New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1891-05-31
A PHOTOGRAPH OF COLORS SHogM
THE ONLY PLATE OF THE KIND IN THE coUN
TRY. EXHIBITED IN BROOKLYN.

TRY. EXHIBITED IN BROOKLYN.
Among the most interesting features OF the Amerf'
can Photographic Conference which was neld ast week
was the exhibition on Wednesday night at the Criterion
in Brooklyn OF the plato on which Professor Lippmann
of Paris photographed the colors OF the spectrum
This plate was given by the Professor to Frank La
Mama, president Of the Brooklyn Academy of Photog
raphy who is now in Paris, and IS the only one Of
the kind which has passed from the Professors pos
session. Mr. La Mamma, in a letter sent win the
plate describes the process Of making IL as follows:
The image Of the spectrum now shown is direct
positive and is obtained by processes as beautifully
simple they scientifically exact beam from an
electric arc light n OF % amperes) passes
successfully through condenser. water bath to dvest
IL OF heat rays direct vision prism with slit Of about
millImeters lens reducing the system TO parallel
rays double lens reduce the image, and the
spectrum then focused average intensity OF color
upon the usual ground glass. The film which is TO re-
ceive the image be structureess and senstized
uniformly that IL must be transparent, or at least only
slightly opaescen and free from the granny texture Of the
usual commercial emusons The ordinary wet plate well
washed fulns conditions Professor Lippmann has
experimental successfully with geatine albumen and
collodon films and either iodde or bromide Of silver
sensltlzers.
The plate is placed film side in against shaped
piece of rubber piece of ordinary glass is placed aagnst
the other side Of this U, and the three firmly camped
together making sort OF trough two more minimetres
through, which is filled with quicksilver, the film and the
substituted for the ground glass in the camera the sensitive
film In the plane OF focus sufficient exposure
given and the plate developed in the usual manner The
brightness OF the coors depends in great measure on the
the silver deposit These colOrs do not appear
until after the plate is dry
Needless to say operations carried by
safe light the electric light contained in light tight
box from which the beam through shutter door
when needed. This particular specimen albumenised
coodion hm sensZed In 10 cent nitrate OF silver
solution the entire field Of the spectrum exposed for three
minutes without any interposng color screen; total dis
lance from light to plate about metre. 1t de-
veoped with pyrogac acid and sesqucarbonae OF soda
until the entire surface Of the spectrum well brought
out which required about 1--WE minutes Time
hypo solution very carefully and thoroughly washed and
the exquisty beautiful band coors before
you.
The principle Of It's production is explained by Pro-
fessor Lippmann follows: During exposure the beam
Of light has passed through the glass supporting the film,
through tho transparent film itself and then reflected from
the surface Of mercury in contact back through the m
reflected rays collding. 1 may express it, with
Incident rays and forming frnges Of Interference that
is points within the film where both incident
reflected rays in the phase direction OF viba-
ton maximum effect OF light is produced; per
contra, where the rays are in opposite phases
vibration Is annuled, obscurty results and there
Is absence of effect the result develop
is series OF infinitely thin lamnae strata. with
planes parallel the surface OF the m each in thickness
half length OF the color which produced them and
this distance apart from the other In film say
one-tweneth OF mlimeter thick he 500th Of nch),
over $50 such layers ray from
the yellow $50 the violet The coors therefore
pigments; they but the decomposition Of the
white light by which the plate Il viewed ard analogous
to the play Of color upon bubble the rdescence
Of mother Of pearl, but purer and brilliant
providing that development has produced highly rejecting
white layers silver and necessarily the greater the
number Of rejecting layers the richer will the reflected
eolors appear.
Whether this discovery viii lead to the eventual repro
ducton OF natures reflected from sunset skies
many hued flowers whether with and chemicals we
shall ever fix upon tho sensitlzed film madens blush or
the Gorgeous OF autumn leaves, can only be known
after continued and reasoned experiment, but the Ette
plate before you asserts beyond dispute that the h
obstacles in this direction been successfully removed
by Professor Lippmann.