Page 124 - The Wellington photographic handbook

may be hinged to the opening with a piece of cloth, and a button
or spring fitted to keep the door closed when required, and the
frame is complete. To use this, the back is taken out and the
negative laid on the glass and shifted about until the exact part from
which the slide is to be made is seen to occupy the desired position
in the opening left in the black paper. The solid back of the frame
is then put in, and fastened with the ordinary springs of the frame.
The lantern plate can then be dropped in the opening in the back
with the certainty that it will fall exactly where it is wanted, and
without any risk of scratching the negative. If two or more slides
are wanted from the same negative they can be made with one
adjustment.
EXPOSURE.

The exposure necessary depends, of course, upon the strength
of the light used and the density and colour of the negative. As a
rough guide, using the WELLINGTON Lantern Plates, three
seconds at three feet from a 16 c.p. lamp will be found approxi-
mately correct for average negatives. v
LANTERN SLIDES BY REDUCTION.
Before proceeding to describe the development of lantern
plates, it is well to say something about making slides by reduction,
because, although the process is very different from the contact
method just described, the development and after processes are
the same, the difference being in the matter of exposure only.
The simplest method of making slides by reduction is by means
of a fixed-focus reducing camera. This has a holder at one end to
take the negative, and another at the other end to take the lantern
plate. Between the two is a lens. The whole arrangement is so fixed
that the image of the whole of the negative is sharply focussed on
the lantern plate of the required size. The camera, in the simpler
forms, is taken bodily into the dark-room for the insertion of the
plate, and is then carried out and stood on end in the open air so
that the uninterrupted light of the sky may shine straight down
through the negative. Needless to say, direct sunlight should be
avoided. After an exposure, regarding the length of which no
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