IMPROVEMENTS IN PHOTOGRAPHY
Year: 1851

page_text: SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM.
HENRY FOX TALBOT, of Laycock Abbey, Chippenham, in the County of
Wilts, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twelfth day of June
(One thousand eight hundred and fifty-one), in the fourteenth year of Her
reign, did; for Herself, Her heirs and successors, give and grant unto
me, the said William Henry Fox Talbot, my exors, admors, and assigns, Her.
especial license, full power, sole privilege and authority, that I; the said
William Henry Fox Talbot, my exors, admors, and assigns, or such others as
I, the said William Henry Fox Talbot, my exors, admors, or assigns, should at
any time agree with, and no others, from time to time and at all times during-
the term of years therein expressed, should and lawfully might make; use,
exercise, and vend, within England, Wales, and the Town of Berwick-upon-
Tweed, my Invention of "IMPROVEMENTS IN PHOTOGRAPHY;" in which said.
Letters Patent is contained a proviso that I, the said William Henry
Fox Talbot, shall cause a particular description of the nature of my said
Invention, and in what manner the same is to be performed, by an instru-
ment in writing under my hand and seal, to be inrolled in Her said Majesty's
High Court of Chancery within six calendar months next and immediately,

page_text: after the date of the said in part recited Letters Patent, as in and by the
same, reference being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
William Henry Fox Talbot, do hereby declare that the nature of my said
Invention, and the manner in which the same is to be performed, are fully
described and ascertained in and by the following statement thereof, that is to
say:
The first part of, my Invention is a new method of producing photographic
images upon plates of glass. For this purpose a plate of glass is selected with
a clean well polished surface, and the image is produced upon it by means of
the following operations :-
1. Take the albumen or white of an egg and separate the most liquid
portion of it, which is alone to be used, rejecting the rest, add to this an equal
measure of water and mix thoroughly, then spread the albumen upon the
glass very evenly and uniformly, and dry it at the fire, or else suffer it to dry
spontaneously.
2. Mix an aqueous solution of nitrate of silver with a large proportion of
alcohol, so that the mixture may contain about three grains of the nitrate in
an ounce of the liquid. This proportion may be varied from one to six grains,
but three grains, or thereabouts, appears to me the best proportion.
3. Dip the prepared glass plate into this solution for a few seconds, then
withdraw it and suffer it to dry spontaneously or with the aid of gentle
warmth.
4. Dip the plate into distilled water, in order to remove any superfluous
portions of nitrate of silver.
:
5. Spread a second coating of albumen upon the glass similarly to that
above described' under Number 1, then dry the plate with gentle warmth,
but avoid the use of strong heat; which might cause a' decomposition of the
nitrate of silver.
6. Take an aqueous solution of protiodide of iron containing about one
hundred and forty grains of the protiodide-in-one ounce of water. A small
quantity of free iodine in the solution, giving it a yellow colour, appears to be
of advantage. Mix together one measured portion of this solution, one of
acetic acid, and ten of alcohol: It is best to allow the mixture to rest one' or
two days before employing it.
7: Dip the prepared plate for a few seconds into this solution of protiodide
of iron, or else allow a stream of the solution to flow uniformly over the plate.
Dry the plate with gentle warmth. It should then be of a pale yellow colour,"
and very clear and uniformly transparent. This concludes the first part of

page_text: the preparation of the plate. The preceding operations may all be performed
in moderate daylight, avoiding, however, exposure to very strong daylight or
to sunshine.
8. At the time when it is wished to make a photographic picture, take a
5 solution of nitrate of silver containing one hundred grains of the nitrate in one
ounce of water. To two measures of this add two of acetic acid and one of
water. Into this mixture dip the glass plate previously prepared in the way
above described, either once or twice, for a few seconds each time, which must
of course be performed by candlelight or in a darkened chamber. If the
weather is cold the plate should be gently warmed before so dipping it. Then
remove the plate and place it in the camera. The plate ought to be used
within a few minutes after it has been taken out of the nitrate of silver,
When the operator judges that the plate has received a sufficient strong
photographic image it is removed from the camera into the darkened chamber
or operating room.
9. The plate is then dipped into a mixture consisting of one measure of
saturated solution of sulphate of iron in water diluted with two measures of
water. The exact proportion is however immaterial, and the sulphate may,
be used stronger or weaker as experience may point out. The sulphate of
iron usually causes the rapid appearance of the previously invisible photo-
graphic image upon the plate.
10. The plate is then washed and then dipped into a rather strong solution
of hyposulphite of soda in water, which in about a minute renders every part
of the picture more distinct and visible. The picture is then washed with
distilled water, and it may be cleaned from any particles of dust or other
impurity by rubbing it gently with cotton and water, which does not injure.
the surface if the operation has been properly performed.
The picture
is then dried and the operation is finished. But to preserve it from future
accidents, the surface may be coated with transparent varnish, or with an
additional coating of albumen.
In describing the above operations I have mentioned the proportions which
appear to me to be the best in practice, but I do not confine myself to those
proportions which are susceptible of considerable variation, as in most other
photographic processes. To the pictures obtained by the above-described.
process I have given, for the sake of distinction, of the name of Amphitypes.
They appear either positive or negative, according to the light in which they
are held. If held against a bright light, or placed upon a sheet of white paper,
they appear negative. If held against a black surface, and seen by obliquely
reflected light, they appear positive. It is in the power of the operator to

