The Daily Missoulian., 1911-07-06

research In whivh the scientists of to-
day are engaged Is the problem Of find
ing process whereby the true color
values OF nature may be captured with
camera and made a matter of photo
g.'aphic record When the principle
of the Photographic camera was dis i
covered scientists thought 1t would be
but II short step from the registration
OF light and shadow on plates to the
correct reproduction of colors.
Experiments IN that direction were
begun century ago, when Seebeck k
obtained his first color Impressions up
on u 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 distant
today as when Setback made his ex-
pertinent a hundred years ago.
What progress has been made IL
Dhsed largely upon the nebian potato.
IL liz 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 can
tured In making OF n color negative.
The starch used has been ground so
fine that single five -by-seven inch
plate Will contain as many as 1856, 900. :
900 grains.
These starch grains are divided in
to three lots. and each lot Is dyed. one
orange, another green and tho third
violet These colored grains are then
distributed AT random over n plate
covered with sticky transparent
preparation The spaces between the
grains of starch are filled with finely
powdered charcoal Another plate Is
then placed over this mess and pressed
against the first one. This process
crushes every grain ..r starch, and the
result Is "A sort of tri-colored mosaic
made up of powdered starch. When
the plate II 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 picture at the
place where the green ought to appear,
ana likewise In the case of the violet
and the orange.
AZ stated before. the Photographs
made by this color process do not re-
produce all of the colors possessed by
any many -coiored object which they
represent. Only the principle colors
may be transferred. In the eye, nature
still possesses the only Photographic
plate which IL able correctly to register
the value of all ligh, rays.
The aim of the men who are cy-
perlmenting In color photography Is
to produce a Photographic plate which
VIII duplicate the work of the painter
without involving the long and tedious
processes he must employ. The main
value of the present sort of color
photography Is to furnish a key to
correct coloring for the printer. Form
erly when a seed establishment, for in
stance. wanted to portray its fruits
and vegetables In their natural colors
1t 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 engraver
or photographer. Today he may make
picture upon II plate. and rid himself
of the major portion of the expense
of preparing his seed catalogue.
There are many processes of color
photography In use today. each afford
Ing a considerable range for the repro :
duction of colors. and each possessing
certain advantages over other pro-
cesses, but none of them as yet has
been able to offer the most essential
item necessary to successful color pho
tography-a Photographic paper which
In able to receive satisfactorily the
color impression There are many in
vestigators who declare that such n
paper cannot be made
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 n spectr0scopc, Is broken up
into the colors of the rainbow Not
only is the scientist able to analyize
n light ray as the chemist analyses
n chemical compound. hut he is able
to build II up again. This can readily
be illustrated with three pieces of col
ored glass, II one takes these three
pieces, one red, one green 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 II 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.
In one of the processes of color pho
Biography glass plate Is covered with
an emulsion perfectly transparent and
exposed In the cameras with the glass
side to the lens. and with the film
side backed Up with mercury. In this
way the brilliant mirror of mercury
comes In close contact with the film
and reflects back upon itself the light
which comes from the lens. The film
must be transparent and thick enough
for one or two of the longest light
waves to be fully formed within il,
Where the light waves collide there
will be no image: where they do not
come together an image will appear,
Tho ract,lt ar tbis g that ,yhan Mat a