The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1898-01-26
COLOR PHOTOGRAPHY.
As Yet 1t Is in Primitive Stage
of Development.
London Standard.

London Standard.
Some exaggerated estimates have been formed
as to the success attained by Professor Lipp-
mann in his attempts to obtain color in photog-
raphy. These should be corrected by a more
careful consideration of his lecture at the So
ciety of Arts the other night. The interval which
has elapsed since he first exhibited and ex-
planned his results TO the Royal Society in the
spring OF last year has, of course. enabled him
to attain to greater perfection in his process;
but in the strict of the word he has not
solved the problem of photography in colors The
phrase ordinarily understood means that,
either in a negative in print from one, 90
jectS would appear to be of the same color as
in the least deprecate the scientific interest and
value of Professor Lippmann's remarkable dis
covery. In itself it is almost more wonderful
than if he had actually obtained the result at
which photographers have been aiming for some
years past. One of his negatives when looked
at in the ordinary way would not exhibit colors.
1t must be viewed in particular aspect and
under special circumstances. Suppose a color
photograph be desired. for example, of a red
coat. transparent Photographic film must be
placed in contact with a metal mirror during
exposure. That ended, the plate is developed
and fixed by the usual processes, the result be-
ing that IL view the picture by reflected light
transparency of the film is condition of very
great Importance but the presence of the mir
ror during the process is absolutely essential.
Without the result possibly might be OBJ
tanned. though 1t would be very imperfect and
unsatisfactory; without the other the failure
would be complete. The chemical nature of the
film itself seems to be a matter of secondary
Importance, provided it be suitable for the ordi-
nary purposes of the photographer.
If il will give. by means of appropriate devel-
opment, a fixed colorless photograph, thiss when
backed by the mirror, will exhibit a fixed color
photograph. But to obtain a fully transparent
film is by means an easy task, for those in
general use are really infinitely granular in com
position and Professor Lppmann spent little
time in experimenting before he could obtain
one sufficiently perfect for his purpose That.
however. he accomplished by introducing larg-
er proportion Of organic colloid, such as gela-
tine or coodion, into the lateral Of a film as
it is ordinarily compounded. Bot what is ii that
produces the color? 1t only be seen. we
have said. by reflected light In fact the colors
are due to what is called Interference, and
are of the same kind those reflected by a
soap bubble or by mother of pearl. When a ray
of ordinary light-which really is compounded Of
spectrum-falls upon a service which is inter-
rupted by irregularities of the right character,
this is as it were. broken into spray. and the
waves Of each kind Of light interfere that the
balance which produces the sensation of white
ness is disturbed. and colors visible. The
most striking fact now brought out is that when
a wave of light of any kind is reflected back
from the mirror through the film during ex-
posture it produces mechanical effect on this
sets II thrOhbing in harmony with its vibrations
and these thrills remain impressed upon the sur
face. Hence. when light is allowed to fall on
the film III the proper direction, and is reflected
from it, that surface produces interference. -
and this is such exhibit to the eye the
identical colors which produced at the outset the
vibration in the film. Even II this wonderful
discovery does not lead 20 the achievement Of
actual color photogra ply. Ii is certain TO be
fruitful in other results of scientific value