IM- PROVEMENTS IN PHOTOGRAPHIC APPARATUS
Year: 1880

page_text: LETTERS PATENT to Thomas Henry Blair, of Franklin, County of Norfolk,
State of Massachusetts, United States of America, for the Invention of "IM-
PROVEMENTS IN PHOTOGRAPHIC APPARATUS."
COMPLETE SPECIFICATION filed by the said Thomas Henry Blair at the
Office of the Commissioners of Patents on the 4th February 1880.
THOMAS HENRY BLAIR, of Franklin, County of Norfolk, State of Massachusetts,
United States of America. "IMPROVEMENTS IN PHOTOGRAPHIC APPARATUS."
My present Invention relates to means for enabling the art of making photo-
graphic pictures by the "dry plate" process, to be carried on by amateurs or
persons having little knowledge of the art, as well as to greatly simplify the labor
of professional photographers by adapting to a camera mechanical devices, by
means of which the various manipulations of the camera and plates are carried on
entirely from the outside of the camera box, and the latter not necessarily opened
during the entire operation of adjusting the camera to the view, focusing the lens,
bringing the plate into position to be exposed, returning such plate to its case, etc.
The nature and operation of my improvements will be described hereafter. The
Drawings accompanying this Specification represent in Figure 1 a perspective
view, and in Figure 2 a vertical section of a camera embodying my improvements;
Figure 3 is a perspective view of the portable eye piece or adjuster; and Figure 4,
a perspective view of closing slide for camera box, when the plate box is in position
for exposing.
In such Drawings the box or case of the camera is shewn at A, and the lens at B,
the latter being affixed to the front C of the box A, and such front being detachable
from the remainder in order that it may be moved forward or extended when
occasion requires, such front C and the lens when advanced as stated being sup-
ported in an upright position by swinging brackets a, a, applied to opposite ends
of the box A, and adapted to turn on their pivots b, b, as shewn in Figure 1, a
curtain of dark stuff being employed between the camera box and the front C, to
exclude light from the interior of the former. One novel feature in my present
camera consists in a portable eye piece or adjuster as it may be termed, which, as
shewn in Figure 3 of the Drawings, is a small hood d of wood or metal having a

page_text: peep hole dat rear, and an opening e in front, which determines the boundary of
the view to be taken, the hood with its opening corresponding with the camera
and lens, and enabling the adjustment of the camera as to position to be effected
without looking through the lens, as has heretofore been universally practiced.
To avoid the labor and trouble of moving the entire camera about in determining
the view to be taken, the adjuster may be held in the hand and the view deter-
mined with it, and it then is to be, or may be secured to the top of the camera for
final adjustment of the latter, as shewn in Figure 1 of the Drawings. The front of
the adjuster or hood d is provided with an open frame or slide f, which determines
definitely the boundary of the picture, and corresponds to the size of the negative
plate to be used, and these slides are to vary in size with different sized negatives
and lenses. The camera is provided with the ordinary peep hole which may be
used if required, but with the adjuster it will not be necessary. The glass plates
are contained in a rectangular inverted box D, which is adapted to enter an
opening E in the rear upper part of the camera box, such plate box when not in
use being lowered into the interior of the camera through said opening which is
closed by a suitable slide, as shewn in Figure 2 of the Drawings, and when in use
is erected upon the top of the camera and over the opening, as shewn in Figure 1
of the Drawings.
The interior end walls of the plate box are grooved, as shewn at g, g, etc., and
each oppositely disposed pair of grooves serve to support a plate n, while at the
bottom of each groove upon one end of the box, I place a plate spring i, which is
secured at one end within the groove by a screw. Opposite the free end of each
spring I screw through the end of the plate box D a screw j, which abuts against
the spring, and by means of which the spring may be forced tightly up to the edge
of the plate, and by clamping the latter within the grooves securely hold it in
place. When a plate is to be lowered into the camera box below the screw is
retracted, and the pressure of the spring upon the plate relaxed, and the latter falls
by its own weight into the slide or carriage, which is shewn at F as disposed
within the camera box.
Heretofore the front part of the camera carrying the lens has been moveable
towards and away from the camera box carrying the object glass, or the negative
as the case may be.
In lieu of this construction I have adapted the slide or carrier, and arranged it
to slide to and fro of the camera box, with respect to the lens, thus moving the
object glass toward or away from the lens, in lieu of the lens with respect to the
glass, which enables me to adopt the automatic method of transferring the various
plates from their box to the carrier, or vice versa. I have added to the carrier
several features, as follows:-First, one or more springs applied to its rear side,
and so as to impinge against the plate, and press the latter forward against the
outer edges or boundaries of the upright grooves in the carriage in order to ensure
a uniform position of the plate with respect to the lens; secondly, I have added
to the under side of the carriage a thin bar or plate l, which extends rearward
through an opening m in the rear side of the camera box, and I engrave upon the
top of this bar a series of numerals 1, 2, 3, 4, etc., which correspond with like
numerals placed on the heads of the screws j, or upon the end of the plate box in
the immediate vicinity of such screw heads, the numerals on the bar being so ad-
justed with respect to the grooves in the said box, and with the screws that as the
bar, and with it the carriage is advanced, or retracted and stopped upon any one of
the numerals (taking the rear side of the camera box as a zero or starting point),
the grooves of the plate box corresponding to this numeral shall be directly over or
coincident with the grooves of the carriage, and so that if the plate contained in the
former groove is allowed to fall it will drop directly into and be supported in an
upright position by the carriage, without necessity on the part of the operator of
opening the camera box. The sliding movements of the bar and carriage are
effected by a pinion n' affixed to a shaft o disposed within a recess in the bottom
of the camera box, and having a head p outside of such box by which it may be

