Photography Product booklet

CHAPTER XXIX
Making Lantern Slides

Supe MAKING EssentiaLty Printinc oN GLass—LaNTERN
Prates—DEVELOPING A SLIDE—MASKING—BINDING A
Lantern SuipE—Sporrinc—SurpEs By ‘REDUCTION.

ANTERN slide making cannot be pursued successfully
A Mithowt a Tanecin for showing the slides, It is only by
actiial projection that we can test our work and make sure that
it is right, or else see its defects and learn to remedy them.
This applies to expert workers as well as to beginners : hence
we often read in exhibition rules that “ the slides will be judged
in the lantern.” This need not act as a deterrent, however,
since most photographic societies own a lantern, and many of
them notify their members that their slides can be tested in
it at certain times. Even those who live out in the country
away from any camera club will usually find that the clergy-
man or schoolmaster has a lantern which he is only too
pleased to lend, especially if he can hope in return to borrow
some slides of local interest to be shown in it.

Slide making is, in its essentials, printing from the negative.
The print is made on glass instead of on paper, and is seen.
by projection on to a screen instead of by reflection from its
surface ; but otherwise the two are identical. I have some-
times been asked why a negative itself cannot be used as a
lantern slide : the answer to which question is that it can, but
that in such a case the projected image will be a negative
instead of a positive—its light and shade will be reversed,
Moreover, for reasons into which it is not necessary to go here,
the negative, if good as a negative, would be poor as a slide !
the character which a good lantern slide should possess is
quite different,

Lantern plates, which can be obtained from any dealer,

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are glass plates that have been coated with an emulsion,
similar, in a broad sense, to that upon the plates and films we
use for negative work, but more similar to (in some cases
identical with) that upon bromide or gaslight paper. On such
plates lantern slides can be made in a printing frame in much
the same way as prints are made, provided always that the
negative is of suitable size. This is important. For conveni-
ence in showing, a standard size for lantern slides has been
fixed, which in this country is 3} x 3} inches. If we are to
print our negatives on plates of this size in a printing frame,
it is evident that the picture on the negative must not be
larger then this—in fact it must be smaller, to allow for what
is called masking and binding the slide.

If the picture on the negative is too large, slides can be
made from it by what is termed “ reduction.” In this case
the negative is fixed up and illuminated from behind, and is
then photographed with the camera, using a lantern plate
and focussing the image so as to bring it to the size required.
In distinction from this, the method of making lantern slides
by printing in a printing frame is called “slide making by
contact.” It is this latter method, as the simpler, which will
be here described.

Lantern plates are obtainable in several kinds, but there
are two principal classes—" slow ”’ or plates for warm tones,
and “ fast” or plates for cold tones. Either kind will give
a fine black tone at will ; but for brown, purple, or red images
the slow plates must be used, When Slides are being made
by contact, the necessary exposures are so short that it is
immaterial’ whether fast or slow plates are used. Probably
the beginner will do well, if his dealer stocks both kinds, to
get a box of a slow variety by one of the standard makers,
and to start by getting black tone slides upon them, A
suitable formula for development is given with the box of
plates ; but one of the single-solution developers, such as Azol,
or the tabloid Rytol, can be used quite as well. It is only
when warm tones are required that the makers’ formula
becomes imperative.

With a box of such plates, a printing frame, some
developer, and some hypo solution, slide making by contact
can be put in hand forthwith. There is no need to use a deep

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