IMPROVEMENTS IN THE PREPARATION OF PAPER OR OTHER SURFACES FOR THE PROAL SP
Year: 1870

page_text: LETTERS PATENT to John Robert Johnson, of No. 36,
.
Rathbone
Place, in the County of Middlesex, Director of the Auto-type
Printing and Publishing Company, Limited, for the Invention of
** IMPROVEMENTS IN THE PREPARATION OF PAPER OR OTHER SURFACES FOR THE
PROVISIONAL SPECIFICATION left by the said John Robert Johnson
at the Office of the Commissioners of Patents, with his Petition;
on the 22nd January 1870.
I, JOHN ROBERT JOHNSON, of No. 36, Rathbone Place, in the County
of Middlesex, Director of the Auto-type Printing and Publishing Com-
pany, Limited, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE PREPARATION OF PAPER OR OTHER SURFACES FOR
THE PRODUCTION OR MANUFACTURE OF PICTURES BY PHOTOGRAPHY," to be as
follows:-
My Invention consists of certain improvements in the preparation of
the surfaces employed in the production of that class of photographic

page_text: pictures in which the coloring matter is carbon (lampblack) or other
pigment.
1. It has been usual in obtaining such pictures to mix the pigment
ground in water with gelatine, albumen, or gum, or their analogues, and
with sugar and its analogues, and to spread the compound upon paper or
other surface. The sugar is added for the purpose of giving flexibility to
the prepared paper, of increasing its sensitiveness to light, and its solubility
in water, with which it is subsequently treated to reveal or develope the
picture. The paper so prepared is floated or immersed in a solution of
bichromate of potash and when dry is exposed to light under a negative.
The parts acted upon by light then become more or less insoluble in pro-
portion to the intensity of the action, and remain upon the paper con-
stituting the picture after its immersion in warm water while those
unacted upon wash away a
and are removed.
It has been found that the addition of sugar notwithstanding its advan-
tages is attended with very serious drawbacks, the paper prepared with it
is too easily effected by damp or moisture, is so soluble as to run or flow
when immersed in the bichromate bath even at the temperature of
.ordinary summer heat. The solubility of the sugar causes it to dissolve
out and contaminate the bath, and this occuring in different proportions at
different times according to the temperature uniform results cannot be
obtained.
Now the first of my improvements consists in substituting for sugar
a substance or substances which shall give flexibility to the tissue,
be soluble in water, and which shall be insoluble in the sensitizing
solution, that is the solution of the bichromate or its analogue employed,
and the best substances with which I am at present acquainted are the
soluble soaps, the stearates or oleates of the alkalies, and particularly soft
soap, the oleate of potash of potash. These substances while possessing all
the properties of the sugar for this purpose in an enhanced degree are
not only free from the objections to the use of that substance already
referred to, but confer other qualities to the pigment compound which
will be set forth below."
2. It has been usual to employ printers' ink and other pigments
ground in oil for the production of photographic pictures, such pigments
being mixed with bitumen or asphalt and with tallow, soap, or other
fatty bodies, with or without a bichromate, but in some cases the paper
prepared with the pigment compound of this nature after exposure to

page_text: Light is treated with oil of turpentine, naptha, or other solvent of fatty
bodies: The original compound unacted upon by light is dissolved by
this menstruum, while that upon which the light has acted has become,
insoluble and remains behind, forming the picture...
Now I have found that instead of the compound of bitumen and
other bodies above described as the sensitive vehicle or medium for
fixing the printers' ink and other oily pigments I may employ gelatine,
or its congeners, and bichromate of potash or other alkali when the
soluble soaps form a part of the compound as before described. In this
case I have only to substitute, a pigment ground in oil for that ground
in water, the compound spread upon paper or other surface when dry
being exposed to light and treated with warm.
1.water to reveal the picture
as in the first casc. The advantages of this substitution for the bitumen
or such like matter being greatly increased sensitiveness and the
possibility of the use of water instead of inflamable and offensive
volatile oil hitherto employed to reveal or develope the picture.
3. My third improvement consists in replacing the gelatine and its
analogues in the above compounds wholly or in part by certain other
organic compounds having the property of insolubility in warm water;
but of solubility. in some other chemical agent, such as ammonia or
the alkalies or salts, and the best substances, I am at present acquainted
with are the proteine compounds which possess the specified properties,
such as casein, legumine, modified albumen, and their congeners. A
pigment compound so formed and mixed with a bichromate is sensitive
to light, but the picture is not revealed or developed by hot water until
a few drops of ammonia or other alkali possessing the like property has
been added to the water.
-
SPECIFICATION in pursuance of the conditions of the Letters Patent,.
filed by the said John Robert Johnson in the Great Seal Patent.
..Office on the 22nd July 1870.
TO ALL TO WHOM THESE PRESENTS: SHALL COME, I, JOHN
ROBERT, JOHNSON, of No. 36, Rathbone Place, in the County of Middle-
sex, Director of the Autotype Printing and Publishing, Company,
Limited, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-second day of January, in the
144

