Improvements in Apparatus for Photographing Engineering Drawings and the like.
Year: 1891

page_text: Date of Application, 6th June, 1891
Complete Specification Left, 5th Mar., 1892-Accepted, 9th Apr., 1892
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Photographing Engineering
Drawings and the like.
I, WILLIAM PALMER, of 1, Greenvale Terrace, Dumbartou, in the County
of Dumbarton, North Britain, Engineer, do hereby declare the nature of this
invention to be as follows, that is to say:
My said invention has for its object to obtain increased efficiency, convenience,
and economy, in photographing engineering drawings and the like; and it is
applicable for making white-ground, blue-ground, or other analogous prints.
In carrying out my invention I employ for the printing operation a frame having
a glass plate which is curved instead of being of the ordinary flat form, and I
secure the tracing or original and the photographic paper on the convex surface of
the glass plate by means of straps or a cloth which can be highly stretched or
bound over them, the arrangement being such as to allow of the tracing and
paper being made free from creases and applied very closely to the glass. In
general the frame may be placed so that the light will act on the concave side
through the glass; in some cases, however, the photographic paper may be placed
next to the glass and the tracing upon the paper, the light acting through the
tracing, and on the convex side, instead of the concave side.
For developing the print I form it into a roll and attach it to a rod or convenient
holder, and immerse it in the chemical liquid contained in a tall vessel of glass or
other suitable material of a circular or other simple form in horizontal section.
The said vessel is proportioned to contain a quantity of the chemical liquid just
about sufficient for the operation on the print without unnecessary excess.
Where
drawings of various sizes have to be photographed, vessels of suitable sizes may be
provided. With these arrangements a smaller quantity of chemical liquid is
required for each operation than with ordinary apparatus for the same purpose, this
being an important advantage especially for white-ground prints for which the
chemical liquid should always be as fresh as possible.
Dated this Fifth day of June 1891.
EDMUND HUNT,
Applicant's Agent.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Photographing Engineering
Drawings and the like.
I, WILLIAM PALMER, of 1, Greenvale Terrace, Dumbarton, in the County of
Dumbarton, North Britain, Engineer, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement, that is to say :-
My said invention has for its object to obtain increased efficiency, convenience,
and economy, in photographing engineering drawings and the like; and it is
applicable for making white-ground, blue-ground, or other analogous prints.
In carrying out my invention I employ for the printing operation a frame having
a curved glass plate, and on its convex surface I secure the original and the photo-
graphic paper by means of straps or a cloth, which can be tightly stretched over
them in a manner to free them from creases, and apply them very closely to the
glass. The frame is placed so that the light will act on the concave side through
the glass; and to develop the print, it is attached to a convenient holder, and
Price 8d1

page_text: immersed in a chemical liquid contained in a tall vessel of glass or other suitable
material.
And in order that my said invention and the manner of performing the same
may be properly understood, I hereunto append two sheets of explanatory
drawings to be hereinafter referred to, and showing some simple and convenient
examples of my improved photographic apparatus. In these drawings the same
reference letters are used to mark the same or like parts wherever they are
repeated.
Figure, 1, on Sheet, 1, of the drawings is a side elevation, showing one example
of the frame and a suitable carriage to support it. Figure, 2, is a plan and
Figure, 3, a longitudinal section of the frame and glass plate. Figure, 4, on
Sheet, 2, is a side view, showing a second example, of the frame supported by a
pair of light wheels and reversible legs, as in the position for fixing the original and
the photographic paper in the apparatus; and Figure, 5, is a side view showing
the same apparatus in position for permitting the light to act through the glass
plate. Figures, 6, 7, and 17, are horizontal sections and Figures 8, 18, and 20, are
vertical sections of vessels employed for holding the chemical liquid to develop the
print. Figures, 9, 11, 13, and 15, are horizontal sections and Figures, 10, 12, 14
and 16, are side elevations of various forms of holders, to which the print is
attached for immersion in the liquid. Figure, 19, is a plan, and Figure, 21, is a
transverse vertical section, as at right angles to Figure, 20, of a vessel employed to
hold the chemical liquid.
'
As shown in the drawings, I employ for the printing operation a frame, A,
having a glass plate, B, which is curved instead of being of the ordinary flat form,
and I secure the original or tracing, C, and the photographic paper, D, on the
convex surface, E, of the glass plate, by means of a cloth, F, which can be tightly
stretched over them, the arrangement being such as to allow of the tracing and
paper being made free from creases, and applied very closely to the glass. When
printing, the frame, A., is placed so that the light will act on the concave side, G,
through the glass, B. The desired pressure of the original, C, and the photo-
graphic paper, D, against the glass plate, B, is arrived at, hand or lever power
being used, by means of the handle, Fl, and clip, J, both of which are securely
fixed to the cloth, F, and the latter of which is made to engage in notches, K, on
the frame. For large sizes, or where it is desired to increase the pressure against
the glass plate, B, one or more steel bands, and a card or vulcanite sheet may be
used to supplement the action of the cloth.
For developing the print, D, according to one modification I form it into a roll,
and attach it to a rod, or convenient holder, L, and immerse it in the chemical
liquid contained in a tall vessel, M, of glass or other suitable material of a circular
form in horizontal section, as shown in Figures, 6, 7, and 17, or the vessel may be
of some simple form such for example as shown in Figure, 19. In the example of
vessel, M, shown in Figure, 8, the line, R, shows the height of the liquid prior to
the inmersion of the print, D, which is first introduced in a position relative to its
holder, L, as shown in Figure, 6, being afterwards coiled as shown in Figure, 7.
Figures 8 to 21, show various forms of holders, L, and the manner in which the
print, D, is to be fixed to each will be easily understood from the drawings.
Where the holders, L, are made in two portions as shown in Figures, 6, to 16,
the parts are held in their closed positions by rubber rings, S.
The holder, L, where desired, can as shown in Figures, 17 and 18, be made
hollow, and be used as a supply tank for chemical liquid, and by means of the
rod, N, and valve, P, be easily made to replenish the vessel, M, when needful.
The said vessel, M, is proportioned to contain a quantity of the chemical liquid
just about sufficient for the immersion of the print, D, without unnecessary excess,
and the liquid may be drained off when desired by a plug, Q. Where drawings of
various sizes have to be photographed vessels of suitable sizes may be provided.
With these arrangements a smaller quantity of chemical liquid is required for each
operation than with ordinary apparatus for the same purpose, this being an

page_text: important advantage especially for white-ground prints for which the chemical.
liquid should always be as fresh as possible.
Having now particularly described and ascertained the nature of my said.
invention and in what manner the same is to be performed, I declare that what I
claim is :-
1. The arrangement and combination of parts constituting my improved apparatus.
for photographing engineering drawings and the like, substantially as herein before
described and as shown in Figures, 1 to 5, of the accompanying drawings.
2. Apparatus for photographing engineering drawings and the like, comprising a
frame with a curved glass plate arranged to receive the original and the photo-
graphic paper on its convex side and to have its concave side directed towards the
operating light substantially as hereinbefore described.
3. For developing photographic prints of engineering drawings and the like, the
use in combination, of holders to which the prints can be attached in a rolled or
other form, and comparatively tall vessels arranged to receive the holders and
prints in a vertical position and by their relatively limited horizontal area and the
displacing action of the holders causing small quantities of liquid to be sufficient,.
substantially as hereinbefore described.
Dated this Fourth day of March 1892.
EDMUND HUNT,
Applicant's Agent.