Evening star. [volume] (Washington, D.C.) 1854-1972, 1930-05-25
GHOST PICTURES
TAKEN |NDARKNESS
Scientist Believes Classes Ex'
plain Weird Photographs
of Butterflies.
BY THOMAS r. HENRY.

Experiments with ghost" pictures
photographs Of dead butterflies taken
In complete darkness by means of en-
anations of some sort from the crea-
lures themselves which affect the plate
In much the same way rs light-are
being made by DR.. Austin H. Clark of
the Smithsonian Institution.
The pressed butterfly, he explains, Is
placed on a fiat surface and the plate
laid upon it. The whole then is in
closed in a box from which all light is
excluded. After from "a hours to a
week the plate is removed. and devel-
oped, and prints taken from it show all
the details of the wing markings.
The method succeeds even with but
terflies that have been dead for 80
years. With fresh specimens the process
Is much more rapid. The image is not
an imprint caused by pressure on the
plate, since it is brought out only when
the plate is developed. apparently does
not vary entirely in proportion to pres
sure differences, and there Is a fine
differentiation of values between diff
ferent shades of wing color.
Believes Gases Responsible.
This weird phenomenon, Clark says.
probably is due to obscure gases Of
some sort, chemical products of the
wing composition, which continue to
escape in minute quantities indefinitely
after the insect is dead, the rate Of
emanation being affected by the pig
ment through which it must pass.
These gasses-there apparently are sew
eral. varying with species and pigment
in some way liberate the bromine OF the
III, II -. Nf kI@A 1HfA
with which the plate is covered. Thus
they accomplish almost exactly the
same result as light.
The one other possibility, he believes,
IL that the wings may send out ex-
tremely short, invisible ultra violet light
rays which effect the plate, but this is
unlikely.
DR.. Clark's work is believed to be
the first attempt to take actual ghost"
pictures of dead creatures in this coun-
try. but similar experiments with
charred paper were conducted several
years ago at the Bureau of Standards
photographic laboratory for the Post
ONCE Department in an effort to devise
q technique for obtaining the text Of
burned documents which had not been
reduced to ashes. Papers which had
been subjected to intense heat so that
they were only black sheets of carbon
from which traces Of letters had dis
appeared were placed underneath pre-
pared plates and kept in complete dark
ness. When the plates were developed
the original writing appeared in white
on a black background. The expert
menter, Raymond Davis, then advanced
the explanation that the effect was due
to the freeing of the bromide by the
action of some obscure gas escaping
from the paper. Ink in the texture of
the paper apparently greatly reduced
the rate at which this gas escaped, so
that no impression was made of those
parts of the paper which had con-
tanned the pen strokes. Hence the latter
appeared in white.
Effect on Films Opposite.
The effect on films, Davis found, was
exactly the opposite. With the charred
paper 1t required two months TO secure
developed the letters appeared black
and the background white. The same
was found by Clark with the butterflies,
the pictures requiring long exposure
and coming out badly. Apparently, the
pigment-either ink or the natural color
OF the wtng-accelerates another kind
of gas which affects the chemical COM
position OF film, but not of plate.
In the wei inesS Of the effect, DR..
fSDNAAeS
gestive of some bit of life which has
not escaped with the death of the or
ganism, although this mystical con-
clusion Is not warranted in scientific
consideration of the results.
The Photographic work was done by
DR.. Clark's son. Austin j. B. Clark,
under his fathers direction. They
worked with % varieties of butterflies.
finding different positive and negative
effects varying with the nature Of the
pigment.
After a great many pictures have
been taken, Clark explained, enough
may be learned of the behavior of these
ghost" gases for organic chemists to
isolate them and determine their ma
ture. Their evident extremely compile
Gated nature, however, places this a
long way in the future, he believes. Re-
CARELESS of the significance of the phe-
nomenon in the science of photography.
he points out, it may open un a. new
avenue in the study Of the nature of
organic matter. A number of tests of
the same nature, he explained. have
been made in German laboratories.