IMPROVEMENTS IN PRODUCING DESIGNS UPON CARRIAGE LAMPS, WINDOWS, AND OTHER SURFACES
Year: 1880

page_text: A
PROVISIONAL SPECIFICATION left by Alexander Melville Clark at the
Office of the Commissioners of Patents on the 15th September 1880.
communication from abroad by Dominique Scotellari, of Paris, France.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN PRODUCING DESIGNS UPON
CARRIAGE LAMPS, WINDOWS, AND OTHER SURFACES." [A communication from
abroad by Dominique Scotellari, of Paris, France.]
This Invention relates principally to the production of armorial or heraldic
devices, initials, and other distinguishing or ornamental designs in vitrified colors,
upon the lamps, windows, and glazed panels of private and public carriages and
vehicles of all kinds, whether for the purposes of distinction, as, for instance, to
enable a carriage to be readily recognised at night, or in the case of carriage
windows thus ornamented, for permitting the occupant of the carriage to see out
without being seen, or for signalling to the public, or exhibiting public notices.
And the Invention consists in the production of the said heraldic dovices, initials,
and other distinguishing or ornamental designs, by means of the following
process:-
The characteristic feature of this process is that the action of light is caused to
modify the nature of a preparation or conting previously applied on the surface to
be ornamented, this modification taking place only in certain parts, and having for
effect to modify or leave unchanged, as the case may be, the adhesive property of
the coating.
I first coat the surface to be ornamented with what is called enamel collodion.
For this coating I employ by preference the following composition :-
Distilled water
1000 grammes.

page_text: should be performed in the dark room; this done, the image is printed on the
surface from a positive, either by contact in the printing frame, or by projection in
an enlarging or reducing camera. After a few minutes exposure the image is
developed in the dark room by the application of enamel or glass powder with
a badger hair brush, until the image appears with the desired sharpness and
intensity.
When the development is finished, I fix by firing in an oven at a high temperature.
In the case of large plates, instead of making the powdered vitrifiable colors adhere
by means of a brush, I operate as follows:-The glass plate on which the image has
been produced, is made to form one of the sides of a box in which the enamel
powder is placed. All the sides of this box being transparent, the charging the
plate with enamel powder can be easily watched, and when sufficiently charged,
the adhesive deposit is allowed to remain at least 3 days, and is then immersed for
12 hours in a bath of plain water, which removes the yellowish coating colored by
the bichromate, which would prejudice the firing, or would leave on the plate a
greenish yellow tint. This washing having removed a part of the flux of the
enamel, it is replaced (when the plate is dry) by a solution of borax at 10 per cent.,
by applying with a badger hair brush over the whole surface a coat of a solution of
4 parts of spirit of turpentine, and 1 part of fat spirit. In this state the plate
is colored by means of metallic oxides and salts, silicates and enamels employed in
painting on glass which aro applied by means of spirit on the right side, or preferably
with gum on the back surface of the plate. Water or gum colors are applied to
_heighten the.effect,.and_the_whole is fixed by firing at a high temperature.