page_text: year of our Lord One thousand eight hundred, and seventy, in the
thirty-third year of Her reign, did, for Herself, Her. heirs and suc-
cessors, give and grant unto me, the said John Robert Johnson, Her
special licence that I, the said John Robert Johnson, my executors,
administrators, and assigns, or such others as I, the said John Robert
Johnson, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after. 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 Inven-
tion for "IMPROVEMENTS IN THE PREPARATION OF PAPER OR OTHER SURFACES
FOR THE PRODUCTION OR MANUFACTURE OF PICTURES BY PHOTOGRAPHY," upon the
condition (amongst others) that I, the said John Robert Johnson, 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 inme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Robert Johnson, 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 thereof, that is to say :-
My Invention consists of certain improvements in the preparation
of the surfaces employed in the production of that class of photographic
pictures in which the coloring matter is carbon (lampblack) or other
pigment.
1. It has been usual in obtaining such pictures to mix the pigment
ground in water with gelatine, albumen, or gum, or their analogues, and
with sugar and its analogues, and to spread the compound upon paper
or other surface. The sugar is added for the purpose of giving flexibility
'to the prepared paper, of increasing its sensitiveness to light and its
solubility in water, with which it is subsequently treated to reveal or
'develope the picture. The paper so prepared is floated or immersed in a
solution of bichromate of potash, and when dry is exposed to light under
a negative. The parts acted upon by light then become more or less
'insoluble in proportion to the intensity of the action and remain upon

page_text: the paper constituting the picture after its immersion in warm water,
while those unacted upon wash away and are removed.
It has been found that the addition of sugar notwithstanding its
advantages is attended with very serious drawbacks.
The paper
prepared with it is too easily affected by damp or moisture; is so soluble
as to run or flow when immersed in the bichromate bath even at the
temperature of ordinary summer. heat. The solubility of the sugar
causes it to dissolve out and contaminate the bath, and this occurring
in different proportions at different times according to the temperature
uniform results cannot be obtained.
Now the first part of my improvements consists in substituting for
sugar a substance or substances which shall give flexibility to the tissue,
shall be soluble in water, and which shall be insoluble.in. the sensitizing.
solution, that is, the solution of the bichromate or its analogue employed,
and the best substances with which I am at present acquainted are the
soluble soaps, that is to say, the stearates or oleates of the alkalies, and
particularly soft soap, the oleate of potash. These substances while
possessing all the properties of the sugar for this purpose in an enhanced
degree are not only free from the objections to the use of that substance
already referred to, but confer other qualities to the pigment compound
which will be set forth below.
In carrying out my Invention I find that but a very small quantity
of such soap in proportion to the gelatine used is required; for instance,
to make a good pigment composition with which to coat paper, which
after being coated shall have the specified properties, viz., flexibility and
infusibility in the bath at moderate temperatures, I take of gelatine 1 lb.,
water 4 lbs., colouring matter a variable quantity according to its nature
and properties, as will be well understood, but, for example, say, lamp-
.black, 100.grains, soft soap 1 oz.
I dissolve the gelatine in the water,
add the lampblack previously ground to an impalpable state of division,
and then gradually, add the soft soap previously dissolved in 'distilled
water. But these proportions may be greatly varied, for instance, one
per cent. of soap has a material effect in diminishing the brittleness of
'the gelatine, while 10 or 15 per cent. may be added without serious
detriment to the resulting compound. I prefer, however, to use tlie
soap in the proportions stated. If it be desired to make the tissue
sensitive at once to the above quantities of the pigment compound
add of the double chromate of potash and ammonia 1½ oz. dissolved. in

