ENLARGING AT HOME—DAYLIGHT
For many pictorial and decorative purposes the amateur will experience
the need of a simple method of producing large pictures from his small
negatives. This brings us to enlarging on bromide paper as among the
things which may be easily and profitably done at home by daylight
or artificial light. For daylight enlarging no special apparatus is
needed, beyond the camera and lens used to make the original negative,
and a couple of large trays for the development and fixing of the
enlargement. Presuming that we do not intend an enlargement larger than
10 x 12 inches, these latter may be of vulcanite or japanned tin, and
inexpensive.
To begin we require a small room to ourselves, with a window facing
north, and giving us an unobstructed view of the sky. This window we
make absolutely dark by fitting to it a light wooden framework covered
with black cloth, or two thicknesses of brown paper. The room is now
quite dark, and we must work by gaslight until we are ready to enlarge.
In the window shutter, at a convenient height, we cut an opening
exactly the size of the negative to be enlarged. At the two sides and
bottom of this opening we glue three wooden laths, and fasten a drawing
pin in each, so that we can slide our negative in, upside down, and it
will be held close to the opening. The film side of the negative must
always face the back of the lens. Outside the window we place a sheet
of white cardboard, or a mirror, at an angle of 45°, so that it will
help us to throw as much light as possible through the negative at the
opening in the shutter.
Returning indoors, we place a long table with one end close up to the
window, and on it place a box of such a size that, when we place our
camera on the box with the lens pointing into the room, the back of
the camera (ground-glass removed) exactly covers the frame enclosing
our negative. The light reflected by the cardboard outside now streams
into the room, passing through the negative, camera, and lens. At the
other end of the table we place a box on its end, and take care that
it shall be perfectly upright. To the front of this box, facing the
lens, we pin a sheet of white paper measuring about 11 x 14 inches. The
image of the negative in the window appears (upright) upon this white
screen. By moving the box nearer to or farther away from the lens we
get the enlarged image of the desired size, 10 x 12 inches, but it is
not sharp, _i.e._, its details are not clearly and distinctly defined.
By means of the focusing front of the camera, or by moving the box a
little back or forward, we gradually get the enlarged picture of the
right size and perfectly sharp; in other words we focus it correctly.
The brightness or illumination of the image depends upon the intensity
of the light outdoors, and the diaphragm used in the lens. We must use
as large a diaphragm as we dare, consistent with the desired degree of
sharpness in the picture. If the image is not equally sharp all over,
we must see whether the front of the box carrying the sheet of paper is
perfectly parallel with the negative. This is essential. Another detail
to be looked after is to make sure that no light enters the room save
through the camera and lens. When we have got all these preliminaries
arranged to our satisfaction we are ready for the actual work of
enlarging on bromide paper, and from now on must work by the light of
our dark-room lamp.
What is bromide paper? It is simply paper coated with a sensitive
emulsion, exactly like that which, coated on glass, forms the sensitive
dry plate used in making negatives. The emulsion on bromide paper,
however, is much less rapid than that used in making plates. Thus we
must handle bromide paper with all the care used in handling sensitive
plates before exposure, and scrupulously keep it from white light
until it has been exposed, developed, and fixed. Its manipulation
is precisely similar to that employed in making negatives, but the
character of the support (white paper) indicates that we must be more
careful in the matter of cleanliness in our manipulation of paper than
with plates.
Covering the lens, and working by the dim red light of the dark-room
lamp, we open the package of bromide paper and take out a single sheet,
which we cut into strips one and a half inches in width and the full
length of the sheet. These we will use in making test exposures to
ascertain the correct exposure for our enlargement from the negative in
hand. To make a test, pin one of the strips to the cardboard or sheet
of paper on which the image was focused, in such a direction that it
includes part of the shadows in the picture. Now cover three-quarters
of the strip with a piece of brown or black paper and (supposing that
we have bright light outdoors, a negative of medium density, and stop
_f_/16 in the lens) give the quarter of the test strip an exposure of
one-half minute. Cap the lens, uncover another quarter of the strip,
and give it an exposure of another half minute. Repeat this operation
with the remaining two quarters of the test strip, and replace the cap
on the lens. We now have a strip which has received four different
exposures. The first quarter of the strip has had two minutes exposure;
the second quarter, one and a half minutes; the third, one minute;
and the fourth quarter, one-half minute. Upon developing this test
strip in the developer yet to be given, we will be able to judge as to
the correct exposure required, to get a good enlargement. Very thin
negatives will sometimes require only ten to thirty seconds; negatives
of medium density from one-half to one and a half minutes; very dense
negatives from one and a half to several minutes; after a little
experience we will find ourselves able to judge the exposure required
by the appearance of the negative on the screen.
When once we have determined the correct exposure for an enlargement
from any particular negative, and have _also_ taken the _actinometer
time_ of the light by exposing our Wynne meter at the opening in the
window through which the light enters, we can obviate any difficulty in
making other daylight enlargements from this negative by marking on
the edge of the negative the exposure time and the actinometer time.
Thus suppose the time of correct exposure was fifteen seconds, and the
actinometer time was only six seconds, we mark the negative 15 _Ex_/6
Act. If we divide the correct exposure time by the actinometer time we
get two and one-half as the result. Then we know that, for all after
enlargements of the same size from that negative, on the same brand
of bromide paper, the exposure should be two and one-half times the
actinometer time. After a few negatives have been tested and noted in
this way we will be able to intelligently compare other negatives with
these tested ones and judge, approximately, of the exposure they will
require without the necessity for a special test with each and every
negative.
Having determined the correct exposure required by the negative in
hand, we return to the darkened room and pin upon the white card
opposite the lens a full sheet of bromide paper, uncover the lens, and
make the exposure. The lens is then covered, and the exposed print is
removed from its support, enclosed in a light-tight envelope or tube,
and taken into the dark-room for development.
It is agreed that next to ferrous oxalate (which we will not trouble
with) a combination of metol and hydroquinone gives the best developer
for bromide paper. An excellent formula, originated by Yellott, is as
follows: Dissolve 55 grains of metol and 55 grains of hydroquinone
in 40 ounces of water; add sodium sulphite, 2 ounces, and sodium
carbonate, 2 ounces. This forms a one-solution developer which may be
prepared some time before it is needed, and stored in 2-ounce bottles
carefully corked. Two ounces of this solution gives us a sufficient
quantity of developer for an enlargement not larger than 11 x 14
inches. Just before use the contents of one bottle should be diluted by
adding from two to four ounces of water, and three or four drops of a
ten per cent solution of potassium bromide. This developer can be used
repeatedly, but if it is used too often will give greenish-black tones.
Care must be used not to add too much potassium bromide; too little
will result in degraded whites, and the print will acquire a foggy
appearance; too much will give unsatisfactory tones. What we must seek
to obtain is a rich black tone, like that of a good platinotype print.
Amidol, citol, rodinal are other good developers for bromide paper.
To develop the enlargement, lay the print, face up, in an 11 x 14
tray and flood it with water for a few moments to prevent it curling;
pour off the water and with a steady, even motion, flow the diluted
developing solution over the whole of the print. In a few seconds the
image will appear and gradually increase in detail and density. As soon
as it reaches the desired strength, pour the developer off into an
empty bottle (labelled _Used Developer_), rinse the print in running
water and immerse it in the fixing bath. This latter should be freshly
made by dissolving sodium hyposulphite, 3 ounces, in water, 16 ounces.
In this the print should be quietly rocked for ten or twelve minutes,
after which it should be removed and thoroughly washed for an hour and
a half in running water.