Year: 1896

page_text: 1, VALENTIN VAUCAMPS, of 21 Boulevard Poissonnière, Paris, in the Republic of
France, Chemist do hereby declare the nature of this invention to be as follows:
The process of chromophotography, which forms the subject of the present inven-
tion, is based upon the researches which I have made with the object of determining
the constitution of photographic plates. On the subject of this constitution I
have made the following determinations from which I have deduced the principles
which serve as a basis for my invention.
The colours of objects photographed make an impression upon the sensitized
plate or film of the photographic negative each after its manner and in a different
fashion. It is the same with lighted or obscure parts. They create, in the
negative, differences of transparency of the sensitized layer in a perfectly defined
order extending from the indigo of the solar spectrum to red.
From this it follows that the transparent parts and the lightest half-tints of the
negative correspond inversely to the obscure parts or to the dark half tints of the
object photographed, and that for coloured parts as well in their complete totality
as in their half tints the darkest parts of the negative correspond to the actions
of the coloured rays upon the sensitized layer, that is to say they gradually increase
in intensity from the red to the indigo of the spectrum.
Accordingly it may be said that when once the negative is obtained the varia-
tions in transparency which it presents are in the order of the tonalities and of the
colours, of which it has received the impression. If, then, I reproduce upon the
picture obtained with this negative and in suitable order the causes which have
determined upon the negative the action of the object photographed, this will be
the object itself which is reproduced upon the picture.
I have hereinbefore stated that the differences in transparency of the negative
follows an order extending from the indigo of the solar spectrum to red; it is
therefore with a view to this order that the sensitive layer of the picture has to be
constituted.
The following is the manner in which I effect this object:
In order that the explanation of my process may be rendered easier I will suppose
that it is desired to reproduce an object presenting three colorations only, that
is to say blue, yellow and red.
The negative made from this object will present different degrees of transparency,
in the order of the colours. Thus it will be very transparent in the parts corre-
sponding to red, dark in those corresponding to yellow, and still darker in those
corresponding to blue: therefore it shows differences of opacity corresponding to
the colours of which it has received the impression.
For reproducing these differences upon the picture and translating them into
colorations similar to those of the object I proceed in the following manner:

page_text: Upon an appropriate surface I spread a first layer which is sensible or sensitized
or which will be sensitized later on prior to the exposure to the light, which
have coloured red beforehand; upon this layer I spread a second yellow colour
and then upon this a third blue colour.
If I expose the surface thus prepared to the action of the light under the correspond
ing negative I obtain an impression of the sensitive layer which is very strong for the
most transparent part of the negative (that corresponding to red) and which will
thence continually lessen, passing through the part corresponding to yellow to the
part corresponding to blue.
The following will take place at the time of the development, for example of a
picture with mucilage bichromated in lukewarm water after transfer and after
removal of the paper which supported it before this transfer.
As in consequence of the said transfer the red is at the surface, the parts of the
layer which enclose it and which have been reached by the light are insoluble, the
cthers will be dissolved and will lay bare the layers enclosing the yellow colorations,
whose parts reached by the light will be insoluble and the others not reached
will be dissolved, allowing to appear the parts of the blue layer reached by the
light and whose parts not reached by the light will be dissolved in their turn and
allowed to appear the support if there are white parts in the object photographed..
Accordingly the picture will reproduce in an identical order the colorations of
the photographed object, which have made an impression upon the negative.
From the foregoing it will be seen that the means which I use for reproducing
the colorations of the object photographed consist in covering a suitable surface
with successive sensitive or sensitized layers or layers which are subsequently
sensitized prior to the exposure to the light, in which I incorporate beforehand
colours in such a manner that the whole of these successive layers, which constitute
the material of which the picture is formed, corresponds to the more or less trans-
parent parts, which in the negative is determined by the exposure of the latter in
the dark-chamber in the presence of the subject to be photographed.
The picture being thus constituted of successive sensitive or sensitized layers,
diversely coloured, is then exposed under the negative in the ordinary manner.
When the exposure has taken place the various layers of the picture have received
an impression according to the nature of the negative and it is sufficient to develop
the picture as hereinbefore specified for laying bare the coloured surfaces or the
parts of these surfaces so that the negative encloses them in the state of more or
less transparent tints.
It will be understood that with my process, by multiplying the number of layers
of the pictures so as to introduce into the same the scale of the colours with their
han tints, I succeed in producing coloured images reproducing subjects with tha
most diverse colorations and with the degree of intensity of these colorations.
In lieu of the order of the colours hereinbefore stated I may also invert this
order to obtain optional or imaginary effects.
It will scarcely be needful for me to add that any colours and any colouring
materials, which may be incorporated in the sensitive or sensitized layers or such
as may be sensitized of which I form my pictures, are suitable for my process
without any need for specifying them otherwise.
The same is the case with materials which are sensitive themselves or which must
be sensitized, which I arrange one above the other in order to form my pictures;
these materials may be any one of those heretofore used in photography, and I
may employ them either together or separately in order to form layers of the same
composition or of different composition upon the same picture so as to modify,
according to the requirements of the photographed subject, the effects of the
sensitiveness during the exposure.
Lastly, I may constitute my pictures either in the state of plates or in the state
of papers, or in the state of films.
In the case of films I may colour them either by preserving their transparency

