202
Home-Made Motion -Picture Camera and Projector
IN THREE PARTS— PART II
Developing ing either negative or positive film,
After havin.tr exposed the film in the small test strips should be run through
the solution so that the proper timing
camera, the next steps are to develop
and treating of the full-length strip will
and make a positive film from the nega-
correspond to the test strip.
tive. The developing and exposing of
A reel should be prepared for drying
the film. This can be made of small
slats placed around two disks to form
a drum (Fig. (;) about iVi; ft. in diame-
ter and gi/o ft. long. After the film has
been passed through the various solu-
tions and is ready for drying, it is
wound spirally around on the slats with
the gelatine side out, and the whole
Fig. 4 — Cross Arms with Pins
hung up to dry.
the film for the positive are the same Printing
as in ordinary photography for making The printing to make the transpar-
negatives and lantern slides, the only ency is accomplished by a very simple
difference being in the apparatus for arrangement. The negative and posi-
handling the long films. One of the tive films must be drawn through a
simplest ways of developing a long space admitting light while their gela-
film is to use a large tray in connection tine surfaces are in close contact. A
with a cross arm having upright pins box may be constructed in several
around which the film is wrapped in ways, but the one shown in Fig. 7 il-
a continuous spiral. A film 100 ft. long lustrates the necessary parts and their
would require a tray 18 by 22 in., with relative positions.
pins set in the cross arm about in. % The sprocket A is placed directly
apart. This method of developing is
back of the opening B v/hich may be
shown in Fig. 4. regulated to admit the proper light.
A long film can be developed in a The sprocket can be purchased from a
small tray by using two flanged wheels
or spools mounted on a frame (Fig. 5)
that holds them directly above the
liquid in the tray. The spools have a
wood core or center with metal sides of
sufficient diameter to take in the length
of film to be developed. One end of
the undeveloped film is attached to one
spool and then wound upon it, then the
other end is passed through the guides,
gelatine side down, and fastened to the
other spool. The film is first run
slowly through a water bath until it is
thoroughly saturated, then it is passed
through the developing solution again
and again until the proper density is se-
cured. The trays can be easily re- Developing Long Films
moved and others substituted for fixing",
hardening and soaking, the moving-picture stock house cheaply,
washing,
film being passed through each solution
but if the builder so desires, one can be
in the same manner. Before develop- made from wood turned up about 1 in.
203
in diameter, or so that the circumfer-
ence will receive sprockets at points t'V
in. apart. The sprockets are made of
metal pins driven into the wood. Two
rows of them are placed around the
wood cylinder about iVs in- apart.
The cylinder is provided with a small
metal shaft at each end which turns
in round holes or bearings in the sides
of the box. One of the shafts should
project through the side of the box and
have a grooved wheel, C, attached.
The sprocket cylinder is driven by a
smaller grooved wheel or pulley, D, to
which a crank is attached for turning.
The relative sizes of these wheels are Fig. 7 — Printing Machine
determined by the speed of the expos-
ure and the kind of light used. A 3-in. 10 or 15 seconds and counting the num-
or 4-in. wheel on the cylinder sprocket ber of revolutions. The proper expos-
shaft, driven by a pulley about 1 in. in ure can be easily attained by this
method.
( To be continued)
An Emergency Clamp
While makint an extra large guitar
I did not
have clamps
large enough
to hold the
top and bot-
tom onto the
sides while
Fig. 6— Drying Reel gluing, so I
diameter, will be suitable under ordi- fastened
nary circumstances. three pieces
The opening B
may be adjusted by two metal slides of wood to-
which fit tightly in metal grooves fast- gether, each
ened to the wood front. The metal piece being
grooves and slides can be made of tin about 1 by 3
and painted a dead black. The films in.,as shown
after passing over the sprocket, fall in the sketch.
into the bottom of the box, or, if very Then I bored
long films are to be made, the instru- holes in
ment can be used in the dark room and both top and
the light admitted only to the opening bottom
B, then the ends can be dropped into a pieces and inserted a piece of soft wire
basket or other receptacle at the bot- in the form of a loop, which, when
tom and the unprinted portions carried twisted, drew the ends of the clamp
on reels above the box. together. —
Contributed by Geo. E.
