A NEW (OR IMPROVED) MATERIAL OR SUBSTANCE TO BE USED FOR VARNISHING OR PROTECTING AND OTHER LIK THE SURFACES OF LITHOGRAPHS, PHOTO-LITHOGRAPHS, PRINTED SURFACES
Year: 1868

page_text: LETTERS PATENT to Frederic William Hart, of 8, Kingsland Green,
London, in the County of Middlesex, Photographic and Experi-
mental Chemist, for the Invention of "A NEW (OR IMPROVED)
MATERIAL OR SUBSTANCE TO BE USED FOR VARNISHING OR PROTECTING
AND OTHER LIK
THE SURFACES OF LITHOGRAPHS, PHOTO-LITHOGRAPHS,
PRINTED SURFACES."
Sealed the 9th April 1869, and dated the 10th October 1868.
PROVISIONAL SPECIFICATION left by the said Frederic William
Hart at the Office of the Commissioners of Patents, with his
Petition, on the 10th October 1868.
I, FREDERIC WILLIAM HART, of 8, Kingsland Green, London, in
the County of Middlesex, Photographic and Experimental Chemist, do
hereby declare the nature of the said Invention for "A NEW (OR
IMPROVED) MATERIAL OR SUBSTANCE TO BE USED FOR VARNISHING OR PROTECTING
THE SURFACES OF LITHOGRAPHS, PHOTO-LITHOGRAPHS, AND OTHER LIKE PRINTED
SURFACES," to be as follows:-
Hitherto lithographs, photo-lithographs, prints, placards, plans, maps,
and printed surfaces of a like nature have been varnished or protected

page_text: ..
by spirit varnishes or gelatine. I now propose to apply a coating of
albumen suitably prepared to produce an even surface by floating the
prints thereon and afterwards rendering the same insoluble, this having
been discovered by me to be more practicable and cheaper than other
processes previously known (producing at the same time a depth and
tone to artistic subjects). For instance, in the application of spirit
varnishes the paper on which the prints are produced must be first
rendered specially non-absorbent to the spirit, and then the application
of a spiritous solution is prejudicial to the health of the operators, and
likewise dangerous to property owing to its inflammable nature. Again,
in the application of gelatine a surface of metal or glass is first coated
and then transferred to the prints; in this state it is subject to injury
by moisture, and owing to the time spent on the several operations in
each of these known processes the expense is great in comparison to my
process.
I carrying my process into effect I require the prints to be on an
ordinarily well-sized hard paper; then I prepare the whites of eggs or
albumen by breaking up the mass into an uniform liquid, as is usual
with photographic albumenized paper preparers, and also coat the
surfaces after their manner; but for this new process I consider it
advisable to introduce into the albumen matter of a deliquescent nature
in such proportion as to prevent the compound on the prints becoming
thoroughly desiccated (as in this state it is more conveniently rendered
insoluble). The prints having become dry, in the ordinary acceptation of
the word, I proceed to render the surface coating insoluble to ordinary
moisture by means of steam or boiling water.
Other methods, by
chemical solutions and hygroscopic gases possessing the property of
rendering albumen insoluble, could be employed for this purpose, but I
prefer the first-named as being cheapest.
I have now given an outline of the method of carrying my improve-
ments into effect; I will observe in conclusion that what I consider to be
novel is the application of albumen, the same being rendered insoluble
on the prints, as a protecting varnish for lithographs, photo-lithographs,
prints, placards, plans, maps, and like printed surfaces.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Frederic William Hart in the Great Seal Patent
Office on the 9th April 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERIC
WILLIAM HART, of 8, Kingsland Green, London, in the County of
Middlesex, Photographic and Experimental Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of October, in the year
of our Lord One thousand eight hundred and sixty-eight, in the
thirty-second year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Frederic William Hart,
Her special licence that I, the said Frederic William Hart, my
executors, administrators, and assigns, or such others as I, the said
Frederic William Hart, 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 "A NEW (OR IMPROVED) MATERIAL OR SUBSTANCE
TO BE USED FOR VARNISHING OR PROTECTING THE SURFACES OF LITHOGRAPHS,
PHOTO-LITHOGRAPHS, AND OTHER LIKE PRINTED SURFACES," upon the condition.
(amongst others) that I, the said Frederic William Hart, 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.
NOW KNOW YE, that I, the said Frederic William Hart, do hereby
declare the nature of my said Invention, and in what manner the same.
is to be performed, to be particularly described and ascertained in and
by the following statement, that is to say :-
This Invention consists in protecting the surfaces of lithographs,
photo-lithographic prints, placards, plans, maps, and printed surfaces of
a like nature in an economical and effectual manner by means of a
coating of albumen applied thereto. Hitherto such surfaces when
desirable have been varnished or protected by spirit varnishes or gelatine,

