Improvements in the Manufacture of Lithographic Stones.
Year: 1897

page_text: Date of Application, 19th Jan., 1897
Complete Specification Left. 31st Mar., 1897-Accepted, 15th May, 1897
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Lithographic Stones.
I, GEORGE GATTON MELHUISH HARDINGHAM, of 191, Fleet Street, in the
City of London, Civil Engineer and Chartered Patent Agent, do hereby declare
the nature of this invention (a communication to me from James McLoughlin,
of 894, Broadway, in the City, County and State of New York, United States of
America, Publisher,) to be as follows:-
This invention relates to stones for use in lithographic printing; the object being
to produce, at a comparatively moderate cost, a stone having an extended continuous
printing surface.
It well known by those familiar with the art of lithography and with the trade
in lithographic stones, that the quarries yield stones only of a limited surface area,
and that the cost of lithographic stones, of equal quality, increases in an exaggerated
proportion to their size or superficial area, and hence what are classed as large
stones are relatively very costly. Moreover, the maximum size is limited as before
stated.
According to this invention, stones of any size capable of being printed from are
produced by building them up of small stones, which are inexpensive; the mode of
procedure being as follows:-
The smaller stones are first carefully planed and accurately jointed and fitted
together, and are then cemented on a continuous base of some stone which has the:
necessary strength, and which possesses qualities, as regards expansion and
contraction, similar to those pertaining to lithographic stone. Slate is a good
base-stone, as it has strength to resist great transverse strains, it can be obtained'
of large dimensions, is comparatively inexpensive and has substantially the same
qualities, under change of temperature, as lithographic stone. Any good cement.
may be used, that employed for mending broken china serving very well.
Thin or worn small stones may be used if desired, and when small stones are,
jointed, mounted and cemented as described the joints do not show in printing and.
design may extend over the entire surface of the stone which may be of almost
unlimited superficial area.
a
Where a stone is to be built up having joints which intersect, it is preferable to
mount the stones, having the joints extending in one direction on separate backing
stones, then plane up the edges of these to form the cross joint, and then mount
these backed sections on a continuous backing common to all. Such a construction
gives two plies or thicknesses of backing.
If a very large backing stone is required it may be built up of smaller, jointed
stones, in two plies with broken joints.
1907

page_text: Improvements in the Manufacture of Lithographic Stones.
I, GEORGE GATTON MELHUISH HARDINGHAM, of 191, Fleet Street, in the
City of London, Civil Engineer and Chartered Patent Agent, do hereby declare
the nature of this invention (a communication to me from James McLoughlin,
of 874, Broadway, in the City, County and State of New York, United States of
America, Publisher,) 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 stones for use in lithographic printing; the object being
to produce, at a comparatively moderate cost, a stone having an extended, continuous
printing surface.
It is well known by those familiar with the art of lithography and with the trade
in lithographic stones, that the quarries yield stones only of a limited surface area,
and that the cost of lithographic stones, of equal quality, increases in an exaggerated
proportion to their size or superficial area, and hence what are classed as large
stones are relatively very costly. Moreover, the maximum size is limited as before
stated.
According to this invention, stones of any size capable of being printed from are
produced by building them up of small stones, which are inexpensive; the mode of
procedure being as follows:-
The smaller lithographic stones are first carefully planed and their edges prepared
so that they are perfectly true, smooth and square and they are then placed together
edge to edge, making a joint so perfect and accurate that it will not show in
printing.
The stones so prepared and fitted are then secured immovably in position, so that
they will not shift with relation to each other and so that the joint will not open.
While this may be accomplished in various ways, it is found that the most practical
and satisfactory way is to unite the edges of the several stones forming the com-
posite stone by cement, and then to mount the stones so united on a backing or slab
of slate to which they are also cemented. The slate base or backing ties the several
lithographic stones together and thus a large composite stone is formed, and, as the
slate has substantially the same coefficient of expansion as the lithographic stone,
the joints are not liable to open when the composite stone is subjected to changes
of temperature. The slate backing also adds strength to the structure, the whole
forming an exceedingly strong and practically integral stone.
In the accompanying drawings, which illustrate the method of carrying out the
invention,
Fig. 1 is a face view of an oblong lithographic stone constructed according to
this invention from three smaller stones; Fig. 2 being a corresponding longitudinal
section.
Fig. 3 is a view similar to Fig. 1 showing a stone built up of four smaller litho
graphic stones; Fig. 4 being a corresponding longitudinal section taken on the
line in Fig. 3.
Fig. 5 is a view in section illustrating a composite stone having a backing formed
of two pieces.
Fig. 6 illustrates mechanical means for binding the stones together so that they
will not shift at the joints.
Referring particularly to Figs. 1 and 2, a a represent several sections of litho-
graphic stone, fitted together edgewise along the lines x, b (Fig. 2) representing the
slate base upon which the sections a a are mounted.
The stone-sections a a are dressed on both faces, their meeting edges being so
carefully dressed that when fitted together the joints will not "print"; that is,
$

