The times. (Owosso, Mich.) 1882-1897, 1889-11-22
PHOTOGRAPHIC coLoRs.
II Can be Done, but h not Generally
Understood, as II Has no Great Value.

~ Can Dc Done, out ~ not Generally
Understood. as 1t Has no Great Value.
Capt. w. de w. Abney, in a paper
on the effect of light on matter read
before the British association, said:
The question is often asked when pho
Biography in natural colors will be dis
covered. Photography in natural
colors not only has been discovered,
but pictures in natural colors have
been produced. am not abiding to
the pictures produced by manual
work, and which have from time to
time been foisted on a credulous pub
lie as being produced by the action of
light itself, much to the damage of
photography and usually to the so
called inventors. Roughly speaking,
the method of producing the spectrum
in its natural colors is to chlorinize a
silver plate, expose it to white light
till it assumes violet color, heat till
it becomes rather ruddy, and expose
it to a bright spectrum. The spectrum
colors are then impressed in their nat
ural tints. Experiment has shown
that these colors are due to an oxidized
product being formed at the red end of
the spectrum and a reduced product at
the violet end. Photography in natu-
raj colors, however, is only interest
ing from a scientific point of view,
and, so far as can see, can never have
a commercial value.
A process to be useful must be one
by which reproductions are strictly
made; in other words, it must be de-
veloping and not printing process,
and it must be taken in the camera,
for any printing process requires not
only bright light, but also pro-
longed exposure. Now, it can be con-
ceived that in a substance which alb
serbs all the visible spectrum, the mol
ecules can be SO shaken and sifted by
the different rays that eventually they
sort themselves into masses which re
fleet the particular rays by which they
are shaken; but it is almost-I might
say quite-impossible to believe that
when this sitting has only been COM
menced, as it would be in the short ex-
posture to which a camera picture is
submitted, the substance deposited to
build up the image by purely chemi-
cal means would be SO obliging as to
deposit in that the particular size Of par
ticle which should give to the image
the color of the nucleus on which it
was depositing. I am aware that in
the early days of photography we
heard O good deal about curious re-
suits that had been obtained in mega
tives, where red brick houses were
shown as red and the blue sky as blu
ish. The cause of these 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 naturally not abundant,
since they would not attract much at
tention. may repeat then that pho
Biography in natural colors by print.
ing out process-by which l mean by
the action of light alone-is not only
possible, but has been done; that
the production of negative in natu-
raj colors might be produced appears,
in the present state of our knowledge,
to be impossible. Surprising it were
not impracticable, it would be unsatis-
factory, as the light with which the
picture was impressed would DO very
different from that in which it would
be viewed.
Artists are fully aware of this diff
Guilty in painting, and take their pre-
cautions against it. The nearest APP
proach to success in producing pic
lures by light alone is the method of
taking three negatives of the same
subject through different colored
glasses, complementary to the three
color sensations which together give
to the eye the sensations of white
light. The method is opened to OBJ
lection on account of the impure color
of the glasses used. If device could
be adopted whereby only those three
parts of the spectrum could be sever
ally used which form the color sensa-
tons, the method would be more per-
feet than it is at present. Even then
perfection could not be attained, ow-
ing to a defect which is inherent in
photography and which cannot be
eliminated. This defect is the imperfect
representation of graduation of tone.
For instance, if we have q strip gradu-
ated from what we call black to white
Git must be recollected that no tone
can scientifically be called black and
none white) and photograph it, we
find that in print from the negative
the darkness which is supposed to rep
resent gray of equal mixtures of
black and white by no means does so
unless the black is not as black nor the
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