page_text: rotated, the pinion engaging a toothed rack c affixed to or cut upon the underside
of the bar, as shewn in Figure 2 of the Drawings. A clamp of any suitable
character may be combined with the shaft o to prevent accidental turning of the
latter. The bottom of the plate box is to be provided with a sliding bottom r,
which when the camera is in use is to be removed from the camera, and constitutes
a cover to such box.
As before stated the rear side of the camera box may be taken as a zero mark or
pointer, and the distance between the numerals on the bar are of course equal to
the distances between the grooves on the plate box.
In operating with this instrument the portable or removable adjuster is taken from
the wearer's pocket where it may usually be carried, and with it the picture to be
taken may be determined upon without recourse being had to the camera, and
when the picture or view is ascertained the " adjuster" is placed upon the top of
the plate box in suitable hasps 8, 8, arranged for its reception, as shown in Figure 1
of the Drawings, and the plate box placed upon the top of the camera and over the
opening, it being understood that the said plate box is filled with sensitized glass
plates adapted to photographing by the dry plate process.
The final and nice adjustment of the camera is now made by looking through
the adjuster, or if deemed desirable through the regular peep hole of the camera,
which is provided with a cover for closing it when not used. The focussing of the
lens is now accomplished in the usual manner, the cover of the peep hole of the
camera box being removed for the purpose, and subsequently replaced, and a mark
made upon the bar closely up to the face of the camera box, in order that the
carriage after being retracted to receive its plate may be advanced to the same
point (that is to the focus thus predetermined) without admitting light to the interior
of the camera. The adjustment or placing of the camera, and the focussing of the
lens being accomplished as stated, the carriage by means of the rack and pinion is
retracted until one of the plates in the plate box, for instance, that contained in
groove 6 coincides with the carriage, which result is determined by bringing the
numeral on the index bar corresponding to such plate, that is number 6, against the
face of the camera box, as before stated.
The sliding bottom of the plate box is now removed and the screw numbered 6
retracted, which releases the plate number 6, and the latter drops into the carriage
below. The carriage containing the sensitized plate is now advanced or retracted,
as the case may be until the plate is brought into focus, which is determined by
the mark previously made on the index bar as before stated, and the plate is
exposed and the negative obtained. After the plate has been exposed the proper
length of time, the carriage is now moved until the negative arrives below the
groove 6 in the plate box above, which is ascertained by bringing the mark 6 on
the index bar against the camera box, as before explained, when the entire instru-
ment is turned bottom up, and the negative drops back again into its original
position in the plate box, where it remains concealed from the light until removed
for the purpose of being developed.
The operations above explained are to be repeated until all the plates in the box
have been converted into negatives, or so many of them as may be required when
the sliding bottom of the box is replaced, and the latter removed from the camera
until such time as the negatives are to be developed. It will thus be seen that the
sensitized plates are by my method secluded from the light during the entire
process of taking the negatives. It will also be seen that by my Invention little or
nothing is left to the skill of the operator, as even the focusing of the lens, and the
time of exposure of the sensitized plate may be predetermined upon, and provided
for by rules adapted to varying conditions of weather, etc.; hence the only excercise
of judgment required on the part of the operator will be to select the view or
picture. By the use of the portable adjuster the interior of the camera is always
dark as the light is never admitted, while the camera itself need not be removed
about in the act of selecting or determining the view to be taken as this may be
done by the adjuster above. Another advantage of special importance to amateur

