Improvements in Photography and in Photographic Apparatus.
Year: 1886

page_text: Date of Application, 30th Nov., 1886.
Specification Accepted, 25th Jan., 1887.
Improvements in Photography and in Photographic Apparatus.
I, ALFRED JULIUS BOULT of 323 High Holborn, in the County of Middlesex,
M.I.M.E. 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:
This invention has reference to apparatus for obtaining photographs under variable or
adverse circumstances being designed more especially for the purpose of enabling the
operator to procure portraits without the subject thereof being cognizant of the fact.
The apparatus consists essentially of a light tight camera or outer casing containing
an adjustable lens a holder for a sensitized plate or film and a drop or revolving
shutter having an adjustable opening through which a streak of light may be admitted
and caused to pass over the face of the film. Means are provided for focussing the
lens regulating the opening in the shutter and the rate of its motion and also for
changing the plate or film after each exposure.
In the accompanying drawings Figures 1 and 2 represent vertical sections of the
apparatus Figure 3 a plan thereof viewed from the under side the bottom being
removed and Figures 4, 5, and 6 details of certain parts of the adjusting mechanism.
Figures 7, 8 and 9 are respectively back, side, and front, elevation of the drop opened
to an unusual extent. A is the camera consisting of a box or case of rectangular
form having a removable bottom formed in one or more, preferably two paris such
as A¹ and A. In one end of the camera is a circular opening B to admit light a
sliding shutter B¹ being provided to close the opening when necessary. Opposite the
opening B is a lens fixed to the partition D; the lens is adjustable by rack and
pinion the spindle C being prolonged through the bottom of the box and provided
with a milled head in the usual manner. At the end of the camera opposite to that
occupied by the lens is space for the sensitized plate or film. This plate or film may
he inserted and taken out by removing the portion A¹ of the bottom of the camera.
The drop shutter which regulates the width of the streak of light and the duration of

page_text: its passage over the sensitized plate or film consists of two scoop shaped halves or
sections E and E' so formed as to overlap at the sides and front when the upper scoop
is inverted. They are composed of thin sheet metal blackened internally and are
pivoted together at one side upon the stud F and at the other upon the pin e the two
axes being in about the same horizontal plane as the centre of the lens C. In the
front portions of the shutter which are nearest the lens the material is cut away so as
to leave when placed together an oval aperture O for the admission of light. In order
to distribute the light over the full width of the plate the sides of the shutter are
expanded towards the back as shown in Figure 3. The upper section E is fast to the
stud F which passes through a collar F and is provided with a disc G milled at the
edge and notched or perforated on the face. Through the stud F passes a pin the
outer end of which carries an index or pointer and the inner end carries a crank
plate F2 to the crank pin F3 of which is pivoted a rod 1 which carries at its other
end a pin which passes through a slot E' in the upper section of the shutter and
through an open ended slot E³ formed on the lower section by means of the rect-
angular strip of metal E secured to the side thereof which lower section is mounted
loosely on the stud F and therefore at liberty to move independently of the upper
section E. The slots E and E³ form an angle between them consequently if the
pins be moved in one direction or the other the distance between the free ends of
the sections E and E¹ will be varied. With the pin at one extremity of the slots the
sections will meet and allow no light to pass as shown in Fig. 1. In Fig. 2 the pin is
at the opposite extreme and the sections are wide apart. By turning the index over
the face of the disc G motion is communicated to the crank plate and through the
rod F to the pin thus enabling the operator to adjust the width of aperture between
the sections without opening the camera.
In order to retain the shutter in its elevated position as shown in Figure 1 a boss H
is attached to the upper section E the pin e passing through the axis thereof. The
boss carries a flange H on the periphery of which are two notches h. A plate J
secured to the side of the camera carries two lugs between which is pivotted a three
armed lever K. A spring K' acting on one arm of the lever forces the central arm k
against the periphery of the flange H₁ thereby causing it to enter one of the notches h
when it comes into position suitable therefore. This occurs when the drop shutter is
in either of the top or bottom positions shown in Figures 1 and 2. In order to release
the shutter the operator presses on the button L which bears on the arm ¹ of the
lever K and compressing the spring K₁ the arm & being forced out of the notch in the
flange H thus allowing the shutter to fall or enabling the operator to raise the same
by turning the milled disc G.
At
In order to regulate the speed of the descent of the shutter a brake is applied to the
flange H consisting of two elastic metal straps M attached to a bracket M¹. The
straps partially encircle the flange H¹ and their free ends are drawn together by means
of the screwed rod M² the lower strap bearing against a shoulder m on the said rod
the threaded end of which screws into a nut m¹ attached to the upper strap M.
the bottom of the rod M is a circular knob or disc m having notches m³ at opposite
sides thereof. The rod M² extends downwards until it nearly reaches the portion A²
of the bottom of the camera through which passes a stud N carrying on its inner end
a circular plate n of about the same size as the disc m² and carrying two pins n¹ corre-
sponding in position with the notches in the disc m². The outer end of the stud N carries
a small crank handle N¹. When the portion A2 of the bottom of the camera is placed
in position the two pins n' enter the notches m³ and thus afford a means of turning the
screwed rod M without opening the camera. The restraining action of the brake M
is augmented by the use of a helical spring P one end of which is attached to a
collar P on the stud F and the other to the top of the camera.
Previous to taking the impression the parts of the apparatus are in the position
shown in Figure 1, and the operator by means of the index f¹ lowers the section E¹ of
the shutter until he obtains a suitable slot or opening for the passage of light the
extent of the opening being proportioned according to the light at the time of exposure.

