Year: 1888

page_text: Date of Application, 24th Mar., 1888
Complete Specification Left, 13th Dec., 1888
Complete Specification Accepted, 12th Feb., 1889
I, JEAN BAPTISTE GERMEUIL BONNAUD, of 39 Stroud Green Road, in the County
of Middlesex, Chemist do hereby declare the nature of this invention to be as
follows:-
The object of this invention is to produce photographs in colours by a new process,
whereby the same is done by the aid of the light simply, and not by the hand as
heretofore. The said process can be utilized by charbon, powder, chromo litho
photographic, or by any other similar method.
This process consists in the use of coloured films and in the alternate use of the
negative and the positive all the colours, or at least all the degrees of colour existing
in the latent state in these two clichés issued from the light.
A proof is taken from the positive, and a proof of the negative from the same object
is taken and laid over the proof of the positive.
The combination reproducing all the original colours.
CASTLE SMITH,
"Invention" Office,
54, Fleet Street, London, E.C.,
Agent for the Applicant.

page_text: I, JEAN BAPTISTE GERMEUIL BONNAUD of 39 Stroud Green Road Finsbury Park
in the County of Middlesex, Chemist 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:-
By this invention which is simple I am enabled to produce a painting from
photographs which it is next to impossible to distinguish from an ordinary painting
done by hand in the usual way.
According to this invention I proceed as follows. Having obtained positive and
negative transparent proofs of the picture to be colored I take a solution of
Distilled Water
Solid Glucose
Chemical Gum
200 cubic centimetres.
40 grammes.
-
24 grammes.
Bichromate of Potash (very pure) 24 grammes.
Liquid Ammonia (pure) 6 drops specific gravity 0.880.
Instead of the glucose other similar organic matter may be used such as honey sugar
treacle &c.
The solution prepared as above is carefully filtered and spread on a sheet of well
cleaned glass or other substance nonporous and having a polished surface which is
then slightly heated in any suitable apparatus until it is no longer sticky or tacky in
fact until the finger may be passed across it without feeling a stickiness, it is then
exposed to the action of light under the photographic transparent positive and when
the edges of the glass (which should exceed the size of the picture by about half an
inch) have become dark brown from the original yellow color the picture is ready to
receive the colors as hereafter described. The glass is then taken from the printing
frame in which it was placed with the positive proof for exposure to the light as above
described and then the following series of novel and curious transformations
commence.
i
Having selected the colors which are required in the picture according to the
requirements of the picture that is to say those tints which are specially applicable to
the subject of the picture as for instance in the case of a portrait of a negro I begin
with dark brown or brown black tints whereas for the portrait of a white man I begin
with a pinky gray color according to the depth of color required, again, if it is
desired to copy the picture of an old master it is necessary to begin with darker tints
than in copying a more modern picture all of which the operator will soon find out
by practice.
The necessary colors which should be vegetable colors in powder are prepared in
dishes and the dusting on is effected with a large sized brush made of soft fine hair
commencing with the dark shades and following with the half tints, the operation of

page_text: dusting on the colors should be performed as rapidly as possible, the glass (which has
now the picture upon it but without any groundwork and which hereafter I call the
picture) is then again dried but with less heat than before (in warm dry climates this
second drying is not necessary) and the picture on the glass is again exposed to the
light but this time under the negative photographic proof which must of course be
reversed and placed on the glass so that the subject may correspond. This is what is
conveyed by the provisional specification where it is stated that à proof of the negative
is laid over the proof of the positive.
The picture obtained by the first dusting protects the shades and the reverse of
the shades so obtained from the exposure under the positive is obtained from the
negative and by a second dusting after this latter exposure the different degrees of
tints are obtained necessary to complete the picture, this is done by dusting on the
more light colors representing the lighter shades in the picture such for instance as
flesh color. The juxtaposition must be absolutely correct if the negative and positive
are obtained from one another.
When the picture has undergone the two exposures aforesaid I pour on the picture
a mixture composed of boiled linseed oil and varnish dissolved in ten times their
weight of spirits of turpentine which is allowed to evaporate, any details such for
instance as a gold chain in a portrait which may he wanting must now he painted in
by hand from oil color in tubes as is usual. The picture, thus finished is removed
from the glass by means of a collodion composed exactly as follows.
Gun Cotton
Alcohol at 62°
Ether at 40°
2 grammes.
40 cubic centimetres.
60 cubic centimetres.
This collodion is poured on and is then left for some minutes to evaporate and then
I proceed as follows in order to transfer the film with the picture from the glass to
the canvas, wood or other desired material. I steep the glass carrying the picture in
water to get rid of the organic matters and the chrome salts and when these substances
are completely dissolved I steep (for a minute at the most) the glass and picture in
another bath which will subsequently destroy the collodion film, this bath is composed
as follows

page_text: When I wish to imitate water color paintings after the two exposures and dustings
herein before described I dispense with the linseed oil and varnish and oil colors and
transfer the picture immediately after the exposures and dustings direct on to the
desired material by the aid of the collodion film as above described.
After the picture is finished it is varnished in the usual way if to represent an oil
painting.
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 that what I
claim is :-
1st. The alternate use of the positive and negative proofs to produce a complete
painting with the aid of light substantially as described.
2nd. The use in some cases of a positive only and painting on the same provisional
support substantially as described.
3rd. The process for imitating an oil painting substantially as described.
4th. Removing at one operation and transferring the complete picture to canvas
wood or other material prepared for the purpose substantially as described.
5th. The process hereinbefore described for the production of paintings.
Datal thin Thistoanth love of December 1eee