The Portland daily press. [volume] (Portland, Me.) 1862-1921, 1888-03-30
PHoTocRAPHic WONDERS.
Watch DIals Made by Sun Process
Plate Glass Designs.

''Do you know that watch dials are now
made by photography at mere fraction Of
their former cost? ?" said an expert in such
matters to New York Sun writer. They
all used to be painted by hand. Now hun
bred are made in the time formerly required
to produce one, and each of the hundred is
better than the one would have been. The
dial is of copper covered with enamel. Upon
that they lay a sensitized coating of albumen
and bicromate of potash. A large drawing,
say. IL inches In diameter, Of the design, ng-
ures and dots that it is desired to put upon
the dial is photographed down to the requir-
ed size, which makes it so very fine that
whatever inaccuracies may have been in the
drawing are almost beyond discovery by the
microscope. The negative thus made Is ex-
posed to the light in contact with the gelatine
coated watch dial from three TO five minutes.
Electric light Is just as good as sun light.
Where the light has acted the gelatine is
made insoluble The dial is now linked over
with common photographic transfer ink.
Next, with clean sponge moistened with a
little gum water, the ink and gelatine are
wiped off the dial from all parts except where
the light has acted, and to those it adheres,
leaving the design in clear black upon the en-
amelled plate. But that design would easily
blur and rub OF by wear. Another process
is necessary to make it permanent. A metal
lie enamel powder OF any color desired-black
blue green, red or purple-iS busted upon
the dial. 1t sticks to the linked portions, but
nowhere else. Then the dial is put in the
muffie and fired. The enamel powder melts
into the white enamel base, and the work Is
complete. The Waltham Watch Company
paid $1,000 for that process. BY it they can
turn out, for 10 cents each, dials that in the
old way of making would have cost 81
apiece.
"By that same process, with some trivial
notifications in certain directions, photog-
raphy is also employed now in putting pict-
ures, monograms and other designs upon p0r-
eeain and china but there is yet field there
for further Improvement in the use of c0lored
enamels in that branch Of photographic dec
Grafton.
photography is now used also for the pro-
duction of the most beautiful engraved pict-
ures and designs upon plate glass for car
windows, screens, etc. A plate glass having
been coated with sensitized gelatine, has
transferred to 1t picture. The soluble parts
of the gelatine, those upon which the light
has not acted, are readily washed off. When
those remaining are dry, the plate is sub
jected to the action of very fine sand blast.
The most delicate dots and lines OF the gela-
tine protect perfectly the glass beneath them
glass and make it Opaque. When that has
been done, the gelatine is readily dissolved
and removed, leaving the picture complete.
1t is a rapid, easy process, and may be so
handled as to give charming results. OF
course you understand that the picture for
transfer must be in dots and lines. The hall
tone pictures directly photographed from ma
ture or from oil paintings cannot be SO en-
nlnypd -