page_text: cause the positive image to be more or less visible in comparison with the
negative image, by varying the proportions of the chemical substances em-
he should
ployed. If he intends afterwards to copy the picture upon paper,.
seek to obtain a strong negative image on the glass, from which a good positive
copy upon paper may be obtained in the usual way. But if he prefers to have
a picture upon glass, he should seek to obtain a strong positive image. When
obtained to his satisfaction it may be secured from injury and from contact of
the air by pouring black paint upon the pictured side of the glass, then
turning the glass the picture is seen correctly and not reversed as regards right
and left. This last-mentioned process of blackening the picture is, however,
not a part of the present Invention here claimed as new. It is necessary to
remark, that in the whole of this Specification I use the terms positive and
negative images in the sense in which they are usually employed by photo-
graphers, videlicet, positive images are those in which the lights of the object
are represented by lights and the shades by shades. Negative images are
those in which the reverse effect takes place. The above-described process is
one which I recommend, provided that the operator is making pictures of
objects in the immediate vicinity of a darkened chamber to which he can retire,
for the purpose of rendering the plate sensitive to light. But if the object
which he seeks to delineate is at a considerable distance therefrom, or if the
operator is on a journey and can obtain no convenient locality for preparing
his plates, I then recommend the following arrangement:-A glass cell is
prepared composed of two equal and parallel sheets of plate glass. The cell
is open at top, closed at the sides and bottom, and quite water-tight. It is of
sufficient length, breadth, and thickness to admit freely one of the glass plates
which the operator uses for the obtaining of his photographic images, but not
much greater, as it is of consequence not to waste the chemical liquids em-
ployed. The posterior glass of the cell has one of its surfaces ground or
unpolished, and the cell is placed in the hinder part of the camera, so that
when directed towards an object, the unpolished surface of the cell performs
the service of the sheet of ground glass, which is usually introduced into
cameras for the sake of placing the objects in the true focus of the camera.
An allowance, which experience will determine, has of course to be made in
the present instance, in consequence of the ground glass surface of the 'cel
being behind the position of the prepared or sensitive glass which is dropped
into it. The glass cell is provided with a funnel at one of its upper corners
by which it can be readily filled with liquid, and is provided with a cock and
waste pipe below, terminating in a tube of flexible caoutchouc, which may be
moved by hand to either of two receiving vessels placed below, one of which

page_text: is destined to receive the nitrate of silver made use of, which is too valuable
to be wasted, the other is to receive the other liquids employed, which are
thrown away after having been once used. Having determined by experiment
how much liquid is required to fill the glass cell nearly to the top when
containing one of the photographic glass plates, provide four bottles of
that capacity and fill them respectively with the following liquids:-The
first bottle with nitrate of silver, such as I have recommended (in the
article No. 8 above), for rendering the plates sensitive to light; the
second bottle with sulphate of iron diluted with water, as I have described
above (see No. 9); the third bottle with water, and the fourth bottle with a
rather strong solution of hyposulphite of soda in water. These four bottles
contain what is required for the formation of one picture, and are to be filled
again as often as exhausted. A stock of previously prepared glass plates (that
is to say, prepared as far as the operation above described as No. 7 inclusive)
is kept in a box, and when the operator wishes to make a picture, he can take
one of them out of the box without any risk, as they are not sensitive to the
light. He then drops it into the empty cell which is fixed in the hinder part
of the camera, and having pointed the camera to the object and adjusted the
focus, and then closed the front lens or object glass, he lets fall a curtain which
covers and conceals the glass cell, allowing only the mouth of the funnel to
be seen above, and the waste pipe below it. Care must be taken and proper
provision made, that no light enter the cell through the funnel, for which
purpose it may be connected with the cell by a bent tube if found necessary.
Things being thus prepared, the operator pours into the funnel the contents of
the first bottle (nitrate of silver) which fills the cell and renders the plate
sensitive; the operator having then the choice of two methods, viz, either
immediately to open the front lens, or object glass, by which the picture. is
impressed upon the glass plate while still immersed in fluid, or previously to
opening the lens he opens the cock and allows the nitrate of silver to pass
out through the waste pipe, and then proceeds to form the picture on a glass
surface only, wetted with the liquid and not immersed in it. If he adopts the
former method, as soon as he judges that, the picture is completed he closes the
lens, and allows the nitrate of silver to run off; he then closes the cock. He.
then pours the contents of the second bottle, containing sulphate of iron,.
into the funnel, and in half a minute allows it to flow out, and again closes the
cock. He then pours in the contents of the third bottle, containing water, and
then allows it to flow out, and closes the cock again. And lastly, he pours in
the contents of the fourth bottle, containing bydrosulphite of soda, and after a
minute or two, he opens the curtain and removes the glass plate from the cell,

