AN IMPROVEMENT IN COLOUR PRINTING
Year: 1885

page_text: We, JULIUS GRETH of Bromberg in the Kingdom of Prussia, Artist and
HERMANN DE BARRANCA of 6 St Swithin's Lane in the City of London, Gentleman
do hereby declare the nature of our invention for "AN IMPROVEMENT IN COLOUR
PRINTING" to be as follows:-
Our invention relates to means of printing by one impression a number of
different colours. For this purpose, we prepare in the well known manner, a
mosaic block consisting of the various pigments made up in a suitable medium,
each pigment occupying its proper place in the picture or design that is to be
produced.
This mosaic block is levelled and covered by a porous fabric such as millers silk.
A roller being now passed over it takes up a certain amount of the pigments in
their proper order and the roller thus coated being then passed over a forme pre-
pared for surface printing having the design on it, transfers the pigments to the
forme, each in its proper place and from this forme an impression is taken as in
ordinary printing.
Several mosaic color blocks may be used for one printing forme, and when
colored designs are required in combination with letterpress, a block and its forme
may, be used along with a type forme, and the paper or surface that is to be
printed upon may first have the colors impressed and then the letter press. It is
convenient in all cases to arrange the mosaic color block in proximity to the forme
so that the roller may at once pass from the one to the other. When several
impressions are to be taken either in colors or in colors and letterpress, it is of
advantage to arrange the color-blocks and formes in succession on one table so as to
give continuity in the operation. As the color blocks become thinner, they may be
adjusted to level as in lithographic presses.
ABEL & IMRAY,
Agents for the Applicants.

page_text: "
We, JULIUS GRETH of Bromberg in the Kingdom of Prussia, Artist, and
HERMANN DE BARRANCA of St Swithins Lane in the City of London, Gentleman
do hereby declare the nature of our invention and in what manner the same is
to be performed to be particularly described and ascertained in and by the
following statement:-
Our invention relates to means of printing by one impression a number of
different colours. For this purpose, we prepare a mosaic block consisting of the
various pigments made up in a suitable medium, each pigment occupying its proper
place in the picture or design that is to be produced. The mode of preparing such
a block is known but, as particular care is required in its preparation, in order
that it may be adapted for our process hereinafter described, we will explain what
we have found to be a good method of producing and applying the pigments. We
first prepare a medium or vehicle for the pigments consisting of a mixture of the
following substances in about the proportions by weight as follows:-
:-
Clean mutton fat, 140-Resin 150,-Venetian Turpentine 450-Japan wax 275–
Lard 650-Boiled linseed oil 1400, Strong lithographic varnish 550. This mixture
being melted has added to it by degrees while it is hot 200 parts of decoction of soap
bark which has been concentrated by boiling to a strength of about 4° Beaumé.
A frothy scum is produced and care is to be taken to keep the heat moderate, so
that the material does not boil over. In about an hour, the scum disappears
leaving the liquid clear. It is then strained through a fine cloth and is ready for
mixing with the various pigments. As these themselves vary greatly in consistence,
it is necessary to vary in a corresponding manner the proportions in which they
should be mixed with the medium. For some of the principal colours, we find the
following proportions suitable. Assuming 500 parts by weight of colour in each
case, the quantity of medium should be as follows: for 500 parts of Zinc-white,
650 parts of medium-for Cinnabar, 175-for Ultramarine 600,-for Miloriblue 800,
for black 800 for light chrome yellow 800,-for dark chrome yellow 300,-for
carmine 800 for persian red 320.
In mixing the particular colour with its proper proportion of medium, the medium
is brought to a quite liquid condition by heating and the colour is well stirred into
it, and then the mixture is passed several times through a colour mill, preferably
of the kind having finely grained granite rollers, until the mixture is of quite
uniform and fine consistence. When it cools it is solid but somewhat soft, having
about the consistence of firm butter.
•
For making up the block of pigments we find it convenient to proceed in the
following manner. On a plate prepared to hold the block we part off portions at
the angles or sides by strips of wood, card or the like, and into those parts we pour
the liquid pigment. When it has set, we cut, with a knife, guided to cut vertically,
the portions of pigment to the outlines of the spaces which they have to occupy in
the design. Against the portions so cut we pour in like manner other portions and
cut them in their turn, proceeding thus until the block is completed, each pigment

page_text: occupying its proper position in the design. We then level off the surface of the
block which is now ready for use. A roller being passed over it takes up a certain
amount of the pigments in their proper order, and the roller thus coated, being
then passed over a forme prepared for surface printing having the design on it,
transfers the pigments to the forme, each in its proper place, and from this forme
an impression is taken as in ordinary printing. In thus transferring the colours
from the mosaic block to the forme, it is necessary to avoid excess of colour and to
provide for proper register of the colors on the roller to the design on the forme..
When the mosaic block is too much softened by warmth in the apartment, it should
be covered with fine porous fabric such as millers' silk, so that the roller can take
up only that which oozes through the pores. At ordinary temperatures, however,
this precaution is not necessary, the roller being passed directly over the surface of
the block. It should, however, have a second roller bearing against it to smooth
the coating and take up excess of colour, this second roller being cleared of the
excess taken up by passing waste paper between it and a third roller,
The roller which takes up the pigments and transfers them to the forme may be
of ordinary glue composition, a metal roller being used for smoothing and clearing
it, or the pigments may be taken up by a metal roller and transferred to a glue
roller which transfers them to the forme. In all cases, in order to secure register, the
transfer and clearing rollers should be geared to the frame or table which carries
the mosaic block and also to that which carries the printing forme, and the block
and forme should be as near each other as possible so that the rollers may pass at
once from the one to the other. As the mosaic blocks become thinner they are
adjusted to level as in lithographic presses. Several mosaic blocks may be used for
one printing forme, and when coloured designs are to be produced in combination
with letter press, a mosaic block and its forme may be arranged in the same press
along with the type forme, so that the paper or surface to be printed on may
receive its colouring and its type impression in close succession. Colour printing
in the manner described above may be effected in any kind of press or printing
machine, provided with suitable gearing for register of the mosaic block to the
forme, and it may be applied to paper or fabric or other recipient surface without
requiring any moistening or special preparation.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is:-
The herein described method of effecting colour printing, by preparing a mosaic
block of pigments of suitable consistence, arranged according to the required design,
passing over this block a roller so as to take up a coating of the pigments, passing
the coated roller over a forme so as to colour its prominences, and taking an impres-
sion from the coloured forme.
ABEL & IMRAY,
Agents for the Applicants.