Improvements in Photographic Printing.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in Photographic Printing.
I, ANDREW FULLER HARGREAVES, Chemist and Manager, Roslin Gunpowder
Mills, Roslin, Midlothian, N.B., do hereby declare the nature of this invention
to be as follows:-
This invention has for its primary object the production of a photograph,
design, pattern, or picture such for instance as a portrait, landscape, builders or
engineers plan or other representation upon cotton, linen, woollen or other textile
fabric or upon paper.
The designs are fixed upon any of the above mentioned materials by a process
hereinafter described, by the deposition or precipitation of a pigment, lake, or
colouring matter heretofore unknown to the art and science of photographic
printing.
The pictures produced are unchanged by exposure to sun-light,
beautiful in colour, and will stand a boiling soap solution.
are novel and
This invention dispenses with the use of any of the salts of gold, platinum,
silver, or any other precious metal, so much used in photography, and is a
development or extension of the well known ferro-prussiate process.
It has for some considerable time been known that prints of a kind can be
obtained say from an ordinary photographic negative, by the ferro-prussiate pro-
cess and it is now extensively used by builders, and engineers, for obtaining
excellent copies or prints of plans, in which the drawing appears in white lines
on a blue ground.
The process is however but little used by photographers, owing presumably
to a want of intensity and development of details especially in what are termed
half tones and other defects.
I wish it to be distinctly understood in describing my invention that so far
as this ferro-prussiate process itself is concerned I lay no claim whatever, it
being as previously stated well known and long used, but on the contrary my
invention begins after the ferro-prussiate print has been produced and fixed
upon the material, which so far as my experience at present goes I prefer to be
bleached cotton cloth.
In order however that my invention may be the better understood I consider
it necessary that I should briefly describe the general principles of the ferro-
prussiate process.
i
Before however doing so it is necessary to observe that although I herewith
describe only one method of obtaining a photographic blue print, there are several
methods or modifications any one of which I may use.
Two chemical substances, ferric ammonic citrate, and potassic ferri-cyanide,
are each separately dissolved in water in about the following proportions:--
175 grains ferric ammonic citrate in 3 ounces water.
150 grains potassic ferri-cyanide in 3 ounces water.
The above solutions are then mixed

page_text: If this compound solution is brushed over a piece of muslin or paper in a
dark place and then dried also in the dark, it is found to be sensitized, that is
to say when brought in contact with solar light it undergoes a chemical change
and becomes blue.
If a piece of lace, a fern leaf, a drawing on thin paper, or an ordinary photo-
graphic negative, be laid on a piece of this sensitized material, pressed down by
means of a plate of glass, and then exposed to sunlight a representation of the
object will be obtained.
Those parts of the sensitive material to which light has access through the
transparent portion of say the negative will become blue, whilst the opaque parts
of the negative protect the print from the light and the sensitized material
immediately behind therefore remains unchanged.
It is only necessary to wash the drawing in water when the unchanged or
soluble material. is washed out, whilst the changed portion which is blue being
insoluble remains..
As previously stated I make no claim to the above process, but use it for the
purposes of my invention, which, although dependent on having this photo-
graphically produced blue print, as a starting point is a distinctly after process,
and any known method for producing the blue print may be used, so long as
it is photographically produced.
It is of course to be understood that when I refer to the blue being produced
by the solar light I include its equivalent such for instance as an electric-are-
light.
This blue colouring matter is Prussian blue or a modification thereof, and, being
a ferrous or ferric ferro-cyanide is an iron compound.
Now the essence of my invention consists in utilizing the iron contained in
the blue colouring matter as above produced by actinic light, and making it the
medium or base for the formation of another colouring matter, which is more
intense, beautiful, and permanent.
In other words I use the iron in the blue as a mordant, in the same way as
calico printers purposely fix oxide of iron on cotton cloth as a preliminary in
the dyeing of purples, blacks, greys etc.
When cotton cloth on which there has been fixed an oxide of iron is subjected
to certain dyeing materials such as alizarin, logwood, or sumac, purples, blacks,
or greys are produced, the first named material producing a well known coloured
lake, known as madder or alizarin purple, and is one of the most permanent
colouring matters known.
Now I have discovered that the blue colour referred to above-being an iron
compound-acts the same as if oxide of iron alone were fixed on the cloth and it
can therefore be used as a mordant.
For the purposes therefore of my invention I use a photographically produced
blue print on any suitable material-though according to present experience I
prefer cotton cloth.
It is important that the prints should have been well washed in water in
order to eliminate all unchanged chemicals and in order to do this more effectually
I may digest them in a dilute solution of hydrochloric acid and afterwards well
wash in pure water.
The blue prints are then dyed up in a dye bath containing any, or all of
the following dyeing materials added to a considerable volume of water, alizarin
madder, purpurin, logwood, nut galls, sumac or quercitron.
Of the above materials I prefer the first.
They are then
The blue prints are preferably entered into the dye-bath at a temperature of
about 100° F. and the temperature gradually raised in 30 or 40
boiling and agitated during the whole time.
clean water and afterwards treated to a boiling soap solution.
well washed, dried, pressed and if desired starched and mounted
minutes to the
well washed in
They are ther
in any desired
way.