page_text: or by rendering them semi-transparent by the incorporation of a white colour or
of any colours or tints to form a ground at the same time as a support for one or
more of the coloured layers herein before described.
For the manufacture of my plates, films or papers I may proceed by letting a
layer dry before pouring another on the top when use is made of one of the
sensitive materials or materials which must be sensitized as herein before mentioned,
including gelatine. However, in the case of this latter body I prefer to allow the
first deposited layer to set by lowering if necessary its temperature by artificial
means; I then pour upon this first layer thus set and cooled, but not yet dried, the
second layer, the mixture of which has previously been melted in a water-bath at
a temperature of +45 or 55 degrees, then brought to + 30 or 40 degrees prior to the
pouring on, and so forth to the last layer; by this means the gelatinous mixture
ready to be poured on possesses a sufficient degree of heat for remaining fluid
without however being hot enough for melting the humid and set layer upon
which it has to be spread. I vary moreover the temperature according to the
quantity of gelatine contained in the mixture, the quality of the gelatine and the
ambient temperature at the moment of the pouring on.
This mode of procedure imparts to the different layers a great adhesion between
each other; they are no longer susceptible of splitting up in the dry state or in
the development, which often occurs with layers placed in the fluid state upon
layers which are already dry.
The picture hereinbefore referred to must be regarded by reflection, for by
transparency the effect is no longer the same by reason of the superposition of the
coloured layers existing below those which the development has rendered visible by
reflection. With the aid of a simple manipulation I may however render the same
pictures visible by transparency or by reflection.
In this case I effect the development upon paper coated with collodion or india-
rubber, and I transfer the picture upon a very plane glass plate. The reliefs which
the development had caused at the surface of the picture being forced to the rear
in contact with the plane of the glass plate reappear naturally at the back of the
picture. But it should be observed that these reliefs contain coloured layers.
which remain without effect in the result obtained, because they are masked by
those which the development has alone laid bare. If I remove, what may take
place in the dry or in the moist state with the aid of a grindstone or any other
means, these layers which now form projections at the back of the picture, there
will adhere to the glass plate only the layers or the parts of coloured layers
which contribute to the formation of the picture, and the latter will then be
visible as well by transparency as by reflection.
The presence of reliefs at the surface of the pictures or the photographic negatives
may also be utilized in another manner for the mechanical reproduction of a greater
or smaller number of copies of the said negatives or pictures.
For this purpose I proceed in principle as follows:
I take a negative or a picture obtained by the processes herein before set forth,
that is to say containing the coloured layers which the development has reached to
a greater or smaller depth, giving rise to the reliefs on the same. I place the
relief upon the table of a reproducing machine, such as machines for manufacturing
musket stocks or certain machines for carving. Around the type picture I
arrange plates composed of superposed and coloured layers resembling as regards
sensitiveness those which I use for my photographic pictures. Over all the parts
of the surface of the type I pass a blunt point which follows all the reliefs and
which, with the aid of levers connected with it, transmits all its movements to
tools which scoop out the surface of the plates. It is easy to understand that by
this means the tools will scoop the surfaces of the coloured coats of the plates, and
that if the superposed layers of these coats are equal in thickness to the layers of
the type the same undulations of the surface reach the same depth, the tools lay
bar at the same places the corresponding layers with coloration. Thus I obtain

