El Paso herald. (El Paso, Tex.) 1901-1931, 1911-07-06

Il NE Oh the most interesting and at
8 the same time most battling
lines of research In which the
scientists of today are engaged is the
problem Of finding a process whereby
the true color values Of nature may
be captured with q camera, and made
a matter Of Photographic record. When
the principle of the photograp hic cam
era was discovered scientists thought
it would be but a short step from the
registration of light and shadow on
plates to the correct reproduction Of
colOrs.
Experiments in that direction were
begun a century ago, when Seebeck
obtained his first color Impressions
upon a paper impregnated with moist
silver chloride. But although various
processes have been discovered which
enable the photographer to catch some
of the colors of an object, the attain
ment of the perfect reproduction Of
color in a photograph seems as dis
tant today as when Seebeck made his
experiment 100 years ago.
Potatoes for ColOrIng.
What progress has been made is
based largely upon the plebian potato.
1t is with the starch of this humble
member of the vegetable kingdom that
the plates are prepared upon which the
elusive rays of light are to be cap
tured in the making of color mega
tive. The starch used has been ground
so fine that a single five-by-seyen inch
plate will contain as many as $4,000
600 grains.
These starch grains are divided into
three lots, and each lot is dyed, one
orange, another green and the third
violet These colored grains are then
distributed at random over plate COW
cred with a sticky transparent prepa-
ration. The spaces between the grains
of starch are filed with finely pow
dered charcoal. Another plate is then
placed over this mass and pressed
against the first one. This process
brushes every grain of starch, and
the result is a sort, of tri-colored mo-
sale made up of powdered starch
When the plate is exposed, green rays
Of light pass through the green starch
violet rays through the violet starch,
and orange rays through the orange
starch In this way all other colors
but green are filtered out OF the Pic
ture at the place where the greeR
ought to appear. and likewise in the
case OF the violet and the orange.
Do Not Reproduce All COlOrs.
AS stated before. the photographs
made by this color process do not re-
produce all of the colors possessed by
represent Only the principal colors
may be transferred. In the eye. ma
ture still possesses the only photo
graphic plate which is able earrectly
to register the value OF all light rays
The aim Of men who are experiment
ing in color photography is TO produce
a Photographic plate which will du-
plicate the work Of the painter with
out involving the long and tedious
In
value Of the present sort of color pho
Biography is to furnish a key to cor
rect coloring for the printer. Form
erly, when a seed establishment for
instance. wanted to portray Its fruits
and vegetables in their natural colors.
It was necessary to engage an artist
to paint the picture of each vegetable
and fruit to be Illustrated, his Work
to be followed by that of the en-
graver or photographer Today he may
make a picture upon color plate. and
rid himself of the major portion OK
the expense Of preparing his SEED
catalog.
There are many processes of color
photography in use today, each anord-
ing a considerable range for the sre-
production Of colors. and each possess
ing certain advantages over other pre-
cesses. but rome of them as vet mas
item necessary to successful color pho
tography-a Photographic paper which
is able to receive satisfactorily the
color Impression. There are many in
vestigators who declare that such a
paper cannot be made.
Based on Light Rays.
Color photography is based upon the
accepted theories Of light rays. II
has long been known that ray OF
light passing through a prism, the
simplest form of a spectroscope, is
broken up into the colors of the rain
bow Not only is the scientist able
to analyze a light ray as the chemist
analyses a chemical compound. but he
is able to build 1t up again. This
can readily be Illustrated with three
pieces of colored glass. If one takes
and one blue violet, and puts them all
together. the light passing through
them will be white Taking any two
of the three pieces he may make still
different colored lights.
Another property of light which has
its bearings upon color photography is
the fact that it consists of waves of
varying lengths. Scientists have been
able TO devise measuring machines
which can measure a distance much
shorter than the millionth part OF an
inch. With these instruments they
have been able to measure the length
of the light rays which make the diff
ferent colors.
Mercury Sometimes Used.
In one of the processes of color
photography a glass plate Is covered