page_text: the smallest quantity of water possible, to which a few drops of liquid
ammonia has been added. The compounds so formed, insensitive
and-sensitive respectively, may then be spread upon the paper in the
usual way, as is well understood.
:
.
I claim in the preparation of paper or other surfaces for the production
ör manufacture of pictures by photography the use of a pigment com-
pound formed with gelatine or its congeners and a stearate or oleate of
of an alkali, substantially as described.
ני
2. It has been usual to employ printers' ink and other pigments
ground in oil for the production of photographic pictures, such pigments
being mixed with bitumen or asphalt, and with tallow, soap, and other
fatty bodies with or without a bichromate, but in such cases the paper
prepared with a pigment compound of this nature after exposure to light,
is treated with oil of turpentine, naphtha, or other solvent of fatty bodies.
The original compound unacted upon by light is dissolved by this
menstruum, while that upon which the light has acted has become
insoluble and remains behind, forming the picture.
Now I have found that instead of the compound of bitumen and other
bodies above described as the sensitive vehicle or médium for fixing the
printers' ink and other oily pigments I may employ gelatine or its
congeners and bichromate of potash or other alkali when the soluble
soaps form a part of the compound as before described. In this case I
have only to substitute a pigment ground in oil for that ground in water,
the compound spread upon paper or other surface being exposed when
dry to light and treated with warm water to reveal the picture as in the
first case. The advantages of this substitution for the bitumen or such
like matter are greatly increased sensitiveness, and the possibility of the
use of water instead of the inflammable and offensive volatile oil hitherto
employed to reveal or develope the picture. In carrying out this part of
my Invention I merely substitute for the lampblack ground in water
in the preceding mixture a relative quantity of the same or other
pigment ground in oil, but I regrind such oily pigment with the soft
soap and a little water, and add these gradually to the gelatine as
before.
I claim in the preparation of paper or other surfaces for the pro-
duction or manufacture of pictures by photography the use of a pigment
compound formed of printers" ink or other oily pigment of gelatine or

page_text: its, congeners and of a stearate or oleate of an alkali, substantially as
described
1
.
3. My third improvement consists in replacing the gelatine and..its
analogues, in the above compounds wholly or in part by certain other
organic compounds having the property of insolubility in warm water
but of solubility in some other chemical agent, such as ammonia, or the
alkalies or salts, and the best substances I am at present acquainted with
are the proteine compounds which possess the specified properties, such
as caseine, legumine, modified albumen, and their congeners. A
pigment compound so formed and mixed with a bichromate is sensitive
to light, but the picture is not revealed or developed by hot water until
a few drops of ammonia or other alkali possessing the like property has
been added to the water.
.
In' carrying out this part of my Invention I form a curd of skimmed
milk as in making cheese by precipitating the caseine with rennet or by
an acid; I collect the curd on a filter, and after partially drying it by
pressure I dissolve the caseine or curd in dilute liquor ammonia. This
solution, which should be as thick as the previously described solution of
gelatine in four and a half parts of water, I use instead of a portion of
the gelatine solution, that is to say, I take away part of the gelatine
solution and substitute in lieu thereof an equal portion of the caseine
solution. The quantity so substituted may be greatly varied. Ten per
cent. of the caseine solution so substituted renders the resulting
compound insoluble in water until a certain quantity of ammonia has
been added, and twice or three times that quantity does not prevent a
workable tissue compound being formed. And in making such a
pigment compound I find it best to mix the caseine solution with that
of the soap and add the two together to the gelatine. Soap, however, is
not absolutely necessary, as the caseine itself gives flexibility to the
tissue and thus supersedes the necessity of employing the soap.
I claim in the preparation of paper or other surfaces for the production*
or manufacture of pictures by photography the use of a pigment
compound formed by substituting wholly or partially curd or caseine or
such like organic substance insoluble in warm water but soluble in
alkaline or saline solutions for the gelatine or for a part thereof in the
above pigment compounds.
In all the compounds above referred to I prefer in place of the
ordinary soft soap of commerce to use oleate of potash made by mixing

page_text: the acid and alkali directly, I also use oleate of ammonia, and I find that
all the soaps of commerce possess in a greater or less degree the like
properties.
In witness whereof, I, the said John Robert Johnson, have hereunto
'set my hand and seal, this Twenty-second day of July, in the year 5
of our Lord One thousand eight hundred and seventy.
JOHN ROBT. JOHNSON. (L.S.)