[Footnote 1: Read before the Photographic Association of
Brooklyn.]
By OSCAR O. LITZKOW.
What I want to show is the manner in which the process has been
tested. My employer, Mr. Bierstadt, has given me permission to show
you some samples, and also his chart containing the spectrum colors:
violet, indigo blue, green, yellow, orange, red, and black. This chart
has been photographed in the orthochromatic and also in the ordinary
way.
There are many ways of producing an orthochromatic effect; one is the
use of a glass tank placed behind or in front of the lens, in which a
coloring matter from either a vegetable or mineral product is placed;
this tank or cell is, however, only for use in the studio, as for
outdoor photography we have a colored glass screen, so as not to be
bothered with carrying colored solution.
The tank is constructed as follows: Procure two pieces of best white
plate glass, about 6 inches square; between these place a piece of
rubber of the same size square, and about 3/8 of an inch thick. In the
center of this rubber cut out a circle about 4 inches diameter, and
from one of the corners to the center of the circle cut out a narrow
strip ¼ inch wide; this serves as the mouth of the tank. The two
pieces of glass and the rubber are cemented together with rubber
cement; then, to hold it firmly together, two brass flanges are used
as a clamp, with four screws at an equal distance apart; a thin sheet
of rubber is on the glass side of the flanges to prevent direct
contact with the glass, the center remaining clear for the rays of
light to pass through solution and glass.
One of the best orthochromatic effects made through this tank is with
a three-grains-to-the-ounce solution of bichromatic of ammonia or
bichromate of potassium. In this method there is no preparation used
on the plate. A common rapid dry plate is exposed through this
solution; the exposure, however, is about twenty times longer than it
would be if you removed the tank with the yellow solution, or, in
other words, if a dry-plate is exposed one minute without the yellow
solution it would have to be exposed twenty minutes through a
three-grain solution of bichromate of potassium or ammonia. It
produces wonderful results on an oil painting or any highly colored
object.
Another method, and the one best adapted for landscapes, is to bathe
the plate in erythrosine and then expose it through a yellow glass
screen.
As an illustration, suppose we have before us a beautiful landscape.
In the foreground beautiful foliage, in the center a lake, in the
distance hills, with a bluish haze appearing pleasing to the eye, also
a nice sky with light clouds. Now make a plain negative, and see what
has become of your clouds, hills, and the distance--not visible! Some
photographers have been led to think that by underexposing they retain
the distance, but they sacrifice the foreground; besides, it does not
produce an orthochromatic effect.
But it is a good idea to expose longer on the foreground than you do
on the distance. This can be done by raising the cap of the lens
skyward and gradually shut off, giving the foreground more exposure.
Plates are prepared for orthochromatic work as follows: Take any
ordinary rapid dry plate, place it in a bath containing
Distilled water 200 c.c.
Strong liquid ammonia 2 c.c.
Rock it for two minutes, work as dark as you possibly can. Now take it
out, and place it in the second bath for one and one-fourth minutes
and keep it rocking. Have on hand for use a stock solution of
Distilled water 1,000 parts.
Erythrosine "Y" brand 1 part.
Prepare second bath as follows:
Erythrosine stock solution 25 c.c.
Distilled water 175 c.c.
Strong water ammonia 4 c.c.
After removing the plate, dip it again face down to rinse off any
particles of scum, etc., that may get in the bath accidentally. This
bath may be used for one dozen 8 by 10, when it should be thrown away
and fresh bath used.
After the plates come out of the last bath, they should be stood on
clean blotting paper to absorb the excess of solution. I would also
advise to use clean fingers. Pyro. or hypo. on the fingers is a
drawback to success.
After plates have been drained, place them in a cleaned rack in an
absolutely light-tight closet, with air holes so constructed as to
admit air but no light; the plates will dry in from eight to twelve
hours. They are best prepared in the evening, and, if the closet is
good, will be dry in the morning.
After the plates are dry they may be packed face to face with nothing
between them, in a double-cover paper box, and put in a dark closet
free from sulphureted hydrogen gas, until ready for use. I have kept
plates for three months in this way, and they were in good condition.
Great care should be used in developing these plates, as they are
sensitive to the red; get used to developing in a dark part of the
dark room; occasionally you may look at the process of development in
a little stronger light.
The exposure through the yellow screen with an erythrosine plate is
about the same as if you had no orthochromatic plate--a plain plate
instead--provided you are not using too dark a yellow on your screen.
This can only be determined by experience. I will give to a common
plate about four seconds, an orthochromatic plate under the same
conditions five seconds.
The yellow glass screen is prepared as follows: Take a piece of best
plate glass--common cannot be used--clean it nicely; take another
large plate glass, or anything that is level and true, level it with a
small spirit-level. Now take the cleaned piece of glass and coat it
with