page_text: CLAIMS.
First. In photographic cameras the combination with the plate carrier and lens of
a box, removable from the camera for containing sensitized plates or negatives,
adapted to operate with such camera and provided with a sliding bottom, which
serves as a cover to the box when removed from the camera, and as a guard to
prevent dropping of the plate when the box is attached to the camera, substantially
as and for purposes as herein before described.
Second. In photographic cameras, the combination with the plate carrier and
lens of a box removable from the camera for containing sensitized plates, and pro-
vided with screwsprings, latches, or other means of clamping the plates within the
box, or releasing such plate, substantially as stated.
Third. In photographic cameras containing in combination with the plate
carrier and lens, a box for reception of sensitized plates and provided screws, spring
latches, or their equivalents for clamping or releasing such plates, the combination
with such plate box, and plate carrier of cooperative means for enabling the
position of each plate with respect to the carrier to be determined mechanically
from the outside of the camera without visual inspection of the interior.
Fourth. In photographic cameras containing in combination with the plate
carrier or slide and lens a box for reception of sensitized plates, the combination
with such box, and the numerals or other characters, distinguishing each groove of
an index bar connected with the plate carrier, and a zero mark or pointer, or
indicator fixed to the camera, or the equivalent of these parts for determining the
position of the plates in the box with respect to the carrier from the outside of
the camera, without recourse to or inspection of its interior.
Fifth. In photographic cameras, and in combination with the plate carrier and
lens thereof, a box for containing sensitized plates removable from the camera and
provided with a spring latch, or screw, or other clamp to each plate guide, or
receptacle, and with a numeral or other character to each guide or receptacle,
whereby the relative position of each plate with respect to the plate carrier may
be determined from the outside of the camera.
Sixth. In combination with the plate carrier of a photographic camera an index
bar, upon which is represented a series of numerals, or other characters synonymous
with the plate receptacles of the plate box or receiver, whereby the position of each
plate with respect to the carrier is ascertained without visual inspection of such
plate and carrier.
Seventh. In photographic cameras containing in connection with the plate
carrier or slide, and the plate receptacle or box, and index for determining the

page_text: position of the carrier with respect to the several plates in the receptacle, the com-
bination with such carrier and its index of a system of focusing the lens, which
consists in scoring or otherwise distinguishing a particular point upon the index
when the focus is obtained in order that the plate carrier after being disturbed
from this focus may be returned to it without readjustment or inspection of the
carrier and lens.
Eighth. In combination the plate box or receptacle containing numerals or other
characters, to distinguish its several plate guides and the plate carrier containing
an index corresponding to such guides and numerals, substantially as and for
purposes herein described,
Ninth. In combination with the plate carrier or slide a bar or plate containing
an index, and operated from the outside of the camera box by a rack and pinion,
or other mechanical device.
Tenth. In combination with a photographic camera, a removable or portable
adjuster corresponding on a reduced scale to the vision outlet or picture boundary
and peep hole of the camera, substantially as and for purposes stated.
Eleventh. In combination with the independent front or extension of the camera
and the camera proper, the swinging brackets pivotted to such camera, and
adapted to hold the extension upright in an advanced position in front of said
camera, substantially as and for purposes herein set forth and described.
Twelfth. The plate carrier or slide as adapted to slide to and fro of the camera
box and with respect to the lens, substantially as and for purposes set forth.
Thirteenth. The opening a³ and glove c² or its equivalent in combination with
the camera case and plate box, substantially as and for purposes set forth.
In witness whereof, I, the said Thomas Henry Blair, have hereunto set my
band and seal, this Thirteenth day of January, One thousand eight
hundred and eighty.
THOMAS HENRY BLAIR. (L.S.)