Improvements in Colour Photography.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in Colour Photography.
I, LOUIS ANTOINE GARCHEY, of The Demi-Lune, near Lyons, France, Ceramic
Manufacturer, do hereby declare the nature of this invention to be as follows:-
All photographic processes by powdering hitherto described are based upon
bichromate solutions as devised by Poitevin. The chief objection to these solu-
tions is the fragility of the film which on washing in most cases disappears or
is damaged, thus destroying the photograph.
One object of my invention is to strengthen this film by incorporating a rein-
forcing substance with the emulsion. Collodion presented itself but there was
great difficulty in mixing it with the sensitive emulsion. All these solutions
contain much water and if collodion were introduced it would be decomposed
forming a precipitate of cotton. In order to avoid this difficulty I have devised
the following process.
1. I first dissolve the bichromate in the least possible quantity of water, or I
employ a saturated aqueous solution.
2. With this I incorporate syrupy matter such as honey, glucose or dextrin.
3. I add alcohol and a small quantity of anti-photogenic colouring matter.
4. And, lastly, I introduce collodion which melts in the mixture without decom-
posing, or, instead of the collodion, I introduce ether and then cotton to dissolve
in it and form the collodion in the mixture.
The anti-photogenic colouring matter introduced is intended to prevent the
soft effects of the interference of luminous rays which sometimes present them-
selves on proofs on glass, opal or the like.
The emulsion prepared as above described is employed to sensitise plates and
these, after the image is developed, can be repeatedly subjected to acidulated
washings without injury, and thus very large plates may be employed, such as
could not be used when methods hitherto known are used.
For applications of photography in colour or in producing impressions in
various tints I have found it necessary to isolate the photographed and developed
film between two successive positives.
Thus before each new print I cover the film which has already on it a first
colour impression, with a layer of a weak, about 2 per cent. solution of organic
material, such as gum or gelatine. I can then apply emulsions to the negative
as often as I desire, the isolating layer preventing the new emulsion from dis-
solving the previous ones.
For producing enamels I prefer to use plates of glass, porcelain, metal or other
material that can be baked, and for developing the pictures I employ coloured
powders of vitrifiable enamels.
For producing prints on paper, paste-board, celluloid or the like, which are not
intended to be baked, I operate in the same way provided that the negatives are
in the first place made impermeable, and I develop the pictures with coloured
vegetable or mineral powders.

page_text: If, for instance, Ducas du Hauron's method of photographing with the three
fundamental colours is employed, I operate as follows:
After having printed and developed, by yellow powder for instance, and washed
with acidulated water, the bichromate film strengthened with collodion which has
been exposed to the plate forming the yellow screen, before being treated for the
other tint colours, has spread over it a layer of isolating matter and is dried.
Then a fresh emulsion can be applied, and the film can be exposed to the screen
for blue and developed and powdered with blue. After washing with acidulated
water the like operations are repeated for the red. Many other tints might be
applied if necessary.
As I have stated, my process allows of very large films being employed, but in
order to avoid the use of very large screen plates I'print by projection and direct
enlargement, and thus I can decorate large surfaces with photographs in colours.
The application of pictures in black or in colour to large glass plates is objec-
tionable because if the pictures are transparently looked at, the half tints become
thin and have only their value when the surfaces are covered with a layer of
translucent enamel.
I remedy this by first applying over the whole surface white or dull enamel
powder thus having a translucent ground for the desired colour. On this ground
I put a layer of the isolating material, sensitise afresh and develop as many times
as desired, as above described. On baking, the ground becomes indelible and the
desired effect. is obtained.
Dated this 3rd day of October 1899.
ABEL & IMRAY,
Agents for the Applicant.
crour гпосодтарцу.
I, LOUIS ANTOINE GARCHEY, of The Demi-Lune, near Lyons, France, Ceramic
Manufacturer, 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:-
-
All photographic processes by powdering hitherto described are based upon
bichromate solutions as devised by Poitevin. The chief objection to these solu-
tions is the fragility of the film which on washing in most cases disappears or
is damaged, thus destroying the photograph.
One object of my invention is to strengthen this film by incorporating a rein-
forcing substance with the emulsion. Collodion presented itself but there was
great difficulty in mixing it with the sensitive emulsion. All these solutions
contain much water and if collodion were introduced it would be decomposed
forming a precipitate of cotton. In order to avoid this difficulty I have devised
the following process.
1. I first dissolve the bichromate in the least possible quantity of water, or I
employ a saturated aqueous solution.
2. With this I incorporate syrupy matter, such as honey, glucose or dextrin.
3. I add alcohol and a small quantity of anti-photogenic colouring matter.
4. And, lastly, I introduce collodion which melts in the mixture without decom-
posing, or, instead of the collodion, I introduce ether and then cotton to dissolve
in it and form the collodion in the mixture.

page_text: The anti-photogenic colouring matter introduced is intended to prevent the
soft effects of the interference of luminous rays which sometimes present them-
selves on proofs on glass, opal or the like.
The emulsion prepared as above described is employed to sensitise plates and
these, after the image is developed can be repeatedly subjected to acidulated
washings without injury, and thus very large plates may be employed, such as
could not be used when methods hitherto known are used.
For applications of photography in colour or in producing impressions in
various tints I have found it necessary to isolate the photographed and developed
film between two successive positives.
Thus before each new print I cover the film which has already on it a first
colour impression, with a layer of a weak, about 2 per cont. solution of organic
material, such as gum or gelatine. I can then apply emulsions to the negative
as often as I desire, the isolating layer preventing the new emulsion from dis-
solving the previous ones.
For producing enamels I prefer to use plates of glass, porcelain, metal or other
material that can be baked, and for developing the pictures I employ coloured
powders of vitrifiable enamels.
For producing prints on paper, paste-board, celluloid or the like, which are not
intended to be baked, I operate in the same way provided that the negatives are
in the first place made impermeable, and I develop the pictures with coloured
vegetable or mineral powders.
If, for instance, Ducas du Hauron's method of photographing with the three
fundamental colours is employed, I operate as follows:
Atter having printed and developed, by yellow powder for instance, and washed
with acidulated water, the bichromate film strengthened with collodion which has
been exposed to the plate forming the yellow screen, before being treated for the
other tint colours, has spread over it a layer of isolating matter and is dried.
Then a fresh emulsion can be applied, and the film can be exposed to the screen
for blue and developed and powdered with blue. After washing with acidulated
water the like operations are repeated for the red. Many other tints might be
applied if necessary.
As I have stated, my process allows of very large films being employed, but in
order to avoid the use of very large screen plates I print by projection and direct
enlargement, and thus I can decorate large surfaces with photographs in colours.
The application of pictures in black or in colour to large glass plates is objec-
tionable because if the pictures are transparently looked at, the half tints become
thin and have only their value when the surfaces are covered with a layer of
translucent enamel.
I remedy this by first applying over the whole surface white or dull enamel
powder thus having a translucent ground for the desired colour. On this ground
I put a layer of the isolating material, sensitise afresh and develop as many times
as desired, as above described. On baking, the ground becomes indelible and the
desired effect is obtained.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. The herein described manufacture of a photographic bichromate emulsion
capable of being repeatedly washed without damage to the film, by incorporating
with the emulsion a reinforcing body such as collodion.
2. The addition of anti-photogenic colouring matters to photographic bichro-
mate emulsions so as to obtain clear definition in prints on any material, as
herein described.
3. In applying successive layers of emulsion such as that above referred to,
the interposition between the layers of organic isolating substances such as gela
tine and the like.

page_text: 4. The preparation of enamels on glass or the like by applying emulsion such
as that referred to in Claim 1 and developing with coloured vitrifiable enamel
powder.
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2011
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T
1000
ABEL & IMRAY,
Agents for the Applicant.