The speed of the exposure and the Walsh, Buffalo, N. Y.
width of the opening B can be deter-
mined by making test strips. This can CWhile camping, remember a hot
be done by setting the opening B to a stone wrapped up makes an excellent
certain width and turning the crank for substitute for a hot-water basr.
204
Home-Made Motion-PicUire Camera and Projector
IN THREE PARTS — PART III
The Projector The lamp house is made of ordinary
The film positives are projected on stovepipe metal and the dimensions
a screen with the same kind of a lan- given in the sketch are for a size suit-
tern as is used for lantern slides, with able to use an acetylene or gas burner.
the addition of the device for stepping The metal is laid out as shown by the
the film through, one picture at a time. pattern (Fig. 9) and bent on the dot-
ted lines to form the sides
and ends of the house.
The joint may be riv-
eted, or, if taken to
a tinshop, lock-seamed.
The cover is cut out as
shown, the sides and ends
having bent holes which
are covered on the inside
with perforated sheet
metal. A. In order to de-
small an-
flect the light, a
Fig. 8 — Projector Complete
gular strip, B, is riveted
and flashing light on each picture as on so that its upper portion will cover
it remains stationary for an instant. the holes and allow a space for the heat
The projector (Fig. 8) is composed of to pass out. The cover may be hinged
a lamp house, a condensing lens to or set on like a cover on a can. The lamp
make the beam of light converge up- house is attached to a sliding wood base
on the film for illuminating it evenly, for adjusting its position on the base-
a film-stepping device, and a project- board.
ing lens for throwing the enlarged pic- The condensing lenses are fixed into
ture of the illuminated film upon a a metal barrel having a tapering end.
screen. This can be made of the same material
Fig. 9 Details of the Lamp House
205
as used in the lamp house. The parts of the required size, or a lens of 12-in.
can be rolled and a lock joint made at focus enlarEjinsj a 1-in. film to about 6
a local tinshop, or the pieces shaped ft. at a distance of 24 ft. A
regular
over a wood form and riveted. Small lens fitted in a metal tube can be pur-
L-shaped pieces are riveted to the in- chased from a moving-picture stock
Fig. 10 — Details of the Lamp, Stepping Device and Base
ner surfaces to hold each lens in place. house at a reasonable price. The box
A rim is turned up on the back end of is made upsimilar to the camera box,
the metal tube for attaching the lens but with a metal back instead of the
barrel to the lamp house. wood. The intense heat from the light
An ordinary mantle or acetylene would quickly burn the wood and for
burner is attached to a gas pipe that this reason the light should be kept
has for its base a drop elbow fastened from the film while it is not in motion.
to a sliding board similar to the slide of The projecting lens barrel should be
the lamp house on the baseboard. A fitted snugly, yet loose enough for
good reflector should be attached to a focusing.
standard just back of the burner. The The baseboard is cut as shown and
standard is also fastened to the slid- the film-stepping device is firmly at-
ing board. The proper distance of the tached to the small end. The sides ex-
light from the condensing lens can be tend over the baseboard and are fas-
easily set by this adjusting device. tened with screws and braced with
This arrangement is shown in Fig. 10 metal brackets. The slot in the small
in the diagram entitled "lamp parts." end of the baseboard is for the film to
The device for stepping the film is pass through. The film should have a
a duplicate of the one used in the cam- tension the same as in the camera with
era as described in Part I, with the ex- velvet placed on the edges of the par-
ception of the lens. The lens should titions. It is well to have a guide be-
be about 2 in. in diameter with such low the roller shutter to keep the film
a focal length that will give a picture from encircling the roller as it turns.
