Apparatus for Developing Photographic Plates Without the Use of a Dark Chamber.
Year: 1897

page_text: Date of Application, 11th Jan., 1897-Accepted, 13th Feb., 1857
COMPLETE SPECIFICATION.
Apparatus for Developing Photographic Plates Without the Use of a
Dark Chamber.
I, HEINRICH BRUNO HELMERT of Körnerstrasse, Dresden, Germany,
Merchant, 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 provision of a dark chamber hitherto necessary for the developement of
photographic plates has been found by photographers, especially amateur photo-
graphers, to be a burden and a hindrance, because in a private residence such a
chamber is not always and in journeys seldom obtainable.
The object of the invention is to provide an apparatus by means of which
photographic plates may be developed in day light and in the light of electric,
gas, and other lamps and which is suitable for taking out of doors and upon
journeys, to enable the photographer to develope his plates immediately after and
at the place of taking the photographs or at hotels or the like without very great
inconvenience.
In the accompanying drawing
Figs. 1 and 2 are views of the lower part of the apparatus from two different
sides and Figs. 3 to 8 are sectional views of the same on line C-D of Fig. 1 at
different stages of use.
Fig. 9 is a vertical section on line A-B of Fig. 1.
Fig. 10 a side view of the upper part of the apparatus and Fig. 11 a sectional
view of the same on line E-F of Fig. 10.
The two main parts of the apparatus are each in the form of a casing, the
bottom of the upper casing being readily attached to and removed from the lower
casing.
a is the lower casing internally water tight and acid resisting from which, for the
purpose of developing photographic plates, the light may be excluded by means of
a slide working over an aperture c. d, e, are orifices for the introduction or
discharge of the requisite liquids or bath. f, g, are apertures to allow of obser-
vations, the former in the side of the casing and the latter opposite thereto in
the cover i, the meeting edges of which with the casing fit so as to prevent light
passing therethrough. Both of these observing apertures are closed by coloured
glass panes j, k, cemented in water tight, the former being dark red and forming
the bottom of the casing a when this is turned down, and the latter dark yellow.
m is a grooved frame extension of the casing in which is carried in front of the
red glass pane an opaque plate I capable of being adjusted in or wholly withdrawn
from said frame. Similarly there is carried in the cover i in front of the inspecting
aperture and the yellow glass pane k another red glass pane n in a grooved frame
extension o, in which it may be adjusted or from which it may be withdrawn.
P. 9, are tubular projections leading respectively from the orifices d, e, the former
closeable by a plug r and the latter having slid over it one end of an india rubber
tubes the other end of which is provided with a small funnel t closeable by a
plug u. Instead of the plugs r, u, cocks may be employed or instead of the plug u,
a device for pinching the india rubber tube s.
a is the upper and double casing employed in conjunction with the casing a and
serving for taking photographs in much the same way as with the means. hitherto

page_text: employed, only in addition to the large apertures through which the plates are
inserted and in addition to the slides w for closing said apertures, and with-
drawable to admit light to the plates, there are provided at the long narrow
side edges slits y through which the plates exposed to the light may be with-
drawn laterally from the casing and these slits are normally kept closed by means
of slides z.
In order to transfer a plate a exposed to the light from the casing a to the
casing a under exclusion of light the top edge 1 of casing a is reinforced or of extra
thickness and recessed in front of the slide b for the insertion of the casing a as
shewn in Figs. 3 and 4.
z
The apparatus is used in the following way :-For the purpose of developing
the plates exposed to the light in the double casing a', this is fixed in the recess 2
of casing a the cover or lid i of which must then be closed, the corresponding
slide is then drawn out, the plate & then falling on to the slide b which is then
also drawn out and the plate falls through the slit c into the casing a (Fig. 4),
whereupon the slides b, z, are slid back again and the two casings a, a, separated,
the former being laid on its side with the cover i uppermost, the plate a to be
developed then lying immersed in its bath (Fig. 5), which is introduced through
the india rubber tubes after removal of the plug u in a quantity sufficient to
immerse the plate but not to reach up to the edge of the slit c.
The tube s
being again closed and the casing a containing the plate laid in the horizontal
position, said casing is gently shaken to and fro to circulate the liquid but this
circulation or movement must not be so great as to cause the liquid to run into the
slit c and to the slide b.
The above operation may be performed in any light without any probability of
the plate being spoilt as the red and yellow glass panes render impossible any
injurious action of the rays of light upon the plate to be developed.
When it is desired to inspect the development of the plate, the slidel is drawn
out, and after the casing has been turned into the vertical position of Fig. 6, held
with the plate against the light, when the easing may be seen through and the
operator enabled to observe whether any further developement of the plate is
needed or whether it is completed. In the latter case the developing liquid is
poured out through the orifice d and outlet p and in its place clean water
supplied through the tube s, the casing being then shaken so as to induce a
washing action on the plate. This being done the water is discharged, the
fixing liquid then poured into the casing and after a sufficient action upon
the plate poured off in its turn whereupon the plate is ready for removal from
the casing.
In order that when the casing a is turned from the position of Fig. 5 to that of
Fig. 6 the liquid of the bath may not leak out between the edges of the casing
and the cover i an additional aud narrow sheet 3 of red glass cemented in
water tight at the end opposite to the slit c close underneath or against the
glass panek the width of this extra sheet of glass being such that the bath
will not come so high as its top edge (Fig. 6) when the casing is in the upright
position.
As the developed plate when, after the withdrawal of the slide b, it is simply
allowed to drop down through the slit c and removed after opening the cover i,
might receive scratches from the edges of the slit c or glass sheet 3, said plate
may be more safely removed by introducing into the casing a through the slit ca
smooth plate or thin sheet of glass and then turning the casing so that the
developed plate comes to lie upon the introduced plate or sheet and may be easily
removed through the slit c as shewn by way of example in Fig. 7.
To remove the second plate x from the casing a¹ to the casing a the position of
the former is reversed by placing it by its opposite end in the recess 2 and
proceeding in the same way as before.
In developing a plate by day or sun light it is advisable to have the red glass
pane n in its place over the yellow glass pane k in order to prevent any injurious

