AN IMPROVED MODE OF COATING PAPER AND OTHER MATERIALS WITH FLUID SUBSTANCES, SOLUTIONS, AND COMPOUNDS FOR PHOTOGRAPHIC AND OTHER PURPOSES
Year: 1867

page_text: LETTERS PATENT to William Robert Lake, of the "International Patent
Office," No. 8, Southampton Buildings, Chancery Lane, in the County of
Middlesex, Consulting Engineer, for the Invention of "AN IMPROVED
MODE OF COATING PAPER AND OTHER MATERIALS WITH FLUID SUBSTANCES,
SOLUTIONS, AND COMPOUNDS FOR PHOTOGRAPHIC AND OTHER PURPOSES."-A
communication from abroad by John Cushing Crosman, of Boston,
Massachusetts, United States of America.
Sealed the 25th June 1867, and dated the 8th March 1867.
PROVISIONAL SPECIFICATION left by the said William Robert Lake
at the Office of the Commissioners of Patents, with his Petition, on the
8th March 1867.
I, WILLIAM ROBERT LAKE, of the "International Patent Office," No. 8,
Southampton Buildings, Chancery Lane, in the County of Middlesex, Con
sulting Engineer, do hereby declare the nature of the said Invention for
"AN IMPROVED MODE OF COATING PAPER AND OTHER MATERIALS WITH FLUID
SUBSTANCES, SOLUTIONS, AND COMPOUNDS FOR PHOTOGRAPHIC AND OTHER PURPOSES,"
a communication, to be as follows:-
The said Invention relates to a process by which sheets of various material,
such as paper, leather, or cloth, are covered or coated with alcoholic, aqueous,.
alkaline, or acid solutions, or with fused resin, oil, varnish, paint, or other
substance applied in the form of a fluid, fluid solution, or matter held in
suspension in fluid, in such a manner that the resulting coating will be smooth

page_text: and of uniform thickness, and when the matter applied contains chemical
salts these will be equally distributed over the surface which is so covered.
The said process consists in first thoroughly moistening or wetting the sheet
of paper or other material which is to be coated; this is preferably effected
by the immersion of the same in suitable fluid, which may be cold or heated
according as one or the other condition is best adapted to produce the desired
effect; then in depositing the wet or damp sheet on a level table, and by
suitable manipulation causing the sheet on its under side to come into contact
with the upper surface of the table, by expressing air and any free fluid from
between the sheet and table, and also where found necessary removing
superfluous fluid from the upper surface of the sheet by application thereunto
of bibulous paper or other suitable absorber or remover; and, finally, in
applying to the upper surface of the sheet when in the condition produced by
the second operation a fluid, or a fluid solution of a material, or a mixture
with fluid of a material with which the said surface is to be coated. When
a considerable quantity or depth of fluid or partially fluid matter is required
to make the desired coating a frame such as paper makers term a deckle is
used, the bottom of which may be faced with rubber; this frame is placed on
the top of the table over the paper, the edges of which the inside of the frame
nearly touches; a suitable quantity of fluid or semi-fluid matter is then
poured on the table, which matter gravitates into uniform depth on the
paper, its flowing off of the same being prevented by the deckle. In some
cases the distribution of the matter may be aided by the use of a brush. In
applying the flowing matter use may be made of a reservoir, which is caused
to traverse over the table and deliver the solution uniformly over the breadth
of the sheet to be coated while so passing, and if desired the matter may be
made to flow into or upon a brush attached to the said reservoir and coming
into contact with the sheet, while the amount delivered may be made to depend
upon a valvular arrangement, and the speed at which the reservoir is moved.
The deckle may be employed with this reservoir, especially if considerable
depth of flowing matter is to be left upon the surface of the sheet. Care
must be taken to have the fluid with which the sheet is saturated one with
which the covering or coating solution or fluid has an affinity. The object of
thoroughly and uniformly wetting, saturating, or damping the sheets before
applying them to the table is to cause them to lie flat thereupon, so that if
the sheet is of uniform thickness there will be no depressions in which the
deposit of coating matter will be thick, or elevations on which it will be
thin.

