Plates or Surfaces for Photomechanical Printing.
Year: 1884

page_text: Plates or Surfaces for Photomechanical Printing.
I EMANUEL FALK, doing business under the firm of Richard Falk, printer of
38 Behrenstrasse, Berlin W. Prussia, German Empire do hereby declare the nature
of the said invention for IMPROVEMENTS IN THE PRODUCTION OF HALFTONES
OR GRAIN IN PLATES OR SURFACES FOR PHOTOMECHANICAL PRINTING to be as
follows:-
"
"
For producing printing plates for the reproduction or multiplication of works of
art or of natural objects more particularly by means of the printing press lines or
stipple have been used for producing gradations or half tones in photographic
pictures.
Most of the methods consist substantially in producing the gradation of density
during exposure which however necessitates complicated arrangements.
The present process in that respect differs essentially from most of the processes
heretofore known as it permits of the grading of, or production of "grain" in, the
picture without the employment of complicated apparatus but in a simple manner
by employing transparent lines or stipple in combination with opaque lines or
stipple, According to this process the negative possessing half tones has lines
or dots drawn in it mechanically, say by a rose engine so that the negative
becomes transparent at these parts or a picture having half tones in which dark
lines or dots are produced mechanically, (say by printing) is used for making the
negative which then similarly shows transparent lines or dots. After this corre-
sponding or similar opaque lines of different direction; or dots are directly and by
mechanical means produced on the negative having the transparent lines or dots
(say by printing or dusting on) or a separate transparent pellicle is, used which'
contains the, opaque lines or dots and is so placed on the negative that the opaque
lines in the pellicle suitably cross the transparent lines of the negative. From the
negative thus fitted or prepared a print is taken by any of the known methods,
producing a copy capable of being printed, etched or electroplated and the copy may
be taken as required on paper, stone, metal or glass and be used for producing
plates or printing surfaces for typographic lithographic or copperplate printing.
It may be mentioned that the "dots" herein above referred to may have
different shapes say as those properly known as "stipple."
Dated th: 10tL
Danmhan 100d

page_text: Improvements in the Production of Halftones or
"
Grain in
Plates or Surfaces for Photomechanical Printing.
I EMANUEL FALK, doing business under the firm of Richard Falk, Printer of
38 Behrenstrasse, Berlin W, Prussia, German Empire, 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:
--
This Invention relates to improvements in the process for the production by
photography of plates or surfaces for reproducing or multiplying representations of
objects of art or nature.
According to this invention the photographic negative is first of all marked with
transparent lines having one direction, and these are then combined with a system
of non-transparent lines of another direction. This combination of transparent
with non-transparent lines can be produced in various ways.
In the methods hitherto known for producing such printing plates or surfaces for
purposes of reproduction in the printing press, lines or stipple have been used for,
breaking up or "graining" the halftones in the photographic image, such lines
or stipple being inserted between the object and the negative during exposure, or
the exposure is made in the ordinary manner and the photographic image is then
imprinted with the system of lines or dots.
In the first method the "grain" on the picture shows in the form of white lines
crossing one another in the second method the lines are shown black throughout.
All these methods have various defects and a considerable disadvantage is, that
the photographic positive picture. is crossed either only by white lines or only by
dark ones.
In the first kind of picture showing only dark lines they naturally vanish in the
dark parts of the pictures, in the second kind showing only white lines, these
vanish at the high lights of the picture. There is thus no real "halftone" or
gradation in shading over the entire picture.
This principal defect is obviated by the process herein after described as two
systems of lines are used in it whereof one consists of transparent lines, the other
of non-transparent ones.
According to my process the negative with halftones is crossed by mechanical
means, by the aid of a rose engine, with lines or dots so that at those parts the
negative becomes transparent. If the negative is taken from an existing picture
with halftones the transparent lines may be produced in the negative by printing
the dark lines or dots upon the picture, or by "dusting on"; in the same manner
the transparent lines may be produced in the negative by fitting the system of lines
in the camera.
The negative thus crossed with transparent lines can now have similar non
transparent lines produced thereon the direction whereof is different from that of
the transparent lines, these lines may be produced by printing or a separate
transparent pellicle may be used upon or in which non-transparent lines or dots
are produced; when the positive is to be produced this pellicle is so introduced
between the negative and the positive plate that the transparent lines of the
negative suitably cross with the non-transparent lines of the pellicle.

page_text: According to yet another manner the two systems of lines may be so produced
that the picture traversed by black lines or dots is then in another direction
traversed with clear or white lines and dots the negative being taken from that
picture.
These white lines may also be printed upon the picture or be drawn by a rose-
engine. In the latter case that picture has to be photographed at such an angle
that the full light falls into the lines traced as stated so that the edges of the lines
will strongly reflect the light and give the opaque lines in the negative.
By this combination of transparent and non-transparent lines a real gradation of
tone in all the parts of the picture is produced, and entirely white spots are avoided
as well as entirely black ones, and consequently the half tones in the reproduction
will present a very natural appearance and all parts of the picture will be clearly
recognizable.
The effect produced by this method will be greater and more natural, as by
increasing or diminishing the angle under which the two sets of lines cross, the
effect of the light may be excellently adapted to the character of the picture.
By the picture made with transparent and non-transparent lines according to the
method above set forth, a copy suitable for say printing etching or electroplating
may be made on paper, stone, metal or glass and be used in the production of
plates or surfaces for printing in the letterpress, by lithography or in the copper
plate press.
The width of the lines above mentioned may be varied according to the effect to
be produced, or they may be replaced by stipple or by dots of any suitable shape.
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 herein before described method for the production of photomechanical
reproductions showing half tones and serving for the production of printing plates
or surfaces, said method being characterized by marking or tracing upon the
negative transparent lines or dots with which are combined non transparent lines
or dots of different direction.
2. The production of the transparent lines or dots in the negative by mechanical
or by photographic means in combination with the non transparent lines or dots
produced directly by printing or dusting on," or indirectly by a transparent or
non transparent pellicle having such lines or dots.
"
3. The method of producing the white lines on the image or picture having the
black lines, and from which a negative is to be taken, directly by printing or by
the aid of a rose engine.