page_text: and examines the picture obtained, which is now fixed and not liable to be
injured by the light. It should be now washed with distilled water, and then
placed in a box to be finally finished and varnished if thought proper after the
day's operations are terminated. A less simple contrivance, which I have also
adopted, is to have the bottles containing the four liquids just described, made
of a larger size and placed on an elevated stand; from each of them a tube
descends furnished with two stopcocks, so that the capacity of the tube in the
interval contained between the stopcocks shall be nearly equal to the capacity
of the glass cell when containing one of the photographic plates. It must
be observed that the tube and stopcocks through which it is intended to
pass nitrate of silver, should not be made of brass or copper, or if so they
should be, previously silvered or electro-plated. The ends of the four,
tubes coming, from the four vessels above mentioned, dip into the mouth
of a funnel, from the lower end of which a caoutchouc tube leads into the
mouth of the other funnel belonging 'to the glass cell previously described.
The use of this arrangement will be manifest on considering separately each of
the vessels with its tube and two stopcocks. On shutting the lower cock, and
opening the upper one, a measured portion of liquid will fill up the interval;
on then shutting the upper cock, and opening the lower one, this liquid will
flow through the funnel and caoutchouc tube into the glass cell and fill it. In
order that it may flow freely, and not be resisted by atmospheric pressure, the
.passage for the liquid through the cock is made as large and wide as possible,
with which precautions I find the arrangement to work satisfactorily. The
glass cell is the one previously described, and is, therefore, furnished with a
waste pipe and cock by which it may be emptied. Let us suppose that the
liquid employed in the first instance has been supplied from vessel No. 1, the
glass cell has then to be emptied, and filled again with liquid from the
vessel No. 2, and so on. The order of the processes,, and the nature of the
liquids is exactly the same as before described, the only difference being that
the portions of liquid are thus measured out mechanically, while in the former
and simpler arrangement they are measured out by hand in the quantities
necessary for the formation of each picture. The pictures thus formed on
glass may be transferred to paper and fixed in the usual manner. But in
fixing the paper photographs I find it useful, after washing them well, to dip
them in a hot solution of iodide of potassium, then, after, washing them again,
to place them in the usual solution of hydrosulphite of soda in order to obtain
a. more secure fixation.
In the above-described process I claim as new the mode of; preparing the
glass plates, especially the use of a weak solution of nitrate of silver imme

page_text: diately after the first coating of albumen; also, the conjoint use of protiodide
of iron and sulphate of iron upon albuminized glass plates; also, the simul
taneous production upon glass plates of images which are both positive and
negative, according to the light in which they are viewed. In the Patent
dated the Nineteenth of December, One thousand eight hundred and forty-
nine, and granted to Thomas Augustine Malone and myself, a method of
making such images upon glass is described which differs from the present
method in the prior formation of the negative image, which is afterwards con-
verted into a positive one. And also I claim as new the apparatus I have
described to be used along with a camera, enabling the operator to work
without the necessity of darkening the apartment in which he works, or of
employing a tent or other contrivance for working in the shade when taking
photographic pictures at a distance from any house. The form of the
apparatus may of course be considerably varied, but the essential point is
that the glass plate is placed in the cell in a partly prepared state, in which
it is insensible to light, and is not removed from the cell until the photographic
picture is finished, except the final washing and drying of it.
I do not
claim as new the mere use of a glass cell containing nitrate of silver, into
which the photographic plate is dropped previous to and during the formation
of the image; but I claim the addition of the stopcock and waste pipe, and
the general arrangement which renders unnecessary the removal of the plate
from the cell before the picture is finished. And I also believe the arrange-
ment of the four vessels furnished with tubes and stopcocks for pouring
measured quantities of different fluids into the glass cell to be a new one.
The second part of my Invention consists in a method of obtaining, under
certain circumstances, the photographic pictures of objects which are in rapid
motion. In a darkened apartment an electric battery is arranged, of the greatest
power which can be conveniently obtained. Suppose the moving object whose
picture is required is a wheel turning round upon its axis. The camera is
placed at a convenient distance from the object, and adjusted so as to have the
image of it in its focus. A glass plate is then taken, which has been previously
prepared in the way described in this Specification, and it is rendered sensitive
with nitrate of silver in the way also above described. It is then placed in the
camera, and the electrical battery is discharged, causing a sudden flash of
light, which illumines the object. The image on the glass plate is then
rendered visible, and the whole process finished also in the way above described,
If this process is properly performed, a distinct positive image of the moving
body will be seen upon the glass, the rapidity of the motion not affecting the
accuracy of the delineation.

