AN IMPROVED METHOD OF OBTAINING IMPRESSIONS ON AN ENLARGED OR DIMINISHED SCALE FROM ENGRAVED PLATES OR OTHER PRINTING SURFACES
Year: 1858

page_text: LETTERS PATENT to Henry George Collins, of Paternoster Row, in the
City of London, for the Invention of "AN IMPROVED METHOD OF OBTAINING
IMPRESSIONS ON AN ENLARGED OR DIMINISHED SCALE FROM ENGRAVED PLATES
OR OTHER PRINTING SURFACES."
Sealed the 1st September 1858, and dated the 5th March 1858.
PROVISIONAL SPECIFICATION left by the said Henry George Collins at
the Office of the Commissioners of Patents, with his Petition, on the
5th March 1858.
I, HENRY GEORGE COLLINS, of Paternoster Row, in the City of London,
do hereby declare the nature of the Invention for "AN IMPROVED METHOD OF
OBTAINING IMPRESSIONS ON AN ENLARGED OR DIMINISHED SCALE FROM ENGRAVED
PLATES OR OTHER PRINTING SURFACES," to be as follows:-
This Invention has for its object an improved method of obtaining impres
sions on an enlarged or diminished scale from engraved plates or other printing
surfaces. When I wish to obtain impressions on an enlarged scale of a design.
on an engraved plate or other printing surface I print from the surface with.
transfer ink an impression on to a sheet of vulcanized india-rubber, which I
then put into a frame and extend equally in all directions, and this result.
I ensure by measuring from time to time the distances between different

page_text: marks made on the sheet when in an unextended state, and I adjust the
tension until I find that these distances have all been increased in the same
ratio. I then transfer from the extended sheet on to a prepared surface of
stone or other material, and from this surface I print the enlarged impressions
in the usual way; when the degree of extension required is greater than can
be obtained at one operation it is only necessary to repeat the process. By
reversing the operation I obtain reduced impressions of the design on the
engraved plate or other printing surface, that is to say, by extending the elastic
sheet equally in all directions by the method before described, and then
printing on to it the transfer impression, which, after the sheet is released, is
put upon the stone or other prepared surface from which the reduced im-
pressions are printed.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry George Collins in the Great Seal Patent Office on the
4th September 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
GEORGE COLLINS, of Paternoster Row, in the City of London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of March, in the year of our Lord One
thousand eight hundred and fifty-eight, in the twenty-first year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Henry George Collins, Her special licence that I, the said Henry George
Collins, my executors, administrators, and assigns, or such others as I, the
said Henry George Collins, my executors, administrators, and assigns, should
at any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "AN IM-
PROVED METHOD OF OBTAINING IMPRESSIONS ON AN ENLARGED OR DIMINISHED SCALE
FROM ENGRAVED PLATES OR OTHER PRINTING SURFACES," upon the condition
(amongst others) that I, the said Henry George Collins, my executors or
administrators, by an instrument in writing under my, or their, or one of their
hands and seals, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed, and cause
the same to be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.

page_text: NOW KNOW YE, that I, the said Henry George Collins, do hereby declare
the nature of the said Invention; and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say :—
This Invention has for its object an improved method of obtaining impres-
sions on an enlarged or diminished scale from engraved plates or other printing
surfaces. When I wish to obtain impressions on an enlarged scale of a design
on an engraved plate or other printing surface, I print from the surface with
transfer ink an impression on to a sheet of vulcanized india-rubber, which I
then put into a frame and extend equally in all directions, and this result
I cusure by measuring from time to time the distances between different
marks made on the sheet when in an unextended state, and I adjust the
tension until I find that these distances have all been increased in the same
ratio. I then transfer from the extended sheet on to a prepared surface of stone
or other material, and from this surface I print the enlarged impressions in
the usual way; when the degree of extension required is greater than can be
obtained at one operation it is only necessary to repeat the process. By
reversing the operation I obtain reduced impressions of the design on the
engraved plate or other printing surface, that is to say, by extending the elastic
shect equally in all directions by the method before described, and then
printing on to it the transfer impressions, which, after the sheet is released, is
put upon the stone or other prepared surface from which the reduced im-
pressions are printed.
.
And in order that my said Invention may be most fully understood and
readily carried into effect, I will proceed to describe minutely the method in
which I prefer to operate. I take a sheet of vulcanized india-rubber of No. 16
guage, or somewhat stouter if the sheet be of large size, say, if it be larger
than 18 inches square, and on one side of this sheet of india-rubber I print, by
means of a plate prepared for the purpose, a number of lines, dividing the
surface up. into squares
of one inch cach, and these are subdivided by other
lincs finer than the first, or otherwise differing from them, so as to mark out
each, square inch into 16 small squares measuring of an inch on each side.
On the edges of the sheet I then punch a number of small holes, say, at
distances of three quarters of an inch apart all round; these holes are
employed in stretching the sheet, as will be presently described. If it be
desired, by means of the sheet thus prepared, to obtain impressions on an
enlarged scale of a design, on an engraved plate or other printing surface, I
proceed at once to apply to the sheet, by means of a brush, a thin coating of
a composition prepared in the following manner: From 1 lb._of_flour_a