page_text: When a solution of gelatine mixed with carbon or other pigment is used
for coating paper for photographic purposes the best results are produced with
the temperature of the solution or mixture at from about 100° to 200°
(one hundred to two hundred degrees) Fahrenheit. When a solution of
albumen is used, either alone or in connection with gelatine, with or without
pigments or salts, the temperature should be kept below the point at which
albumen coagulates.. Care should be taken not to remove the coated
sheets from the level table till the coating material has coagulated or set to
such an extent that the removal of the sheets will not be attended with any
disturbance of the coated. surface.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Robert Lake in the Great Seal Patent Office on the
4th September 1867.
TO ALL TO WHOM THESE PRESENTS. SHALL COME, I, WILLIAM
ROBERT LAKE, of the "International Patent Office," No. 8, Southampton
Buildings, Chancery Lane, in the County of Middlesex, Consulting Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters.
Patent, bearing date the Eighth day of March, in the year of our Lord
One thousand eight hundred and sixty-seven, in the thirtieth year of Her
reign, did, for Herself, Her beirs and successors, give and grant unto me,
the said William Robert Lake, Hér special licence that I, the said William
Robert Lake, my executors, administrators, and assigns, or such others
as I, the said William Robert Lake, 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 IMPROVED MODE OF COATING PAPER AND OTHER MATERIALS WITH FLUID SUB-
STANCES, SOLUTIONS, AND COMPOUNDS FOR PHOTOGRAPHIC AND OTHER PURPOSES,"
upon the condition (amongst others) that I, the said William Robert Lake, 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

page_text: calendar months next and immediately after the date of the said Letters
.Patent.
NOW KNOW YE, that I, the said William Robert Lake, do hereby
declare the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement :-
The said Invention relates to a process by which sheets of various material,
such as paper, leather, or cloth, are covered or coated with alcoholic, aqueous,
alkaline, or acid solutions, or with fused resin, oil, varnish, paint, or other
substance applied in the form of a fluid, fluid solution, or matter held in
suspension in fluid in such a manner that the resulting coating will be smooth
and of uniform thickness, and so that when the matter applied contains
ohemical salts these will be equally distributed over the surface which is so
covered,
The said process consists, first, in thoroughly moistening or wetting the
sheets to be coated, which I do preferably by immersion in suitable fluid, which
may be cold or heated according as one or the other condition is best adapted
to produce the desired effect; then in depositing the wet or damped sheet
on a level table, and by suitable manipulation causing the sheet on its under
side to come into contact with the upper surface of the table by expressing
air and any free fluid from between the sheet and table, and also where found.
necessary removing superfluous fluid from the upper surface of the sheet by
application thereunto of bibulous paper or other suitable absorber or remover ;
and, finally, in applying to the upper surface of the sheet when in the condition
produced by the second operation a fluid, or a fluid solution of a material, or a
mixture with fluid of a material with which the said surface is to be coated.
In practice the level table top should be made of substances not changeable
in form on the application of moisture, and glass, slate, marble, or metal may
be used, though I prefer glass. I prefer to supply to each sheet the material
with which it is to be coated by pouring the same upon the surface near the
centre of the sheet.
In applying the material which upon drying or evaporating forms the
desired coating of the sheet, and when the material is of such a nature that
but a small quantity will leave or deposit the requisite coating, the flowing or
spreading of the material over the sheet may be assisted by the operator by
means of a soft brush or other suitable device in the manner of water-color
artists when laying broad washes of flat tints, but when a considerable
quantity or depth of fluid or partially fluid matter is required to make the

