Improved Means applicable for use in the Production of "Grain" Blocks for Photo-mechanical Printing.
Year: 1898

page_text: "
PROVISIONAL SPECIFICATION.
Improved Means applicable for use in the Production of "Grain"
Blocks for Photo-mechanical Printing.
I, ERNEST PITMAN, of The Phonetic Institute, Bath, in the County of Somerset,
Shorthand and General Publisher, do hereby declare the nature of this invention
to be as follows:-
This invention relates to an improved method of and means for producing
originals" for use in preparing blocks suitable for printing.
In ordinary "block" printing, it has hitherto been difficult to produce "half-
tone" effects. The object of the present invention is to render such effects easy
of attainment and in an economical manner.
In the production of an "original" according to my improved method, I pre-
pare a mould having an inner face composed of a number of minute pyramids,
same being produced by means of V-shaped parallel grooves arranged in two
series, the one crossing the other at right-angles or thereabouts. With the aid
of this mould, I form a plate composed of a black substance, such as a mixture
of wax with blacklead; the surface of the plate consisting of a number of minute
pyramids corresponding with the inner surface of the mould. The serrated sur-
face of the plate is then served with a coating of a white substance, such as plaster
of Paris, the thickness of the coating being sufficient to entirely fill the V-shaped
grooves.
The serrated surface may also be produced by scoring the face of the plate, or
by means of pressure or with the aid of rolls having serrated surfaces.
Upon the coating becoming set, the plate is ready for the reception of the
design which may be etched or otherwise depicted thereon in pencil or other
material.
By scraping, dissolving, or chemically reducing the coating to a greater or less
depth, according to the nature of the design, the apices of the pyramids become
apparent and impart to the surface so reduced a grey or "half-tone" appearance.
If the scraping process be continued, more of the black substance and less of the
white coating will become visible as the pyramids become more blunted, the result
being a deeper "tone."
It will be readily perceived that the design is produced in a series of minute
spots or specks which are either black or white in colour; but which according
to the severity of the reduction process vary in size and become more or less
separated from each other, thus giving half-tone and deep shadow effects as may
be desired.
The plate with serrated surface may be formed of the white substance and the
coating may be composed of the black substance, in which case the scraping or
reduction process would bring into view the high lights, instead of the shadows.
Having obtained the original as above described, the printing block may be

page_text: prepared therefrom by
usually practised.
means of photography according to any of the metho
For the Applicant,
G. G. M. HARDINGHAM,
Chartered Patent Agent,
191, Fleet Street, London, E.C.
Improved Means applicable for use in the Production of "Grain "
Blocks for Photo-mechanical Printing.
I, ERNEST PITMAN, of The Phonetic Institute, Bath, in the County of Somerset,
Shorthand and General Publisher, 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 an improved method of and means for producing
originals" for use in preparing blocks suitable for printing.
In ordinary "block" printing, it has hitherto been difficult to produce "half-
tone" effects. The object of the present invention is to render such effects easy
of attainment and in an economical manner.
In the production of an original" according to my improved method, I pre-
pare a mould having an inner face composed of a number of minute pyramids,
same being produced by means of V-shaped parallel grooves arranged in two
series, the one crossing the other at right-angles or thereabouts. With the aid
of this mould, I form a plate composed of a black substance, such as a mixture
of wax with black-lead; the surface of the plate consisting of a number of minute
pyramids corresponding with the inner surface of the mould. The serrated sur-
face of the plate is then served with a coating of a white substance, such as plaster
of Paris, the thickness of the coating being sufficient to entirely fill the V-shaped
grooves.
The serrated surface may also be produced by scoring the face of the plate, or
by means of pressure or with the aid of rolls having serrated surfaces.
Upon the coating becoming set, the plate is ready for the reception of the
design which may be etched or otherwise depicted thereon in pencil or other
material.
By scraping, dissolving or otherwise reducing the coating to a greater or less
depth, according to the nature of the design, the apices of the pyramids become
apparent and impart to the surface so reduced a minutely speckled appearance,
amounting to a half-tone" effect. If the reducing process be continued, more
of the black substance and less of the white coating becomes visible as the pyramids
become more blunted, the result being a deeper "tone."
"
It will be readily perceived that the design is produced in a series of minute
black spots or specks on a white ground, these specks varying in size and in dis-
tance apart according to the severity of the reduction process, half-tone and deep
shadow effects being thus obtained.
The plate with serrated surface may be formed of the white substance and the
coating may be composed of the black substance, in which case the scraping or
reduction process' would bring into view the high lights, instead of the shadows.
Having obtained the original as above described, the printing block may be
prepared therefrom by means of photography according to any of the methods
usually practised.

page_text: Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I claim:--
1. The herein described method of producing "grain" blocks, consisting in
forming from suitable black [or white] material a foundation having a surface
composed of a number of minute pyramids or similar prominences, and then serv-
ing the said surface with a coating of suitable white [or black] material, the coating
being subsequently removed to a greater or less depth, according to the depth of
tone" required.
2. A "grain" block adapted for rendering "half-tone" effects and consisting
of a black [or white] foundation formed with a crosswise-scored surface and
coated with a white [or black] covering, capable, together with the apices of the
pyramids or serratures pertaining to the surface of the foundation, of being readily
removed, by scraping or otherwise, to a greater or less depth.
Dated this 20th day of October 1898.
For the Applicant,
G. G. M. HARDINGHAM,
Chartered Patent Agent,
Clun House, Surrey Street, London, W.C.