The times. [volume] (Richmond, Va.) 1890-1903, 1900-07-31
PHOTOGRAPHY in
DIVERSE COLORS
A Process Which Science Has Yet
to Make Practicable.
TOO COSTLY AND LABORI0Us.
a Seeing Machine, Which Produces
the Effect of Perfect Color Pho
tosraphy-Thc Method In
vented by Frcnchman.
TOO COSTLY AND LABoRI0US.

About once in two or three years some
one processes TO have solved the problem
OF color photography: but the Photographic
world doesn't become wiyly excited over
these assertions, as 1t did formerly LOO
many of the processes have proved 10 DE
fake. pure and simple, and those founded
upon scientific truth have been only modl-
Gcations OF earlier discoveries
Color photography has been a fascinating
problem for scientists ever since the carry
part of this century. In 1910 PROT See
beck, of Jena. made some Interesting eN-
perimeHts III the reproduction OF lic
natural colors of the spectrum. ana a most
OF scientists followed his lead Becquerei
IN 1873 succeeded in reproducing all OF lts
hues Of the spectrum upon plate covered
with film of violet subchloride OF sill
yer, and even photographed various Cd
jects In their natural colors. but found 10
way Of fixing these tiuts so that they "ohid
stand exposure to the light. Other men
experimental and obtained varying results
by modified chemical process, but the IN
stability of color baffled them as it had
batiied Becquerel.
II was one thing TO understand TINT
rnurtate Of silver, through reflection and
Interference of light rays among It's par
;icles, would take the colors of the spec
trurn, and quite another thing to fix these
coiors permanently when they mad been
obtained Many scientists have abandoned
the idea that a direct photography in
color with resulting permanent and salts
factory prints. will ever he obtained.
Others. more optimistic, insist that the
thing is a possibility, even though q re-
mole one In the meantime what develop
ment does occur lies along one or two
lines. either being based upon the trich-
r,omatic theory of vision. and composite
photography, or following L'ppnan's in
Preferential method, founded upon the
snw of wave vibration in light.
LIPPMAN'S DISCOVERIES.
Iippnan's discoveries in color photogra-
ply were really the last to stir up any
great excitement among scientists. NJ.
1Ippman was a Professor of Physics in
the Sorbonne. with no practical knowledge
of photography. Not even the kodak
mania had marked him for its own; but
he knew u thing two about abstract
physics, and in the course OF lectures to
young France on the subject Of acoustics
and the neutralizing of sound by the meet
ing of advancing and reflected sound
waves. it occurred to him that the same
theories applied to color would produce
color photographs.
He turned TO photography and demon
e,rated his theory II his own satisfaction
and the editication Of the scientific world
but ha never attempted 10 make CONNER
cfsl profit OF his discovery. and went on Sc
-enely lecturing upon abstract physics. The
results he obtained are what might be eX-
pected Of so theoretical a scientist. He
unquestionably accomplished the nearest
thing to pure color photography that has
been achieved. and he vindcated his theory.
but any practical application of his meth
DDS 10 general purposes Is out Of the ques
ton. The process is complicated and diff
cult and multiplication Of the photographs
af- Sc ir1lrlDSSihla few ir0nTnSSnIlS
wore made by his method and these few
with great expenditure of time, work and
money.
The success Of this method depended upon
the same principle that explained tlla re-
production OF color IN ;nuriate Of silver
ths Interference OF light waves through re-
fection. IJppman put a transparent, high
o. sensitiZed finn in Immediate contact
witllza mirror backed with mercury. Light
passing through the film was reflected
Back along the same line by the mirror.
Advancing light wave: and rejecting l:ght
waves, meeting under certain conditions,
cancel or neut1aliZe ona another, tho re-
suit being white Eight minus these can
celled waves-that is coiored light Color
waves differ in wave length according TO
tho different lines of the spectrum so the
conditions under which tbs direct and re-
fiectei waves meet vary according 10 their
color, and The fin records this variance
The white light entering the camera has
been separated into its component parts
pure white light being composed OF all
the hues of the spectrum-ani. when the
film is again exposed TO white light, il
shows the Impression received in colcrs.
One great disadvantage OF these Lppman
photographs is that the white light must
fail upon the completed film ut q certain
angle in order 10 give the color effect.
Seen at any other angle The photographs
look like coloricss negatives.
INDIRECT METHODS
TIE only practical success in color pho
Biography so far has been accomplished by
Indirect methods: and. though these pro-
cesses may not he so interesting from the
viewpoint Of abstract science as the ILipp-
snnn process, their commercial value is
Infinitely greater Indirect color photog-
raphy primarily consists in the produc-
ton of three separate negatives, taken
through screens Of the three primary col
nrs. red. green and blue, and in the ppti-
raj superpositfon of these images: but there
have been innumerahle developments of
this process. The original composite color
photography. requiring three separate
negatives obtained by three separate eN-
posures and three separate positves pro-
5ected by a single lantern, was too cum
hersome and complicated 10 he practicable.
A great effort has been made to bring the
process into such shape that II could be
easily accomplished even by the amnteur
and the apparatus required for 1t carried
as easily as the ordinary camera
No such conditions have been attained.
hut a good deal has been accomplished.
and the photochromoscope, with its more
recent developments, the kromskop, IS
thought by scientists to come as near a
solution of the problem as any OF the later
Inventions
BY this photochromoscope process the
three negatives are taken upon q single
sensitive plate al one exposure and the
contact positive. cut into three sections
with scissors and mounted upon a folding
cardboard, is dropped into the photochro-
mosc"2e, which, as we'll as the camera
NAV be made stereoscofsc. the size Of the
ordinary hand stereoscope The camera
eliminates three colorless transparent
positiTes separately by lights of the three
primary tlnts and these impressions are
OFFICIALLY recombined into one colore7
image IN the seeing apparatus or photo
chromoscone. OF course. this seeing instru-
naent is necessary to carry out the sense
o. Color, so the process Is far from being
the one long desired. which is TO produce
colored prints that may be framed and
hung on the wall. Through this viewing