Improvements in and connected with the Photographic Printing of Drawings.
Year: 1899

page_text: Date of Application, 2nd June, 1899-Accepted, 15th July, 1899
COMPLETE SPECIFICATION.
Improvements in and connected with the Photographic Printing
of Drawings.
I, AUGUST SCHWARZ, of 7, Kleine Schifferstrasse, Frankfort-on-the-Main, in
the Empire of Germany, Manufacturer, 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;-
-
This invention relates to the photo printing of drawings upon sensitized paper
by means of artificial light.
The difficulty attendant upon the use of artificial light for the purpose of the
production of photo prints of large drawings is that the rays do not run parallel
as is the case with sun light, but proceed radially from a point, and in conse-
quence the surface of the sensitized paper or film is not regularly illuminated.
The employment of reflectors to obviate this difficulty is only possible for small
surfaces as the source of light must be as near as possible to the sensitized paper
or film.
Consequently nothing further remains for the production of larger
copies than the arrangement closely together of a great number of lights which
of course has the disadvantage of too great expense.
The present invention consists in the employment of an open shell of any
shape having its interior enamelled a dull white and having its interior approxi-
mately of the same size as the drawing to be copied and the arrangement within
such shell of a number of sources of light close to the interior face of the shell
and the arrangement of the copying frame in front of the open part of the shell.
The interior of the shell is regularly illuminated by means of the lights and
reflects light equally upon all parts of the copying frame.
The accompanying drawings illustrate diagrammatically the manner in which
the invention may be carried into effect.
Figure 1 is a front elevation of a shell such as that hereinbefore described.
Figure 2 is a sectional plan corresponding thereto in which the copying frame is
also shown in section.
The shell a is enamelled or painted dull white within and is constructed with
its respective faces of one sheet of metal, or, as illustrated, it may be constructed
of several metal plates which may be rivetted or otherwise secured together to
form a staunch construction. Lights indicated by crosses are arranged in
proximity to the rear interior face of the shell, and these may be arc lamps,
incandescent electric lamps, or mantles, or acetylene gas flames, or other source
of light. (Figure) is the copying frame in which is mounted a glass plate c
behind which the drawing and sensitized paper or film are held by means of a
felt padded wooden plate f pressed home by means of transverse bars g. The
distance e between the shell and the copying frame prevents the undue heating
of the glass plate cand serves for the purpose of observation. The shell and
copying frame may be mounted one in relation to the other as may be con-
venient

page_text: 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. Means for the photo printing of large drawings by artificial light consisting
of a shell corresponding in size to that of the drawing to be copied, which shell
has its interior a dull white and has a number of intense sources of light arranged
within in such a manner that the interior of the shell is uniformly illuminated
for the purpose and substantially as described.
2. An apparatus for the photo" printing of large drawings substantially as here-
inbefore described.
1000
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and 25, Cross Street, Manchester,
Agents.