Morning journal and courier., 1889-10-10
photo~ranbfnr CoIors.

Captain W. dew. Abney, in a paper on
the effect Of light on matter read before the
British association, said: "Ths question is
often asked when photography in natural
colors will be discovered. Photography in
natural colors not only has been discovered,
but pictures in natural colors have been pro-
duced. I am not alluding to the pictures
produced by manual work, and which have
from time to time been foisted on a credu-
lous public as being produced by the action
of light itself, much to the damage of pho
tography and usually to the so called inven-
tors. Roughly speaking, the method of pro-
ducing the spectrum in it's natural colors is
to chlorinizs silver plate, expose it to white
light till it assumes violet color, heat till it
becomes rather ruddy, and expose it to q
bright spectrum. The spestrum colors are
then impressed in their natural tints. Ex-
pertinent has shown that these colors are due
to an oxidized product being formed at the
red end of the spectrum and q reduced pro-
duct at the violet end. Photography in nat
ural colors, however, is only interesting from
a scientific point of view, and, so far as I
can see, can never have commercial value.
"a process to be useful must be one by
which reproductions are strictly made; in
other words, it must be developing and not
q printing process, and it must be taken in
the camera, for any printing process requires
not only bright light, but also prolonged
exposure Now it can be conceived that in
a substance which absorbs all the visible
spectrum, the molecules can be 80 shaken
and sifted by the different rays that eventu-
ally they sort themselves into masses which
reflect the particular rays by which they are
shaken; but it is almost might say quite
impossible to believe that when this sift-
ing has only been commenced, as it would
be in the short exposure to which a camera
picture is submitted, the substance deposited
to build up the image by purely chemical
means would be 80 obliging az to deposit in
that the particular size of particle which
should give to the image the color Of the
nucleus on which it was dspositing. I am
aware that in the early days of photography
we heard goood deal about curious results
that had been obtained in negatives. where
red brick houses were shown as red and the
blue sky as blush. The cause of these few
condolences is not hard to explain, and
would be exactly the same as when the red
brick houses were shown as blush and the
sky as red in a negative. The records OF the
production of the latter negatives are natu-
rally not abundant, since they would not at
tract much attention. I may repeat then
that photography in natural colors by a
printing out prccess-by which l mean by
the action OF light alone-is not only possi-
BILE, but has bsen done, but that the produc-
ton of negative in natural colors from
which prints IN natural colors might be pro-
duced appears, in the present state of our
knowledge, to be impossible. Supposing 1t
were not impraeticable, it would be unsatis>
faetory, as the light with which the picture
was impressed would be very different from
that In which 1t would be viewed.
"Artists are fully aware of this difficulty
in painting, and taking their precautions
against it. The nearest approach to success
In producing colored pictures by light alone
is the method of taking three negatives of
the same subject through different oolored
glasses, complimentary to the three color
sensations which together give to the eye the
sensations Of white light. The method is
open to objection on account of the impure
color of the glasses used. If a device could
be adopted whereby only those three parts of
the spectrum could be severally used which
form the color sensations, the method would
be more perfect than it is at present. Even
then perfection could not be attained, owing
to defect which is inherent in photography
and which cannot be eliminated. This de-
feet is the imperfect representation Of grada-
tion of tone. For instance, If we have a
strip graduated from what we call black to
white lit must be recollected that no tone can
scientifically be called black and none white)
and photograph 1t, We shall find that In
print from the negative the darkness which
Is supposed to represent gray OF eaual NIX
lures Of black and white by no means ooes
40 unless the black is not as black nor the
white as white as the original"