page_text: With respect to this part of my Invention, I claim as new the using the
instantaneous light of an electric battery, in such way as to obtain the photo-
graphic image of a body illuminated thereby.
In witness whereof, I, the said William Henry Fox Talbot, have here-
unto set my hand and seal, this Eleventh day of December, One 5
thousand eight hundred and fifty-one.

page_text: tion of "IMPROVEMENTS IN PHOTOGRAPHY," bearing date at West-
minster, the Twelfth day of June, One thousand eight hundred and
fifty-one, to which a Specification was duly enrolled.
DISCLAIMER proposed to be filed by the said William Henry Fox Talbot,
pursuant to the provisions of the Statutes in that behalf, that is to
say:-
I, the said William Henry Fox Talbot, do hereby disclaim the following
parts of the said Specification, that is to say:-First, the part thereof com-
mencing with the words "But if the object which he seeks to delineate is at a
"considerable distance therefrom, or if the operator is on a journey and can
"obtain no convenient locality for preparing his plates," and extending from
those words, and including the same, continuously down to the words, "then
"after washing them again to place them in the usual solution of hyposulphite
"of soda, in order to obtain a more secure fixation," and including such last-
mentioned words. Secondly, the part thereof commencing with the words,
"And also I claim as new the apparatus I have described to be used along
"with a camera, enabling the operator to work," and extending from those
words, and including the same, continuously to the end of the said Specification.
My reasons for such Disclaimer are, that the parts of my said Invention so
disclaimed are of a separate character, and independent of the other parts of
my said Invention; and as to the part of my said Invention, firstly-above
disclaimed, that the use of the same has been subsequently superseded by
another Invention of mine, which I have called "The Traveller's Camera," and
which I have freely given to the public; and as to the part of my said
Invention secondly above disclaimed, my reasons are, that it is an Invention
more of a scientific than a practical nature; and as to both the parts of my
said Invention which I have so disclaimed, my further reason is, that I am
advised that in any action brought for an infringement of the said Patent
objections may be raised, which would require evidence to be adduced in
support respectively of those parts of my said Invention which I so disclaim,
thereby adding to the expense and difficulty of such action, and therefore,
although I still fully believe that I am the first and true Inventor of the said

page_text: parts of the said Invention, yet I consider it advisable to disclaim them as
aforesaid.
In witness whereof, I, the said William Henry Fox Talbot, have hereunto
set my hand and seal, this Sixth day of March, in the year of our Lord
One thousand eight hundred and fifty-four.
W. H. F. TALBOT. (L.S.)
To the Clerk of the Patents of England.
This to certify, that William Henry Fox Talbot, of Lacock Abbey, in the
County of Wilts, Esquire, has applied to me for leave to enter with
you the
above-written Disclaimer of a certain Invention, for which Letters Patent
were duly granted to him under the Great Seal of the United Kingdom,
dated the 12th day of June, 1851, a Specification to which was duly enrolled,
And having considered the said application, and no caveat having been entered
against the same, I have accordingly granted leave to the said William Henry
Fox Talbot to file his said Disclaimer pursuant to the Statute in such case
made and provided. And I hereby also certify that any action may be
brought in respect of any infringement committed prior to the filing of this
Disclaimer, notwithstanding the entry or filing the same, and pursuant to the
Statute in that case made and provided.
AND BE IT REMEMBERED, that on the Sixth day of March, in the
year of our Lord 1854, the aforesaid William Henry Fox Talbot came before
our said Lady the Queen in Her Chancery, and acknowledged the Disclaimer
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Disclaimer aforesaid was stamped according to
the tenor of the Statute made for that purpose.
Enrolled the Eighth day of March, in the year of our Lord One thousand
eight hundred and fifty-four.