Improvements in Apparatus for Producing Light for Photographio purposes.
Year: 1899

page_text: Date of Application, 14th Nov., 1899
Complete Specification Left, 21st May, 1900-Accepted, 7th July, 1900
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Producing Light for Photographio
purposes.
We, WILLIAM HENRY SMITH, of 10, Aberdeen Road, Croydon, in the County of
Surrey, Works Manager, and WILLIAM WILLIS, of The Platinotype Engineering
Company, 22, Bloomsbury Street, in the County of London, do hereby declare
the nature of this invention to be as follows;-
Our invention relates to apparatus for producing light for photographic pur-
poses whereby a light is obtained of sufficient actinic value to act in place of
daylight, and when used for ordinary photographic studio work of sufficient power
to have the desired effect in a conveniently short space of time.
Various methods have been proposed and employed tor producing light for photo-
graphic purposes, for example, electric arc lamps, electric incandescent lamps,
incandescent gas burners, and lamps known as "flash lamps," in which metals or
other substances are burned, have been tried. All of these methods however,
as heretofore practised, have more or less objectionable features. For instance
arc lamps are expensive and troublesome to manage, electric incandescent lamps
are deficient in actinic rays, incandescent gas burners if male sufficiently powerful
for studio work are objectionable because of the great heat developed, and flash
lamps are dangerous by reason of their liability to set fire to inflammable objects
near them, besides which they are objectionable because of the diffusion through
the atmosphere of the studio or room of burnt and partially burnt products arising
from such lamps.
Moreover it is found in practice that au artificial light to be of any real value
must be strong enough to allow of its being reflected when necessary for proper
lighting" upon the object to be photographed instead of being thrown directly
upon such object.
It is known that magnesium or other suitable metal burned in oxygen gives.
a satisfactory light for photographic purposes, the rays being very actinic and
therefore adapted to be used after reflection for illuminating the object to be
photographed. The method heretofore used for producing such light
not how-
ever convenient for practical and repeated use, and the object of the present
invention is to provide simple and easily manipulated apparatus for burning
magnesium and other suitable metals in oxygen in an unobjectionable manner
and so as to form or give a sufficiently strong actinic light to be used where
necessary by reflection.
Our improved apparatus is portable and may be carried by a movable stand,
which can be raised and lowered as required.
An important feature of our invention is the provision of means for igniting
the metal ribbon or wire by a current of electricity, paper, sulphur, wax or other
readily inflammable substance being employed as hereinafter described to ensure
the ignition when the current is switched on.
Another important feature is the construction whereby the oxygen consumed

page_text: during combustion is replaced automatically by fresh oxygen from a suitable
source of supply.
A further feature of the invention is the construction whereby the combustion
of the metal takes place in a closed and tightly stoppered vessel containing a
small quantity of water which vessel is in communication with another vessel,
gas holder or floating bell, containing the oxygen supply, whereby no excessive
pressure can be generated in the combustion vessel, and at the same time the
products of combustion are confined and prevented from being diffused through
the atmosphere of the room or studio. The condensed combustion products
after each flash are taken up and mixed with the water contained in the vessel.
We will now describe a convenient form of apparatus embodying our invention.
The combustion takes place in a transparent or translucent vessel (which may
for isochromatic photography be made of suitably coloured glass) furnished with
a stopper from which depend two conductors which are in circuit with a battery
and a switch. The said conductors are joined by a third conductor of greater
resistance which becomes heated when the current is switched on. The magnesium
or other ribbon is fixed at one end in a suitable clamp carried by the stopper,
and the other end is maintained in contact with the thin conductor aforesaid
by twisting or otherwise. To ensure that the metal ribbon shall light up when
the thin conductor is heated, we wrap a suitable strip of paper round the junction
of the ribbon and conductor, or we apply sulphur, or wax or other readily
inflammable substance to the end of the ribbon. The aforesaid vessel is supported
on a table which can be raised and lowered as required on a tripod or other portable
stand which is also adapted to carry a container or reservoir for oxygen gas, which
may consist of a rising and falling bell or dome of any usual type. The said
container or reservoir is connected by a flexible tube with the flash or combustion
vessel, said tube being joined to a rigid tube which preferably enters the flash
vessel through a stoppered opening at the side, the rigid tube being so bent inside
the vessel that the water which is contained in the vessel cannot readily enter the
tube when the vessel is being shaken in order to absorb the condensed products of
combustion.
