Improvements in the Method of Making Negatives in Relief or Sheets of Raised Type, on Pure Tinfoil, by Means of Typewriting Machines, or an Agate Style or other Hard Pointed Pencil.
Year: 1898

page_text: Date of Application, 13th July, 1898-Accepted, 17th Sept., 1898
GON DRIE DICITICATION.
Improvements in the Method of Making Negatives in Relief or
Sheets of Raised Type, on Pure Tinfoil, by Means of Typewriting
Machines, or an Agate Style or other Hard Pointed Pencil.
WILLIAM CORDEAUX, Church Fenton, Leeds, Yorkshire, Barrister-at-Law, 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 improvements in the method of making or producing
negative in relief or sheets of raised type on pure tin foil, more particularly
described hereinafter by means of type writing machines, or by an agate style or
other hard pointed pencil, the metallic sheet being indented so that the shape and
character of the type or written letters, or other delineations stand out in relief
on the reverse side of the metallic sheet, the metal being forced outwards when
struck by the type writing machine, or written upon by the agate style or hard
pencil, so as to appear like a stereo-type block taken from ordinary type in the
usual way.
In order to obtain a perfectly level printing, surface, such as ordinary type, when
set up by compositors affords, it is absolutely necessary and essential that every
letter or type should be impressed or indented on the metallic sheet, by the type
writing machine, of a uniform depth, that is to say, one letter should not be
bolder in relief or more prominent than another.
First, with respect to the making of negatives by means of a typewriter, the
present known method or process consists in placing between the metallic sheet,
and the roller, or other surface upon which the paper would rest (if we were
type writing in the usual way), a sheet of blotting paper, or other soft material,
but it is not considered or known to be essential that the metallic sheet should be
fixed to the backing material in close contact with it, and in such a manner that
the metallic sheet cannot be moved or disturbed during the process of indenting
it. The only known method of attaching the metallic sheet to the backing
material, whatever it may be, is by damping it with water, but it is found by
practice that this is not sufficient to hold the metallic sheet and the backing
material in as close contact as they should be, and the result is that a very
inferior negative is made, some letters being more prominent than others, and
some not distinctly indented.
Before describing the new and improved method of fixing the metallic sheet
to the backing material, which is an essential part of the method of making the
negative, I will now more particularly describe the nature and quality of the
metallic sheet, which I have discovered to be the most suitable kind for the pur-
pose, and the use and application of which I claim as a new invention.
I find by experiments and practice that the most suitable metallic sheet which
can be used for this purpose, is composed of pure tin, the nature and quality of it
being such that ten square feet of it would make about one pound in weight, I

