Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1890-12-21
ON THE MAGIC SHEET.
How Amateur Photographers May
Entertain Their Friends
BY AID OF THE STEREOPTICON
Production Of the Slides From the Mega
tives Of the Camera.
THE LAST OF THE DISPATCH PAPERS
WRITTEN FOR THE DIsPArcH.l
Seventh and Last Paper.

|
tions in which the amateur photographer
can turn his skill is the making of lantern
slides and exhibiting the results of his en-
deavors by means of stereoptlcon.
Pictures of all kinds, when thrown upon the
screen in an enlarged form, are all the more
interesting because OF their being all your
own, and your friends will appreciate them
more fully as the exhibition takes on the
aspect OF an illustrated lecture on subj ects
in which all are more or less directly in
terested. The stereopticon can be procured
from any dealer in optical or Photographic
supplies at prices ranging from $40 upward.
An hour or so whiled away with such enter
tainment is as instructive as it is thoroughly
amusing.
The process of preparing slides from ordi-
nary negatives is by no means a difficult
one. and is within the capabilities of almost
any operator who has made fair progress in
the art Two young ladies, to the writer
knowledge, who have had less than years 8
experience, have prepared collection of
lantern slides from negatives made during
the past su MINER, which will compare favor
ably with the work OF professionals. At a
recent private exhibition they displayed
over 100 different views, embracing bits of
marine scenery, landscapes, groups. mount
ain glimpses, etc. All were good, and their
chief charm lay in the fact that they were
homemade.
| MAKING THE SLIDES.
The work Of reducing negatives to the size
| required for the lantern slide is largely
mechanical. Of course, there is a certain
| portion of it which must be controlled by
| judgment, but that is small indeed. A posi-
tive is made on glass from the negative, the
plates to be used being specially prepared
for the purpose. They yield clear, sharp
black-and-white effect, throwing distinct
shadows on the object sheet. These positive
| plates can be made by direct contact in q
| printing frame, but, as rule, they are not
satisfactory when made that way. The Ian
| tern slides are considerably smaller than
any OF the ordinary plates now in use and in
making contact slide, Only section of
the negative is secured and the effect is sell
dom good. Besides, it stands to reason that
a large negative reduced to the size required
for the slide, will be much more compact
and will give finer results.
| Contact printing is done on the same
principle as ordinary paper printing. Lay
the transparency plate over the negative in
your printing frame in the dark room, of
course), and expose to white light either
daylight or gaslight. for few seconds.
| Then return to the dark room and develop
the slide. A special developer is needed for
this work, requiring no more skill, how
ever, than that used in developing ordinary
dry plates. The better plan is to reduce the
negatives by the simple process which fol-
lows:
REDUCING THE PICTURE.
The reduction is effected with the use of a
box, or cone, which is attached to the front
of the camera. This cone should be con-
structed on the regular mathematical plan
according to these proportions: Add to-
| gether the width of the negative and the
width of the desired slide and multiply
their sum by the focal length of your lens.
Divide this product by the width of the
slide to get the distance in inches the mega
tive must be from the lens. or in other words
the length of the cone. Then divide the
product by the width of the negative to get
the distance at which the slide must be
from the lens. The slide Is exposed in a
pisteholder, which is placed in the back f
the camera at the distance from the lens de-
termined by the last calculation mentioned,
| A box constructed for negatives of the 6L
xS115 size and slides Ok inches wide (the
standard), useds in connection with SIX
inch wide angle lens, should be % inches
long. 1t is well, however, to make box 81
or % inches long, SO that it can also be used
for smaller negatives and SO that room will
he lett for the operator to uneap his lens.
The light that enters between the back, or
small end of the box, and the front OF the
camera does little if any harm. 1t can
easily be guarded against by throwing a
dark cloth over the aperture.
THE MECHANICAL DETAILS.
In the front board of the box square hole
should be cut just trife smaller than the
negative, SO the negative may rest against
! it without falling through. Little strips
nailed on the outside will hold the plate in
position. The entire box should be raised
on strong board at the proper height to
connect perfectly with the lens of the cam
era when placed in front of it. A couple of
strips of wood should be nailed on the board
to keep the camera rigidly in its proper po-
sitlon. 1t will be seen at glance that the
size of the image may be varied at will, SIM
ply by moving the camera backward or for
ward, focusing, of course, with every change
of position. Kits can be had of any dealer
to hold the little slides In large plate hold
ers.
After the camera has once been placed in
its correct position, the object carefully
focused of the required size, much future
trouble can be saved by marking out guide
lines on the board. at which the camera
must rest and also the point of exact focus
on the bed of the camera. Then the outfit
will always be ready and need not be re-
focused. II smaller negatives than those for
which the box was constructed are to be
used, kits can be used in the front board
and the camera moved a little closer to the
cone or box.
GETTING LIGHT ON IT.
Then everything is ready for the exposure,
the entire ''plant" may be lifted up care
fully by the dashboard and thrust through an
open window, taking care to rest the room end
on table or chair. 1t must be pointed up
ward to secure the clear and unobstructed
light of the skv. With most negatives it is
we'll to use small stop in the lens and give
a long exposure, say from 10 to 80 seconds,
so as to get good results in shading. With
careful treatment cloud effects in scenic
views may often be preserved.
1t is also possible to obtain excellent
lantern slides from inferior negatives. In
this way the value of these "transparencies'
is all the more appreciated. 1t is an old
maxim among photographers never to con-
denim a negative as not good until it has
been tried for a lantern slide
The method of exhibiting these slides in
stereopticons is so we'll known and simple
as to need no further explanation here.
w. o. EsCHwEGE.
A Sure Way to Interest Her.
brakes Magazine.I