page_text: in this manner and owing to the principle of the superposition of the coloured
layers, which forms the basis of my invention, pictures which reproduce faithfully
the type which serves as a model.
Dated this 21st day of September 1896.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.
Improvements in and relating to Chromophotography.
I, VALENTIN VAUCAMPS, of 21 Boulevard Poissonnière, Paris, in the Republic of
France, 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:-
The process of chromophotography which forms the subject of the present inven-
tion is based upon the researches which I have made with the object of determining
the constitution of photographic plates. On the subject of this constitution I
have made the following determinations from which I have deduced the principles
which serve as a basis for my invention.
The colours of objects photographed make an impression upon the sensitized
plate or film of the photographic negative each after its manner and in a different
fashion. It is the same with lighted or obscure parts. They create, in the
negative, differences of transparency of the sensitized layer in a perfectly defined
order extending from the indigo of the solar spectrum to red.
From this it follows that the transparent parts and the lighest half-tints of the
negative correspond inversely to the obscure parts or to the dark half tints of the
object photographed, and that for coloured parts as well in their complete totality.
as in their half tints the darkest parts of the negative correspond to the actions
of the coloured rays upon the sensitized layer, that is to say they gradually increase
in intensity from the red to the indigo of the spectrum.
Accordingly it may be said that when once the negative is. obtained the varia-
tions in transparency which it presents are in the order of the tonalities and of the
colours, of which it has received the impression. If, then, I reproduce upon the
picture obtained with this negative and in suitable order the causes which have
determined upon the negative the action of the object photographed, this will be
the object itself which is reproduced upon the picture.
I have herein before stated that the differences in transparency of the negative
follows an order extending from the indigo of the solar spectrum to red; it is
therefore with a view to this order that the sensitive layer of the picture has to be
constituted.
The folowing is the manner in which I effect this object:
In order that the explanation of my process may be rendered easier I will suppose
that it is desired to reproduce an object presenting three colorations only, that
is to say blue, yellow and red.
The negative made from this object will present different degrees of transparency,
in the order of the colours. Thus it will be very transparent in the parts corre-
sponding to red, dark in those corresponding to yellow, and still darker in those
corresponding to blue: therefore it shows differences of opacity corresponding to
the colours of which it has received the impression.
For reproducing these differences upon the picture and translating them into
colorations similar to those of the object I proceed in the following manner:

page_text: Upon an appropriate surface I spread a first layer which is sensible or sensitized,
or which will be sensitized later on prior to the exposure to the light, which I
have coloured red beforehand upon this layer I spread a second yellow colour,
and then upon this a third blue colour.
If I expose the surface thus prepared to the action of the light under the correspond-
ing negative I obtain an impression of the sensitive layer which is very strong for the
most transparent part of the negative (that corresponding to red) and which will
thence continually lessen, passing through the part corresponding to yellow to the
part corresponding to blue.
The following will take place at the time of the development, for example of a
picture with mucilage bichromated in lukewarm water after transfer and after
removal of the paper which supported it before this transfer.
As in consequence of the said transfer the red is at the surface, the parts of the
layer which enclose it and which have been reached by the light are insoluble, ihe
others will be dissolved and will lay bare the layers enclosing the yellow colorations,
whose parts reached by the light will be insoluble and the others not reached
will be dissolved, allowing to appear the parts of the blue layer reached by the
light and whose parts not reached by the light will be dissolved in their turn and
allowed to appear the support if there are white parts in the object photographed.
Accordingly the picture will reproduce in, an identical order the colorations of
the photographed object, which have made an impression upon the negative.
From the foregoing it will be seen that the means which I use for reproducing
the colorations of the object photographed consist in covering a suitable surface
with successive sensitive or sensitized layers or layers which are subsequently
sensitized prior to the exposure to the light, in which I incorporate beforehand
colours in such a manner that the whole of these successive layers, which constitute
the material of which the picture is formed, corresponds to the more or less trans-
parent parts, which in the negative is determined by the exposure of the latter in
the dark-chamber in the presence of the subject to be photographed.
The picture being thus constituted of successive sensitive or sensitized layers,
diversely coloured, is then exposed under the negative in the ordinary manner.
When the exposure has taken place the various layers of the picture have received
an impression according to the nature of the negative and it is sufficient to develop
the picture as hereinhefore specified for laying hare the enloured surfaces or the
parts of these surfaces so that the negative encloses them in the state of more or
less transparent tints.
It will be understood that with my process, by multiplying the number of layers
of the pictures so as to introduce into the same the scale of the colours with their
half tints, I succeed in producing coloured images reproducing subjects with the
most diverse colorations and with any degree of intensity of their colorations.
In lieu of the order of the colours hereinbefore stated I may also invert this
order to obtain optional or imaginary effects.
It will scarcely be needful for me to ada that any colours and any colouring
materials, which may be incorporated in the sensitive or sensitized layers or such
as may be sensitized of which I form my pictures, are suitable for my process
without any need for specifying them otherwise.
The same is the case with materials which are sensitive themselves or which must
he sensitized, which I arrange one above the other in order to form my pictures:
these materials may be any one of those heretofore used in photography, and I
may employ them either together or separately in order to form layers of the same
composition or of different composition upon the same picture so as to modify,
according to the requirements of the photographed subject, the effects of the
sensitiveness during the exposure.
Lastly, I may constitute my pictures either in the state of plates or in the state
of papers, or in the state of films.
In the case of films I may colour them either by preserving their transparency
or by rendering them semi-transparent by the incorporation of a white colour or

