IMPROVEMENTS IN THE PRODUC- TION OF PRINTING PLATES OR BLOCKS BY PHOTOGRAPHIC MEANS
Year: 1883

page_text: LETTERS PATENT to John Rudolph Meihe, of N° 2, Laurence Pountney Hill,
in the city of London, for an Invention of IMPROVEMENTS IN THE PRODUC-
TION OF PRINTING PLATES OR BLOCKS BY PHOTOGRAPHIC MEANS communi-
cated to him from abroad by Julius Allgeyer and Carl Bolhoevener, persons
resident at Munich in the kingdom of Bavaria
PROVISIONAL SPECIFICATION left by the said John Rudolph Meihe at the
Office of the Commissioners of Patents on the 19th February 1883.
JOHN RUDOLPH MEIнE, of Nº. 2, Laurence Pountney Hill, in the City of
London, "IMPROVEMENTS IN THE PRODUCTION OF PRINTING PLATES OR BLOCKS
BY PHOTOGRAPHIC MEANS," a communication to me from abroad by Julius
Allgeyer and Carl Bolhoevener, persons resident at Munich in the Kingdom of
Bavaria,
This invention has for its object to produce by photographic means blocks or
types which may be used in printing presses simultaneously with letter type.
For this purpose a heliotype-plate prepered in the usual manner, except that
some chloride of calcium (preferably 1 part to 5 parts of gelatine) or some other
substance capable of producing "grain" has been added to the gelatine,―is exposed
under a dia-positive and rolled over with "ink."
Subsequently some graphite powder or other suitable coating is applied to the
surface, or an impression is made upon a gelatine-foil, which may also be covered
with graphite or other suitable coating. In both cases a "grained" negative is
produced, of which one is right-handed and the other left-handed.
Under one of these grained negatives a film of bichromate and glue is exposed to
the light, which film may be composed as hereinafter described. The back of this
glue-film, after due exposure, is then fastened to a wood block to the exact height
of the letter-type to be used with it.
Those parts of the picture which have not been acted upon by the light are now
removed mechanically by friction with moderate damping, whereby the necessary

page_text: relief is produced, which may either be used in the printing press in combination
with letter type, or for the production of electro-type in the same manner as ordinary
engraved wood-blocks.
The exposure of such a film to the light is equally successful with a negative
representing line-engraving.
The film destined to receive the picture and to serve as a printing surface is
prepared in the following manner.
One kilo of glue is soaked in one liter of water for several hours, then dissolved
by adding 30 grammes of bichromate of potash and 12 grammes of glycerine, and
placing the vessel containing the mixture in a warm water bath.
A suitable quantity of the liquid is then poured out on glass-plates which have
been previously coated with a solution of ox-gall. The layer or film of glue thus
deposited is then allowed to dry in a dark place.
When thoroughly dry, it is scraped perfectly even with a suitable instrument,
then taken off from the glass-plate and exposed under the negative in the manner
already described, and so as to expose that side of it which has adhered to the
glass,

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Rudolph Meihe in the Great Seal Patent Office on the
18th August 1883.
JOHN RUDOLPH MEINE, of No. 2 Laurence Pountney Hill, in the City of
London "IMPROVEMENTS IN THE PRODUCTION OF PRINTING PLATES OR BLOCKS
BY PHOTOGRAPHIC MEANS " a communication to me from abroad by Julius
Allgeyer and Carl Bolhoevener, persons resident at Munich in the Kingdom of
Bavaria
This invention has for its object to obtain from drawings, woodcuts, photographs
and other pictures, relief plates which give accurate Copies of the originals
employed and which may be used for printing simultaneously with Letter type.
"
"
For this purpose a heliotype (sun print or Lichtdruck) is first produced on a
plate prepared like ordinary heliotype-plates, except that Chloride of Calcium
in the proportion of one part of the chloride to 5 parts of gelatine or any other
substance capable of producing a grain has been added The heliotype-plate
is exposed to light under a diapositive, rolled over with greasy ink and the image
is either immediately strengthened by strewing graphite powder or some other
suitable coating over it, or an impression is made from it on a gelatine foil, which
impression or Copy may also be strengthened in the manner just described. By
either method a "grained "negative is obtained which in one case is right handed
and in the other case left handed.
Under one of these grained negatives a film chiefly composed of bichromate and
glue, and prepared in the manner hereinafter described, is exposed to light. The back
of this film is subsequently fastened on to a wood block to the exact height of the
type to be used with it-Those parts of the picture on the woodblock, which have
not been acted upon by the light are now mechanically removed by friction with
moderate damping, and by this means the required relief is produced which may
be used, in combination with letter type, for printing in the ordinary type printing
press.
From the same relief plate an electro-type may be produced in the same manner
as from ordinary engraved wood blocks.
The exposure of such a sensitive film to light is equally successful with a lined
negative (the image of which is composed of lines like an ordinary wood cut).
The film destined to receive the picture and to serve as a printing surface is
prepared in the following manner-
One kilogramme of Glue (Cologne-glue) is soaked in one litre of water for several
hours then dissolved by adding 30 grammes of bichromate of potash and 12 grammes
of glycerine and placing the vessel containing the mixture in a warm water bath.
A suitable quantity of the mixture is then poured on glass plates (mirror plates)
which have been previously coated with a solution of ox-gall-The film of prepared
glue thus deposited is then allowed to dry in a dark place-When well dried, it is
Scraped perfectly even with an edged instrument, then taken off from the glass
plate, and exposed under a negative in the manner hereinbefore described, care
being taken to expose that side of the film which has adhered to the glass.
Having now described the invention and the manner in which the same is to be
performed, I wish it to be understood that I claim.-
1. The production of grained negatives, a, by the direct use of a heliotype plate
containing chloride of calcium or any other suitable grain producing substance,
which heliotype-plate has been inked in, and the image strengthened by the
addition of graphite-powder or any other suitable coating. b, by the use of an
impression taken on a gelatine foil and strengthened in a similar manner.

page_text: 2. The production of printing blocks by pouring chrome glue over a plane glass
plate previously prepared with a solution of ox-gall, allowing the film to dry
exposing under a grained negative (which may be obtained as indicated in the
preceding claim) or under a lined negative that side of the film which has adhered
to the glass, attaching the other (back) side upon a base-plate and developing the
relief by means of damp friction for the purpose of using such blocks directly in
the type printing press, or for obtaining printing blocks by means of electro plating
in the manner well known.
In Witness whereof I, the said John Rudolph Meihe, have hereunto set my
hand and seal this 18th day of August AD. 1883.
JOHN RUDOLPH MEIHE 10)