereinbefore described.
2. In apparatus for the purpose described the combination with a photographic
camera of a slitted screen and means for traversing it across the field of view of
the lens, a support for the object to be photographed, a pivotted rod by means of
which the support is connected to the screen and caused to travel therewith, a stud
or pin projecting from the support; a disc mounted on the stud or pin and
receiving motion of rotation by means of a cord or the like surrounding the disc
and having its ends fixed so that as the support is traversed with the screen, the
said cord or the like imparts rotation to the said disc and so to the object
placed thereon substantially as hereinbefore described.
3. The combination and arrangement of parts constituting apparatus for
photographing developments of circular or other surfaces not visible from a
single point of view, substantially as hereinbefore described and illustrated by
Figures 1, 2 and 3 of the accompanying drawings and also the modification thereof
illustrated by Figure 4.
Dated this 15th day of May 1895.
JOHNSONS & WILLCOX,
Agents.