page_text: but such processes have been subject to several objections. For instance,
in the application of spirit varnishes it is necessary that the paper on
which the prints or designs are produced or impressed should first be
especially non-absorbent to the spirit, and in addition to this the appli-
cation of a spirituous solution or fluid is prejudicial to the health of the
operators, and is likewise dangerous to property owing to its inflammable
nature. Again, in the application of gelatine a surface of metal or glass
is first coated therewith, and the gelatine is then transferred to the
surface to be coated; in this state it is subject to injury by moisture,
and in order to render it permanent must be subjected to chemical
treatment. In both the processes above referred to much time is
occupied, and considerable expense necessarily incurred.
In carrying the present Invention into effect I prefer that the prints
or designs should be on a well-sized hard paper, but when this is not
the case, and the paper is unsized or insufficiently sized, I lay the prints
or designs down on a level surface and sponge both sides thereof with a
warm solution of starch or other sizing material, and then hang them up
to dry; if calendered or rolled after this treatment the paper is then
in the condition preferred to be used. I then prepare a sufficient
quantity of albumen by taking the whites of eggs and breaking up the
mass into an uniform liquid by a beating machine or whisk, as is well
known to persons conversant with the preparation of photographic
albumenized paper; I then coat the printed surface of the paper (the
same having been previously dried) with the albumen thus prepared.
It is desirable to introduce into the albumen during the operation of
breaking or whisking matter of a deliquescent nature, such as chloride
of calcium or nitrate of ammonium, and I find that about one per cent.
of such substance is sufficient for the purpose of preventing the albumen
on the paper becoming thoroughly desiccated, as in this state it is
conveniently rendered insoluble. The paper having become dry, in the
ordinary sense of the term, I proceed to render the surface coating
insoluble (in the same sense as varnishes are insoluble) by means of
steam or boiling water. The like result may be obtained by the use of
well-known chemical solutions and hygroscopic gases possessing the
property of rendering albumen insoluble, but I prefer the use of steam
as being cheaper.
The following is a convenient mode of carrying out this portion of
the process :-The coated sheets of paper are suspended from rods or

page_text: cords in a steam chest properly protected to avoid loss of heat by
radiation. A small amount of aqueous vapour is allowed to pass from
the steam generator or boiler through the steam chest; and when the
latter is filled the steam is turned on, and the temperature raised to at
least from 170° to 190° Fahrenheit as rapidly as possible. The sheets of
paper with their surfaces thus protected are then removed and at once
piled face downwards, the result of the treatment above described being
that the prints or designs are covered with a most efficient protective
coating, whilst the prints or designs have a depth and tone imparted
to them which has been unattainable by the methods hitherto adopted
from the fact that the black or deep shadows have a greater amount of
surface given them than the high lights.
Having thus declared and ascertained the nature of my said Inven-
tion, and the manner in which it is to be performed, I would observe
in conclusion that what I consider novel and original, and therefore
claim as constituting the Invention secured to me by the said herein-
before in part recited Letters Patent is, the application of albumen
to the surfaces of lithographs, photo-lithographs, and like printed
surfaces, as and for the purposes herein-before described and set
forth.
In witness whereof, I, the said Frederic William Hart, have
hereunto set my hand and seal, this Ninth day of April, in
the year of our Lord One thousand eight hundred and sixty-
nine.
Witness,
E. P. H. VAUGHAN,
54, Chancery Lane.
F. W. HART. (L.S.)