The action of this apparatus is as follows, that is to say, the container or reser-
voir being first filled with oxygen from any convenient supply the combustion
vessel is now placed in communication with it and filled with oxygen, the stopper
fitted with the conductors is then inserted and the current is switched on where-
upon the thin conductor becomes heated and the magnesium or other metal ribbon
or wire is lighted. The pressure induced by the sudden heating of the contents
of the combustion vessel momentarily forces back some oxygen into the container,
but this is followed by a return movement wherein fresh oxygen takes the place
of that consumed. The fumes or combustion products contained by the vessel
are then taken up and mixed with the water therein which process is facilitated
by shaking the vessel, after which the stopper can be removed and replaced by
a fresh stopper fitted with conductors and another piece of metal ribbon or wire.
A cock is provided to shut off the gas container when required. Also a reflector
is suitably placed behind the glass combustion vessel and carried by the same table
so that it rises and falls with the said vessel.
With this apparatus the fumes or combustion products do not enter the room
or studio, and there is no danger of blowing the stopper out, or of bursting the
vessel.
Stoppers may be constructed with more than one pair of conductors and fitted
with a corresponding number of pieces of magnesium or other metal wire or
ribbon so that successive combustions may be obtained without opening the vessel.
Dated this 14th day of November 1899.

page_text: Improvements in Apparatus for Producing Light for Photographic
purposes.
We, WILLIAM HENRY SMITH, of 10, Aberdeen Road, Croydon, in the County of
Surrey, Works Manager, and WILLIAM WILLIS, of The Platinotype Engineering
Company, 22, Bloomsbury Street, in the County of London, 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:
-
Our invention relates to apparatus for producing, for photographie purposes,
a light of sufficient actinic value to act in place of daylight, and when used for
ordinary photographic studio work, of sufficient power to have the desired effect
in a conveniently short space of time.
Various means have been proposed and employed for producing light for photo-
graphic purposes, for example, electric arc lamps, electric incandescent lamps,
incandescent gas burners, and lamps known as "flash lamps" in which metals or
other substances are burned. All of these methods however, as heretofore prac-
tised, have certain objectionable features. For instance, arc lamps are expensive
and troublesome to manage; electric incandescent lamps are deficient in actinic
rays; incandescent gas burners if made sufficiently powerful for studio work
develop too much heat; and flash lamps are dangerous by reason of their liability
to set fire to inflammable objects near them, besides which they are objectionable
because of the diffusion through the atmosphere of the studio or room of burnt
and partially burnt products arising from such lamps.
Moreover it is found in practice that an artificial light to be of any real value
must be strong enough to allow of its being reflected from a suitable surface or
filtered through a translucent screen, when necessary for proper "lighting," upon
the object to be photographed, instead of being thrown directly upon such object.
It is known that magnesium or other suitable metal burned in oxygen gives
a satisfactory light for photographic purposes, the rays being very actinic and
therefore adapted to be used, after reflection from or filtration through a screen,
for illuminating the object to be photographed. The method heretofore used
for producing such light is not however convenient for practical and repeated use,
and the object of the present invention is to provide simple and easily manipulated
and portable apparatus for burning magnesium and other suitable metals in oxygen
in an unobjectionable manner and so as to form or give a sufficiently strong
actinic light to be used where necessary by reflection or filtration.
An important feature of our invention is the provision of means for lighting
the metal ribbon or wire by a current of electricity, ignition being ensured by
means of paper, sulphur, wax or other readily inflammable substance as herein-
after described.
Another important feature is the construction whereby the oxygen consumed
during combustion is replaced automatically by fresh oxygen from a suitable
source of supply.
A further feature of the invention is the construction whereby the combustion
of the metal takes place in a closed and tightly stoppered vessel containing if
desired a small quantity of water, which vessel is in communication with another
vessel, gas holder or floating bell, of sufficient size, containing the oxygen supply.
whereby no excessive pressure can be generated in the combustion vessel, while
at the same time the products of combustion are confined and prevented from
being diffused through the atmosphere of the room or studio.