page_text: action of the rays of light upon the plate but in the presence of a weaker light,
say lamp light, both the slide and the red glass pane n may be gently withdrawn
either wholly or partially, so that by holding the casing to the light the finest
details of the picture may safely be observed during the developing process.
The development being finished and the plate removed from the casing a, this
after opening the cover i, may be cleaned out just as conveniently as the ordinary
developing trays or vessels.
The cover is carried on hinges 4 and is secured in the closed position by
means of a slotted hinge band 5 on the cover taking on to a knob or pin 6 fixed
in the casing. The cover may also be arranged to be wholly removable and
fixed in the closed position by bolts, clamps or other suitable fastenings.
To render the casing a watertight and acid resisting it may be coated over
with Japan varnish or the like, or a red glass casing may be inserted therein, the
bottom of which would replace the pane ; and the top edge be closed over as at 3
(Fig. 8) the side edges then running as shewn by the dotted line and an orifice
for the discharge of the liquid being provided.
As the double photographic casings at present in use, or obtainable, have no edge
slides such as it is not practicable to pass the plates to be developed immediately.
into the developing apparatus under exclusion of light, and therefore without
special means such old photographic casings cannot be used with the developing
apparatus of this invention. In order to surmount this difficulty a means is
provided by which plates may be passed from a casing of the old kind first into
a casing a such as shewn in Figs. 10, 11, and then out of this into the developing
casing as described. This means consists of a housing of which Figs. 12, 13,
are two different outside views and Figs. 14 to 20 different sectional views of the
sane with and without the new and old casings applied thereto. The housing is
so large and so formed as to receive the casing a and over this the old casing 7
in such a way that it quite excludes the light (Figs. 16, 17, 20).
The plates are transferred from the old casing 7 to the new casing a' by drawing
out the corresponding slides 8, w, of the two casings so that a plate will drop
from the old into the new casing (Fig. 17) whereupon the two slides 8, w, are
again closed, the casings taken out of the housing, each turned round or reversed,
again placed in the housing and the other plate passed in the same way from
the old into the new casing by the withdrawal of the corresponding slides 8, w.
9, 10, are the open sides of the housing for the introduction of the casings at
two different ends. By this arrangement the slide handles 11 for the respective
casings, being at opposite ends of the housing, may be conveniently discerned and
grasped.
The housing may also be constructed in one piece in which case a housing
would be required for each different size of old casings, but when in two pieces as
shewn only the upper part would have to be changed for the different sizes of old
casings, the bottom 'part always serving for a particular size of casing a¹.
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. Apparatus for the development of photographic plates comprising a casing a
provided with a closeable slit c for the introduction therein, under exclusion of
light, of the plates to be developed; orifices d, e, respectively for the withdrawal
and introduction of the bath liquid; a closeable recessed reinforcement 1 arranged
to permit the casing a from which the plates are to be withdrawn, to be placed
under exclusion of light in said casing a provided with dark coloured glass panes
or other transparent fields j, k, and with transparent or opaque slides l, n, which
from time to time may be opened to allow of inspection of the developing process,
whereby the suitably coloured glass panes prevent the action of the light rays
upon the plate, substantially as described and shewn.
2. A photographic case a¹ serving for use in conjunction with the developing

page_text: -case a and having in addition to one or more slides w closing an aperture or
apertures serving for the insertion of plates to be exposed to the light, also
one or two edge slides and held closed by these latter one or two slit like
apertures y through which plates exposed to the light may be discharged into the
developing casing a, substantially as described and shewn.
3. A housing serving for use in conjunction with the casings a, a', for enabling
photographic plates exposed to light to be transferred from such casings as are
not suitable for direct connection with the casing a into a casing suitable therefor,
and for this purpose is so constructed and formed that it can receive under exclusion
of light two casings one 7 of the ordinary kind and one a' constructed in accordance
with this invention, substantially as described and shewn.
Dated this 11th day of January 1897.
THOMAS R. SHILLITO,
89 Chancery Lane, London, W.C., Agent for the Applicant.