page_text: So long as the spirit of the above is maintained any reasonable modification of
the process is claimed and which may be described in my final specification.
Dated this Twenty-sixth day of November 1898.
Improvements in Photographic Printing.
I, ANDREW FULLER HARGREAVES, Chemist and Manager, Roslin Gunpowder
Mills, Roslin, Midlothian, N.B., 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 has for its primary object the production of a photograph,
design, pattern or picture, upon cotton, linen, paper, or other suitable textile
fabric.
The designs are fixed upon any of the above mentioned materials by a process
hereinafter described, by the deposition or precipitation of a pigment, lake, or
colouring matter heretofore unknown to the art and science of photographic
printing.
The pictures produced are unchanged by exposure to sunlight, are novel and
beautiful in colour, and will stand a boiling soap solution.
This invention dispenses with the use of any of the salts of gold, platinum,
silver, or other precious metals so much used in photography, and is a develop-
ment or extension of the well known ferro-prussiate process.
There are various methods recommended for the successful production of these
ferro-prussiate prints, designs, or pictures, but the one I prefer, owing to its
having given me the best results-is herein after described, but I wish it to be
distinctly understood that I may if desired use any of the known methods for
their production provided that the blue colour which is a characteristic of the
process contains iron as one of its constituents and is produced by the actinic
power of solar light or its equivalent, or otherwise by photographic methods.
Two chemical substances, ferric ammonic citrate, and potassic ferri-cyanide,
are each separately dissolved in water, in about the following proportions, though
I do not bind myself to these proportions.
140 to 175 grains ferric ammonic citrate in 3 ounces water.
120 to 150 grains potassic ferri-cyanide in 3 ounces water.
The above solutions are then mixed
The solution of these two materials is brushed over a piece say of bleached
cotton cloth of any required size, or the pieces of cloth may be dipped into the
solution, the operation being done in a dark place.
The excess of solution is now pressed out by means of say pressing rollers or
any other suitable method and in this condition the sheets are carefully dried
in the dark.
The sensitized sheets are now used for printing in the usual way known to
photographers and engineers from photographic negatives or drawings made on
thin transparent paper or cloth. After printing it is only necessary to wash out
the unchanged or soluble material by means of water whilst the changed portion
which is blue being insoluble remains.
It is important that the blue prints should be well washed in water in
order to eliminate all unchanged chemicals and in order to do this more effectually
I may digest them in a dilute solution of hydrochloric acid and afterwards well
wash in pure water.

page_text: As stated in my Provisional Specification I make no claim whatever to the
above process, but use it or its equivalent for the purposes of my invention, which
though dependent on having this photographically produced blue print, as a
starting point is a distinctly after process.
Now, the essence of my invention consists in utilizing the iron contained in
the blue colouring matter as above produced by actinic light, and making it
the medium or base for the formation of another colouring matter, which is more
intense, beautiful and permanent.
In other words I use the iron in the blue as a mordant in the same way
as calico printers purposely fix oxide of iron on cotton cloth as a preliminary
in the dyeing of purples blacks, greys etc.
When cotton cloth on which there has been fixed an oxide of iron is subjected
to certain dyeing materials such as alizarin or logwood, purples and blacks are
produced, the first named material producing a well known and highly esteemed
coloured lake known as madder or alizarin purple and is one of the most per-
manent colouring matters known.
Now my chief novelty consists in utilizing the fact that the blue colour referred
to being an iron compound acts as if oxide of iron alone were fixed on the cloth
and it can therefore be used as a mordant or in other words as a basis for the
formation of purples and blacks.
For the purposes therefore of my invention I use a photographically produced
blue print on any suitable material-though I prefer cotton cloth.
The blue prints are subjected to the action of a dye bath containing any or
all of the following dyeing materials added to a considerable volume of water,
madder, alizarin, purpurin, or logwood.
The blue prints are preferably entered into the dye-bath at a temperature of
about 100° F. and the temperature gradually raised in 30 or 40 minutes to the
boiling and agitated during the whole time. They are then well washed in
clean water and afterwards treated to a boiling soap solution. They are then
well washed, dried, pressed, and if desired starched, and mounted in any desired
manner.
!
It must be understood that in mentioning the three first named materials I
may use any preparation or modified form thereof. For instance madder is a
root of a plant called Rubia tinctorum and contains alizarin and small quantities
of purpurin, but it has been almost entirely displaced in the arts by artifiical
alizarin notwithstanding this it may in some cases be preferable to use it and
certain preparations therefrom such for instance as garancin which was formerly
prepared from madder in large quantities.
In the same manner there are certain modified forms of purpurin such as
flavo-purpurin any of which I may use. In fact alizarin of commerce contains
more or less of all these materials.
According to my most recent experience I prefer to use commercial alizarin
containing this material in its purest form.
Having now particularly described and ascertained the nature of my sail
invention, and in what manner the same is to be performed, I declare that what
I claim is
1. The method of producing a purple, lilac, or black coloured design, portrait
landscape, or print, on cotton or other suitable fabric produced by a dyeing opera-
tion such as described upon a photographically produced blue print, the dyeing
materials being alizarin purpurin, madder logwood or any modification, prepara-
tion or combination thereof.
2. A design, portrait, landscape or print on cotton cloth or other suitable fabric
produced by the presence of a purple coloured lake deposited thereon and con-
sisting of alizarin, purpurin or their modifications, combined with iron or its
compounds, which iron has been previously deposited or fixed, as one of the
constituents of a blue colour by photographic methods substantially as described.

page_text: 3. A design, portrait, landscape or print, on cotton cloth or other suitable
fabric produced by the presence of a black or grey coloured lake deposited thereon,
and consisting of the dyeing principles of logwood, combined with iron or its
compounds, which iron has been previously deposited or fixed as one of the con-
stituents of a blue colour by photographic methods substantially as described.
4. Any combination of the purple, black or grey coloured lakes, described for
the said purposes in my Claims 2 and 3.
Dated this 22nd day of August 1899.
ANDREW FULLER HARGREAVES.