page_text: of any colours or tints to form a ground at the same time as a support for one or
more of the coloured layers hereinhefore described.
For the manufacture of my plates, films or papers I may proceed by letting a
layer dry before pouring another on the top when use is made of one of the
sensitive materials or materials which must be sensitized as hereinbefore mentioned
including gelatine. However, in the case of this latter body I prefer to allow the
first deposited layer to set by lowering if necessary its temperature by artificial
means; I then pour upon the first layer thus set and cooled, but not yet dried, the
second layer, the mixture of which has previously been melted in a water-bath at
a temperature of +45 or 55 degrees, then brought to + 30 or 40 degrees prior to the
pouring on, and so forth to the last layer; hy this means the gelatinous mixtu
ready to be poured on possesses a sufficient degree of heat for remaining Huid
without however being hot enough for melting the humid and set layer upon
which it has to be spread. I vary moreover the temperature according to the
quantity of gelatine contained in the mixture the quality of the gelatine and the
ambient temperature at the moment of the pouring on.
This mode of procedure imparts to the different layers a great adhesion between
each other; they are no longer susceptible of splitting up in the dry state or in
the development, which often occurs with layers placed in the fluid state upon
layers which are already dry.
The picture hereinbefore referred to must be regarded by reflection, for by
"transparency the effect is no longer the same by reason of the superposition of the
coloured layers existing below those which the development has rendered visible by
reflection. With the aid of a simple manipulation I may however render the same
pictures visible by transparency or by reflection.
In this case I effect the development upon paper coated with collodion or india-
rubber, and I transfer the picture upon a very plane glass plate. The reliefs which
the development has caused at the surface of the picture being forced to the rear
in contact with the plane of the glass plate re-appear naturally at the hack of the
picture. But it should be observed that these reliefs contain coloured layers.
which remain without effect in the result obtained, because they are masked by
those which the development has alone laid hare. If I remove, what may take
place in the dry or in the moist state with the aid of a grindstone or any other
'means, these layers which now form projections at the back of the picture, there
will adhere to the glass plate only the layers or the parts of coloured layers
which contribute to the formation of the picture, and the latter will then be
visible as well by transparency as by reflection.
The presence of reliefs at the surface of the pictures or the photographic negatives
may also be utilized in another manner for the mechanical reproduction of a greater
or smaller number of copies of the said negatives or pictures.
For this purpose I proceed in principle as follows:-
I take a negative or a picture obtained by the process as hereinbefore set forth,
that is to say containing the coloured layers which the development has reached
to a greater or smaller depth, giving rise to the reliefs on the same.
I place this relief upon the table of a reproducing machine, such as machines
for manufacturing musket stocks of certain machines for carving. Around the
type picture I arrange plates composed of superposed and coloured layers resembling
as regards sensitiveness those which I use for my photographie pictures. Over
all the parts of the surface of the type I pass a blunt point which follows all the
reliefs and which, with the aid of levers connected with it, transmits all its move-
ments to tools which scoop out the surface of the plates. It is easy to understand
that by this means the tools will scoop the surfaces of the coloured coats of the
plates and that if the superposed layers of these coats are equal in thickness to the
layers of the type the same underlations of the surfaces reach the same depths,
the tools lay bear at the same places, the corresponding layers with coloration.
Thus I obtain in this manner and owing to the principle of the superposition of the

page_text: colored layers, which forms the basis of my invention pictures which reproduce
faithfully the type which serves as a model.
Having now particularly described and ascertained the nature of my said Inven-
tion, and in what manner the same is to be performed, I declare what I claim
is:-
1. The process for obtaining photographic images in colours, characterized by
the construction of plates, papers, films and the like with the aid of sensitive layers
or layers which have to be sensitized, placed one above the other and in which are
incorporated colours or tints or the like, the said layers thus coloure 1 being placed
in the order of the coloration of the solar spectrum or in a different order with the
object of obtaining, after exposure under a photographic negative and after
development, the laying bare of the whole or part of the coloured layers thus
allowing to appear the lower coloured layers, as hereinbefore specified.
2. The process of producing superposed layers, by allowing the still moist lower
layer to set if necessary by artificial cooling, before pouring on the layer which is
to cover the same, with the object of obtaining a perfect adhesion between them,
as hereinbefore specified.
3. The transformation of images seen by reflection into images visible by trans-
parency, by removing from the back of these images the layers or parts of coloured
layers which are useless inasmuch as they do not contribute to the general effect
as hereinbefore specified.
4. The removal with the aid of a mechanical reproducing tool, of the whole or
part of the coloured and superposed layers of my plates, papers, films, or the like,
for producing upon a great number of these plates, papers, and films, and at the
same time, the effects of coloration obtained by the superposition of the coloured
layers as herein before specified.
5. The employment of colourless or coloured layers forming transparent or
semi-transparent films to constitute a ground at the same time as a support for one
or more coloured layers, as herein before specified.
Dated this 19th day of June 1897
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.