Referring to the accompanying drawings which illustrate our invention.

page_text: Figure 2 is a plan of a reflector hereinafter described.
Figure 3 is a vertical section of the illuminating vessel drawn to a larger
scale
'
Figure 4 is an edge view of the magnesium ribbon and clamp for holding same.
Figure 5 is a vertical section of a modified form of illuminating vessel containing
several magnesium ribbons, and
Figure 6 is a diagram of electrical connections suitable for firing the ribbons
successively.
Figures 7 and 8 illustrate further modifications hereinafter described.
Like letters of reference denote corresponding parts in the several figures.
Referring to Figures 1 to 4, A is a transparent or translucent vessel in which
the combustion takes place, and which, for isochromatic photography, may be
made of suitably coloured glass. The neck of the vessel is closed by a stopper a
of india rubber for example through which a pair of electric conductors B, B
are passed, said conductors being in circuit with a suitable source of electricity
and a switch or contact-making-push represented by C. The conductors B, B
are connected by a third conductor D secured by screws d or otherwise, the same
being a thin wire of high resistance which becomes heated when the current is
switched on. The magnesium or other ribbon E to be burned, is fixed at one
end in a clamp F carried by the stopper a and the other end is maintained in
contact with the thin conductor D in any suitable manner. To ensure that the
metal ribbon shall light up when the thin conductor is heated, a strip of paper,
saturated in nitrate of potash for example, may be wrapped round the junction
of the ribbon and conductor. This paper is ignited by the heated wire and serves
to ignite the magnesium with certainty. We find it convenient to form the strip
of igniting paper in the form of a hook e attached to the magnesium ribbon and
adapted to hook on the conductor D. In lieu of using paper as above described.
we may apply sulphur, wax, or other readily inflammable substance to the end
of the ribbon to ensure ignition. Moreover we find it advantageous to slit the
ribbon at the end for the same object.
The vessel A is supported on a table G which can be raised and lowered as
may be required, the same being carried for example by a telescopic tube y
which is shown connected by clamps to the outer case of a holder for containing
oxygen gas. Any other suitable form of portable stand may be provided for
supporting the vessel A. The gas holder may conveniently comprise a rising and
falling bell or dome of any usual type arranged in the outer case h. It is
connected to the vessel A by a flexible tube J which for convenience is joined to
a rigid tube that enters the vessel A, through a stopper al inserted in an
opening formed at the side of the said vessel, the rigid tube j being bent
upwards as shown so that the water which is sometimes used in the vessel A
to absorb the products of combustion, cannot readily enter the tube when the
vessel is being shaken.
The action of this apparatus is as follows, that is to say, the gas holder or
reservoir being first filled with oxygen gas from any convenient supply, the
combustion vessel A is now placed in communication with it by the tube J and
filled with oxygen. The stopper a fitted with the conductors B, B is then inserted
to close the neck of the vessel and the current is switched on whereupon the
thin conductor D becomes heated and the magnesium or other metal ribbon or
wire E is lighted. The pressure induced by the sudden heating of the contents
of the combustion vessel momentarily forces back some oxygen into the gas
container but this is followed by a return movement wherein fresh oxygen takes
the place of that consumed. The fumes or combustion products contained by
the vessel A are then absorbed by the water therein which process is facilitated
by shaking the vessel, after which the stopper a can be removed and replaced
by a fresh stopper fitted with conductors and another piece of metal ribbon or
wire ready for a second flash. A cock h³ is provided to shut off the gas container

page_text: to prevent escape of oxygen while the stopper a is removed or at other times
when required.
With this apparatus, the fumes or combustion products do not enter the room
or studio, and there is no danger of blowing the stopper out, or of bursting the
combustion vessel. If desired, the water can be dispensed with.
K is a curved reflecter carried by the telescopic tube or standard 9 and adjust-
ably arranged behind the combustion vessel A to throw the light in one direction
either through an adjustable muslin or other suitable filtering screen L before
reaching the object to be photographed, or upon a white soreen where it is
reflected upon the object to be photographed. In either case the object being
photographed, if a person or animal, is not startled by the flash and perfectly
natural expressions of face and feature can thus be obtained. The screen L is
shown adjustably mounted on the standard g.
