Improvements in the Manufacture of Colours, specially applicable for Colouring Photographs.
Year: 1892

page_text: Date of Application, 26th Feb., 1892-Accepted, 18th June, 1892
COMPLETE SIECIFICATION.
Improvements in the Manufacture of Colours, specially applicable
for Colouring Photographs.
[A communication from the firm of CARL HEINRICH WILHELM BRUNS, of
Halberstadt, in the German Empire, Chemical Works.]
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., 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 :-
Although the colouring of photographs is both a lucrative and pleasant occupa-
tion, specially trained people only have hitherto been able to devote themselves to
it, chiefly for the reason that there have been no colours exactly suitable for the
purpose, either the ordinary oil-colours or water-colours having been resorted to.
It is however a fact that these colours do not without difficulty adhere to the
surfaces of photographs which have been fixed, glazed with collodion, and generally
treated for photographic purposes. It is therefore necessary to submit the colours
to certain rather complicated preparatory operations, for example to mix them with
certain liquids, the nature of which is in many cases the secret of the individual
artist performing the work. Besides the colours hitherto used always entirely
cover and conceal from view those delicate shades which form one of the peculiar
advantages of photography, so that the general effect of the photograph, after
colouring, is spoiled, as in no case is it possible to convert a photograph into a real
oil-painting. When coloured photographs have to be subsequently varnished with
collodion or otherwise glazed, it has generally been found that the colours were
unfit for the reception of such varnish or glazing and that the whole picture was
spoiled in consequence.
The new colours obtained by the process which forms the subject of this
invention enable photographs to be coloured, without requiring any preparatory
operation. The colouring of photographs is thus placed within reach of the general
public and is not confined to professional hands, and any lover of such work can
colour a photograph in a few minutes. The original shades of the photograph are not
only not concealed, but rendered more prominent, and the resulting pictures present
the appearance of a water-colour painting which in colours is the nearest approach
to photography, the glossy and yet somewhat dull colouring admirably suits the
nature of a photograph. The colours adhere to any photographic surface whether
or not treated with collodion, and if the picture be collodionized or glazed after-
wards, it is in no way damaged. These colours which the inventor describes as
transparent glazing colours are prepared in the following manner,
"
In about
Cascine entirely freed from fatty substances (say by means of the Soxhlets fat-
extracting apparatus and by treatment with sulphuric ether) is allowed to dry for
about 12 hours, during which time the ether that may have been left in it
evaporates, and the caseine becomes fit for the subsequent treatment.
1250 grammes of water, on the other hand 110 grammes of borax are dissolved.
This solution is mixed with 1 kilogramme of the prepared caseine. Then while the
mixture is continually stirred it is heated to the boiling point; but a moment before
the boiling point is reached the stirring is discontinued and the impurities rising to
the surface are removed by means of a skimming ladle. After allowing the mass
thus skimmed to boil a few minutes longer it is cooled in a water bath.
The result is a liquid which by being thoroughly mixed with the desired colouring
matters, will produce colours for photographs such as have been above described
and which may moreover according to requirements be mixed with or diluted in
water without undergoing any alteration as regards their essential properties.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondents, I declare that what I claim is,-
1. The manufacture of colours suitable for colouring.photographs and capable of
adhering to paper treated for photographic purposes, consisting in dissolving the
colouring matters in and mixing them with caseine boiled in water with the addition
of borax substantially as described.
2. The herein described manufacture of colour suitable for colouring photographs
substantially as described.
Dated this 26th day of February 1892.
ALFRED J. BOULT,
Chartered Patent Agent.