page_text: vill not be visible in prints made from the composite stone. The stones or sections
re then, preferably, placed on a carefully dressed slab or base b and cemented
irmly thereto. They may also be cemented to each other, though this may not.
Preferably, also, the printing face of the composite
be necessary in all cases.
stone will be carefully finished after the sections are mounted on th backing-slab.
or case.
It will be obvious that any number-two or more-of the smaller lithographic:
stones may be thus combined to form a larger composite stone.
When the above described mode of mounting the stones is employed, the backing
used should have substantially the same characteristics as regards expansion and
contraction as lithographic stones and have a sufficient strength, and slate is found
to be a satisfactory material for the purpose.
It is preferred to cement the stones together at the joint or joints and to employ
for that purpose the kind of cement used by lithographers for backing worn stones
with slate; this cement will resist the action of the acid used for etching on the
stones to about the same extent as the stone itself. Such cement is primarily in a
liquid condition, and when it is to be used at the joints between the stones it is
better to strain it so as to remove all coarse particles therefrom, as this insures the
edges of the stones being brought snugly together at all points. Where the
cement is more readily acted on by the acid than the stone, it is apt, in the course
of time, to be eaten away and to allow the acid to penetrate the joint and
injure it.
Figs. 3 and 4 illustrate the preferred mode of construction where cross-joints are
It is somewhat difficult to dress up the
required in making the composite stone.
two adjacent edges of a lithographic stone so as to preserve a perfect right angle
To obviate this difficulty, the stones a* a* are
at the junction of the four stones.
mounted on a backing b× (Fig. 4), and the stones a¹ a' on a backing 6. These two..
built up sections (viz., backing and stones) are then carefully dressed at their
meeting edges to form the cross-joint y, and are then mounted on an auxiliary
backing 6, as clearly shown.
It is not absolutely essential that the backing should be in one piece, although it.
will be ordinarily and preferably of this character. Fig. 5 shows a composite
stone in which the two pieces of lithographic stone of different sizes are mounted
on a backing made up of two pieces, the larger piece of the latter being arranged
to overlap or cover the joint between the lithographic stones.
Fig. 6 shows a mode of clamping and binding several stones together by means.
of surrounding bands c united by bolts d.
I would observe that in this specification and in the claims appended hereto, the
kind of joint produced is defined as a joint that will not show up in printing..
By this expression it is meant that a plurality of stones are so united that a
composite stone is produced which may have placed upon it, by means of transfer
or by any other of the ways known in lithography, a design with the lines crossing
the joint, and when a print is taken from the stone the lines of the design will be
substantially unbroken; that is to say, the print will have the same characteristics
as if it had been taken from an integral stone as heretofore practised.
While lithographic stones can be so united according to this invention that the
lines of junction will not show in printing the most delicate kinds of work, such, for
instance, as fine line tints and delicate stipple work, it is not always necessary
to make so close a joint for printing all kinds of work, as, for instance, the coarser
0 kinds of color work, or work in which a number of colors are to be superposed.
The phrase hereinafter used in the claims to define the joint between the
stones, viz., such a joint as will not show up in printing, is therefore to be understood
in a relative sense, as the joints made may vary in accordance with the kind of
printing to be performed by the composite stone.
A stone produced according to this invention also possesses the advantage that
the joints or points where the smaller stones are united will not be disclosed in use

page_text: to the same extent that the veins, which ordinarily appear in natural stones of.
larger dimensions are disclosed in the use and manipulation of such larger stones.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I claim':-
1. A composite lithographic stone, consisting of two or more lithographic stones
so fitted together at their meeting edges that the joint will not show up in printing
and suitable means for holding the said stones with their edges in such contact,
whereby an increased and a substantially continuous printing surface is secured.
2. A composite lithographic stone, consisting of two or more lithographic stones
so fitted together at their meeting edges that the joint will not show up in printing,
and a slate backing on which said stones are secured, said backing serving to hold
the stones with their edges in such contact, whereby an increased and a substantially
continuous printing surface is secured.
3. A composite lithographic stone, consisting of two or more lithographic stones
so fitted and cemented together at their meeting edges that the joint will not show
up in printing, and suitable means for holding the said stones with their edges in
such contact, whereby an increased and a substantially continuous printing surface
is secured.
4. A composite lithographic stone consisting of a plurality of minor composite
lithographic stones, each with a backing slab, the said minor composite stones being
so fitted and cemented together at their meeting edges that the joints will not show
up in printing, and an auxiliary backing on which said minor composite stones are
mounted and cemented.
1
5. A composite lithographic stone, consisting of two or more lithographic stones
so fitted together at their meeting edges that the joint will not show up in printing,
and a backing on which said stones are secured, the stones being cemented together
at said meeting edges by a cement which will resist the etching acid to substantially
the same extent as the lithographic stone.
Doted this 31st day of March 1897