page_text: thick paste is made, and to it is added lb. of treacle, 1 oz. of dry starch,
1 lb. of, white lead, and 1 oz. of gelatine; dissolved in a sufficient quantity
of water to reduce the whole composition' to the consistency of cream. After
applying this composition to the sheet it is allowed to remain till it is quite
dry; an impression is then taken in strong transfer ink from the plate or
printing surface on to the coated surface of the india-rubber sheet. This
impression is made as nearly as possible in the centre of the sheet, and there
should be a margin of two or three inches left all round the sheet. The
printing being accomplished, I now place the sheet in a strong rectangular
frame, by preference of metal, and of such a size that the sheet of india-
rubber may, if it is necessary, be stretched in it to four times its natural size.
Through the centre of each of the sides of the rectangular frame a screw
passes, and as the holes through which these screws work are not tapped, the
screws slide freely through the sides of the frame, and they have hooks formed
on their inner ends, which pass over the wires on which the india-rubber is
threaded, as before described. On the stems of the screws, exterior of the
frame, there are nuts, by screwing up which the inner ends of the hooks are
drawn away from each other. The sides of the frame, on each side of each of
the screws already mentioned, are slotted, and eight other screws pass through
these slots, so that in all twelve screws are employed, three on each side, or
if the sheet when unextended is larger than twelve inches square, the number
of screws should be further increased. The screws passing through the slots
hook on to the wires, as do the other screws, and are in the same manner
furnished with nuts. The sheet of india-rubber being thus arranged in the
frame, the nuts are turned, so as to extend it equally in all directions, and in
performing this operation I take care to keep the lines crossed at the centre
of the sheet constantly straight, and I keep the tension of the sheet on these
central lines (which come just opposite the screws in the centre of the
sides) slightly in advance of the tension of the rest of the sheet, until by
measuring I ascertain that they are extended to the required degree; then
by the other screws complete the tension of the sheet, until the distance
between the lines is the same in every part of the sheet, and until a square
applied to the surface shows that all the lines running in one direction are
perpendicular to those in the other direction. I would here remark, that I
do not consider it advisable to extend a design at one operation beyond four
times its original surface. When the sheet is extended, I transfer from it in
the manner well understood and usually employed by lithographers on to
a lithographic stone or other similar surface (zinc, for example, may be
employed), from which the enlarged impressions are printed, as if the design

page_text: had been originally drawn on the stone or other surface. To obtain reduced
impressions of a design on an engraved plate or other printing surface I
proceed in a precisely similar manner, except that I take the impression on to
the india-rubber sheet when it is in an extended state, and transfer from it
on to the stone or other surface when it has regained its natural size.
Having thus described the nature of my Invention, and the manner of
performing the same, I would have it understood that I do not confine myself
to the exact details described, but what I claim is, the taking an impression
from an engraved plate or other printing surface on to a sheet of vulcanized
india-rubber, and then either after stretching such sheet, or allowing it to
contract, as the case may be, transferring from such sheet on to a lithographic
stone or other suitable printing surface, from which a great number of
impressions may be printed.
In witness whereof, I, the said Henry George Collins, have hereunto
set my hand and seal, this Second day of September, in the year
of our Lord One thousand eight hundred and fifty-eight,
Witness,
S. CARPMAEL.
H. G. COLLINS. (L.S.)