page_text: When about to use the apparatus he focusses the object according to his judgement
and presses the button L'allowing the shutter to fall.
In order that no light may pass through the shutter and be reflected on to the
sensitized plate or film previous to and at the termination of the operation a light tight
guide curved to the radius of the shutter is placed immediately in front of the plate.
After the shutter has fallen it may be secured by means of a locking catch or turn
button R which enters an elongated loop R¹ formed on the lower half E¹ of the
shutter.
The exposure opening of the shutter is brought within a very short distance from
the sensitized surface so that a well defined bar or streak of light is shot on to the
plate this is very different from the effect produced by the various forms of instan-
taneous drop shutters at present in use whether placed between the lense and the plate
or outside the lense or (in the case of double lenses) between the lenses.
It will thus be seen that the whole of the sensitized plate is not exposed at one time
but that the light is admitted to it in the form of a bar or streak which commencing
at one part of the plate travels over it until the whole has been covered.
It will be understood that a shutter in a single piece or with the two portions
rigidly connected might be used but as the width of the oblong opening at the plate
end would not be adjustable this shutter would be suitable for one strength of light
only and the utility of the instrument would be reduced by employing such
construction.
Having now particularly described and ascertained the nature of the said invention
as communicated to me by my foreign correspondent and in what manner the same is
to be performed I declare that what I claim is :-
1. In photography the method substantially as specified of exposing the sensitized
plate or surface consisting in directing on to it a streak or bar of light which travels
over the whole surface upon which the image is to be produced.
as
2. In a photographic camera a pivoted drop shutter provided with an opening such
adapted to the shape of the lense and the movement of the shutter at one end and
an oblong opening at the other substantially as and for the purpose specified.
3. In a photographic camera provided with a double shutter the combination of the
disc F rod and pin the latter working in the angularly disposed slots E² and E³
for varying the oblong opening in the said shutter in manner substantially as shown
and described.
4. In a photographic camera the combination with a pivoted drop shutter formed in
two sections such as E and E of mechanism for increasing or diminishing the size of
the oblong opening Z thereof substantially as specified.
5. In a photographic camera the combination with a drop shutter such as described
of apparatus such as notched flange H¹ lever K and spring for retaining and press
button L for releasing the same substantially as specified and illustrated in Figures 4,
5 and 6 of the accompanying drawings.
6. In a photographic camera the combination with a drop shutter such as described
of a brake such as M and spring such as P either separately or conjointly for the
purpose of retarding the descent of the drop shutter substantially as specified.
7. In a photographic camera the combination with a drop shutter such as described
of a locking device such as R R¹ for securing the drop shutter after the exposure sub-
stantially as specified.
8. The complete photographic camera substantially as specified.