page_text: prefer to use this as it is strong enough to withstand the pressure put upon it,
when printing copies from it, and it is not liable to be cut either by the type writ-
ing machine, or a hard pencil.
Having now particularly described what the nature and quality of the metallic
sheet should be, I will now describe the new and improved method of fixing the
metallic sheet to the backing material, before placing it in the type writing
machine.
First, as regards the nature and quality of the backing material, I find that
blotting paper or other soft paper are not suitable for the purpose, I also find that
india-rubber will not answer, on account of its elasticity, I prefer to use a sheet
of mackintosh, known in the trade as single texture jaconet, or water proof sheet-
ing. I do not limit myself to the use of one particular thickness of mackintosh,
as it may be used slightly thicker or thinner to suit the type of the type writing
machine, that is to say, if the type is sharp and clear, the mackintosh should be
thinner. These sheets of mackintosh can be used again & again, as they do not
get indented as blotting or other paper would.
I will now describe the improved method of fixing the metallic sheet to the
mackintosh backing, before placing it in the type writing machine. It is quite
obvious that water will not do, and if gum or any like adhesive substances were
used, the two sheets could not be separated so easily. The improved method
which I believe to be the best, is to coat or rub the surface of the metallic sheet,
and also the mackintosh, with, ordinary common soap, the soap should be used
without water, or if it has got too dry and hard, it may be slightly damped, all
that is required is to make the sheets sufficiently sticky to hold well together just
as if they were waxed over. Any other similar substance might be used, if it was
of a greasy and slightly sticky nature like common soap.
Having thus coated the two sheets, I place them on a glass plate, and with the
edge of a flat piece of hard wood, I scrape over the surface, pressing them together,
or this can be done in an ordinary press.
Having thus fixed the two sheets, I place them together in a type writing
machine, the ribbon (if any) being first removed, and as all the typewriters are not
constructed alike, it may be necessary to remove or partly remove from their usual
positions, other parts of the machine, which might interfere with or disturb the
metallic sheet. The type writer is then worked in the same way, as when typing
paper. If the type is sharp and clear like a Remington, some letters require less
pressure than others.
The top and bottom edges of the metallic sheet may be folded over the mackin-
tosh backing about a quarter of an inch, but this is not essential, it adds to the
security of the sheets being held together.
I have now described the improved method of making a negative for type
writing work. Negatives can also be made by indenting tin foil, such as already
described, by means of an agate pencil, or hard style, other work, such as maps,
music, drawings can also be done in this way. This process is already known,
and has been worked to a certain extent, but hitherto the best results have not
been obtained. Having made many experiments, I find the most suitable pure
tin foil is, such as I have already herein described, and the improved method
which I now claim as a new invention, consists in using the metallic sheet double,
they are held together by soap, in the same way as the type writing sheets are
held. It is quite possible also to use a single sheet of tin foil, but the type or
raised writing is not so firm and strong as on double sheets, any number of copies
can be printed from these negatives and the metallic sheets can be smoothed out
and used again and again for other work. The double sheets should be separated
and then reversed, so that the parts written upon, when smoothed out, are not in
the same place on each sheet, when fixed together for other work.
The present known method of making a negative by means of an agate style or
hard pencil, is to place the metallic sheet, on a glass plate, and underneath, just

page_text: below the line of writing, a narrow strip of steel, and a similar strip on the top,
this suspends the metallic sheet slightly above the glass, and enables the indenta-
tions to be made, in the same way as if the metallic sheet had been placed on a
soft surface instead of on glass. By using the glass, a better surface on the type
is obtained, as the metallic sheet is forced against the smooth glass by the point
of the pencil. In order to obtain the best results, it is necessary that the point of
the pencil should be perfectly smooth and rounded to a slight extent, the more
sharp the point is, the finer the work, but it is easier to write with a medium
point. It is of great importance that the strip of steel placed underneath the
metallic sheet, should be of an exact gauge or thickness, and I find that the most
suitable is what is known in the trade as best cast cold rolled steel 3/4 inch x 6/1000
inch, hard tempd. and polished. The use and application of this steel I claim as
a new invention and improvement.
The copies can be printed and multiplied on a machine which was the subject
of a Patent, No. 13,676, dated July 16th 1894. It is not necessary further to ex-
plain the process of printing the copies, as the subject and object of this specifica-
tion is to set forth certain improvements, which are essential to the method of
making negatives, whether by a typewriter or by an agate pencil or style.
Having now particularly. described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
1. The use and application of a sheet of pure tin foil, such as herein particularly
described, as and for the purpose stated.
2. The improved method of attaching or fixing the tin foil to mackintosh or
india-rubber sheeting, substantially as and for the purpose set forth.
3. The use and application of common soap for the purposes herein described,
whether the negative be made by a typewriting machine or by an agate style or
hard pencil.
4. The improved method of using double sheets of tin foil substantially in the
manner herein described, when making negatives with an agate pencil or other
hard pointed pencil.
5. The use and application of steel strips of the nature and quality herein parti-
cularly described, and for the purpose set forth.
6. The improved method of making the negatives whether by typewriting or by
ordinary writing with an agate pencil or other style, taken as a whole and substan
tially in the manner and for the purpose set forth and herein described.
Dated this 12th day of July 1898.
WILLIAM CORDEAUX.