page_text: desired coating I make use of such a frame as paper makers term a "deckle,"
the bottom of which may be faced with rubber. This frame is placed on the
top of the table over the paper, the edges of which the inside of the said
frame nearly touches; I then pour on the paper a suitable quantity of fluid
or semi-fluid matter which gravitates into uniform depth on the paper, it
being prevented from flowing off from the paper by the "deckle."
some cases the distribution of the matter may be aided by the operators use
of a brush.
In
In applying the flowing matter use may be made of a reservoir which is
caused to travel over the table and deliver the solution uniformly over the
breadth of the sheet while so passing, and if desired the matter may be made
to flow into or upon a brush attached to said reservoir coming into contact
with the sheet, while the amount delivered may be made to depend upon a
suitable valvular arrangement and the speed at which the reservoir is moved.
The "deckle" may be employed with this reservoir, especially if considerable
depth of flowing matter is to be left upon the surface of the sheet. While
this process was devised by me with reference to the preparation of paper for
use by photographers I do not by any means consider it as limited to such
use, as sheets of material may be coated in the manner described with
alcoholic, aqueous, alkaline, or acid solutions, or with fused resins, oils,
varnishes, or paints; but care must be taken to have the fluid with which the
sheet is saturated one with which the covering or coating solution or fluid
has an affinity. The object of thoroughly and uniformly wetting, saturating,
or damping the sheets before applying them to the table is to cause them to
lie flat thereupon, so that if the sheet is of uniform thickness there will be
no depressions in which the deposit of ccating matter will be thick, or
elevations on which it will be thin.
As one of the prominent objects for which my process will be used is the
preparation of paper for employment in photography it may be well to briefly
notice all the processes known for coating such papers with gelatine or albu-
men. Paper has been floated on the surface of solutions of gelatine or albumen
and then hung up to dry; this makes the coating thin at one end of the sheet
and thick at the other. It has been drawn over the surface of said solutions
and then hung up to dry but with the results just named. It has been floated,
as before mentioned,. and then placed with the coated side uppermost upon a
flat disc which an operator dexteriously turns and tips in such a manner as to
make the coating approximate to a uniform thickness. It has been made
into a belt arranged to pass over drums so that the lower side of the paper

page_text: would touch lightly the surface of the solution. Another method has been to
first rub over a glass plate ox gall or a mixture of nitric acid and alcohol, and
then to pour the coating solution upon the plate, and before said solution.
became dry the paper to be coated was gently pressed thereupon, and when.
dry or nearly so the paper with the coating adhering thereunto was removed
from the plate; but each of such processes has been attended with serious.
difficulties and objections, for it is extremely difficult, if not impossible, by
either of them to cover paper or other sheets with a coating of uniformn
thickness and if the coating used for photographic purposes is not of uniform
thickness the tone of pictures taken thereupon cannot be uniform throughout.
In the process just described wherein the finished face of coated paper is made
directly in contact with a plate of glass it will be evident that if there is
matter in the coating material which will precipitate or gravitate it will be
found at the finished surface which will be deteriorated thereby; but in my
process any matter in the coating material which settles gravitates away from
the finished surface greatly to its improvement. In my improved process by
thoroughly wetting or saturating the paper and then laying it as described on
a level table the upper surface of the paper will necessarily be level, and the
coating fluid poured thereupon will necessarily distribute itself by gravity and
capillary attraction uniformly in thickness over the surface.
When a solution of gelatine mixed with carbon or other pigment is used
for coating paper for photographic purposes the best results are produced with
the solution or mixture at a temperature varying from about 100° to 200°
Fahrenheit. When a solution of albumen is used either alone or in connection
with gelatine, with or without pigments or salts, the temperature should be
kept below the point at which albumen coagulates. Care should be taken
not to remove the coated sheets from the level table till the coating material
has coagulated or set to such an extent that the removal of the sheets will not
be attended with any disturbance of the coated surface. The time required
for the setting or coagulating of the coating of course varies with the
material and attendant atmospheric influences. When the sheets are in a
condition to be moved I prefer to place them separately on other level shelves
or tables, there to remain till they become sufficiently dry or bardened to be
piled one upon another without danger of sticking together. As the sheets
are apt to stick a little at their edges to the level table on which they receive
their coating I make use of a spatula or knife to overcome their adhesion and
by this care prevent tearing the paper.
Having thus fully described the said Invention as communicated to me by

page_text: my foreign correspondent, and shown how the same may be conveniently and
advantageously carried into practice, I claim the herein described process for
coating sheets of paper or other material, substantially as set forth.
In witness whereof, I, the said William Robert Lake, have hereunto set
my band and seal, this Fourth day of September, in the year of
our Lord One thousand eight hundred and sixty-seven.
Witness,
GEORGE HASELTINE.
WILLIAM ROBERT LAKE. (L.S.)