In order to light up the sitter while focussing the camera, we provide for
example electric glow lamps M or other suitable lights within the reflector K.
The great advantage of this arrangement is that the light for focussing purposes
comes from the same direction as that used for taking the picture, and hence the
adiustment of the sitter can be effected with the utmost precision.
In lieu of the gas holder shown in Figure 1, an expansible gas bag or bellows P
Figure 8 may be used for the same purpose. Such a bag may be attached to a
cylinder or other vessel containing compressed gas whence the gas is allowed
to escape at a low pressure through the usual reducing valve provided on such
cylinders.
If it is desired to produce several combustions before the combustion vessel
is opened, we provide a number of conductors and magnesium ribbons arranged
between them, with means for firing the ribbons successively. One such arrange-
ment is shown in Figures 5 and 6 in which we provide for six successive com-
bustions without opening the combustion vessel. In this construction, the
vessel A is in the form of a bell clamped on a suitable hase by means of
screw clamps a'. The six conductors B pass through the base and they are
furnished with means such as screw clamps B at their upper ends by which
the thin conductor D to he heated is secured to them. One wire extending round
the six conductors B is used, the same being heated, ignited or fused in six
different places successively as hereinafter described. The magnesium ribbons E
are suspended in clamps F which depend from a plate N supported by a central
pillar n. and the said ribbons make contact with the several sections of the con-
ductor D as in the single arrangement above described. The electrical connec-
tions may be arranged as follows, that is to say, as indicated in Figure 6, the
conductors B are electrically connected respectively to terminals 0, 0, on a
switchboard having two switch arms 01, 0¹ operated by a common handle so that
contact is made with two terminals simultaneously. By providing seven ter-
minals O, connected as shown, any adjacent pair of said conductors can be switched
into circuit and the wire D connecting such conductors thereby heated, ignited
or fused.
In Figure 7 we have shown a modification of Figure 5 in which the bell is
provided with a large neck fitted with a stopper a from which the clamps for
holding the magnesium ribbons are suspended as in Figure 3. The clamps or
terminals B B are in this case mounted on a slate or other non-conducting
plate S which is suspended by means of a central tube R from the stopper. The
wire conductors leading to the terminals B¹, B' pass through the tube R so that
the conductors, terminals and ribbons are all carried by the stopper and are
removed and replaced together as in the first described arrangement. The
magnesium ribbons can thus be changed without requiring to raise the bell, and
therefore without wasting the oxygen. Escape of oxygen gas through the tube R
is prevented by packing the latter with any suitable packing material_T.
The pipe for conveying the oxygen to the bell is shown in both Figures 5
and 7 for convenience passing through the base a³.

page_text: Having now particularly described and ascertained, the nature of our, said
invention and in what manner the same is to be performed, we declare that, what
we claim is:
"
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1
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1. A flash lamp for photographic purposes, wherein the metal for producing
the light is consumed in a closed vessel that is in free communication with an
expansible gas-holder or reservoir, whereby the generation of excessive pressure
during combustion is avoided, and the products of combustion are confined and
prevented from being diffused through the atmosphere of the room or studio, sub-
stantially as described.
2. A portable flash lamp for burning metals in oxygen, so constructed that the
oxygen consumed during combustion is replaced automatically by fresh oxygen
from a source of supply of such gas, substantially as described.
3. In apparatus of the kind specified, the means substantially as described
for ensuring the ignition of the metal ribbon or wire when the electric conductor
is heated.
4. The combustion vessel in combination with the electric conductors and
means for holding the metal ribbon, constructed and arranged substantially as
described with reference to Figure 3 of the drawings.
5. The apparatus substantially as described with reference to Figures 1 to 4
of the drawings and operating as, and for the purposes, specified.
6. The modified form of combustion vessel with arrangements for holding and
lighting the metal ribbons substantially as described with reference to Figures 5
and 6 or to Figure 7, or to Figure 8, of the drawings.
-
Dated this 14th day of May 1900.
D. YOUNG & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicants.