The Eastman paper films for the roll-holder are prepared in
continuous bands, and are rolled up on wooden spools and neatly
packed in paper boxes.
The spool may be removed from its box and placed in the holder in
daylight, at the expense of the outside roll or length of paper
necessary to extend from the spool to the winding-reel, so that if
one were so situated as to find it necessary to change rolls in the
field, the loss would be trifling--being at the utmost not more than
would be required for two exposures from each spool.
The proper course, however, is to charge the holder with its spool
of film in the dark room before going abroad.
In doing this it is necessary that the light in the room should be
strong enough to enable the operator to see comfortably; but of such
a quality as not to injure the paper, which is at least 25 per cent.
more sensitive than the same emulsion would be if on glass instead
of paper.
Figure 1 gives a general idea of the shape of the holder, with the
slide partly drawn to show a portion of the film. Also may be seen
the brass loops or clamps [p182] which hold the cover securely
over the working parts, and the key at the bottom which turns the
reel to which the loose end of the paper is attached.
[Illustration: FIG. 1.]
[Illustration: FIG. 2.]
The working parts are fastened to a light metal frame, and consist
of a spool of film at the right end, and the winding reel at the
left, as seen in Figure 2. Both the spool and the reel are provided
with spring brakes, that prevent the uncoiling or unrolling of the
paper from either the spool or reel. The milled [p183] heads of
the chucks which hold the near ends of the spool and reel are
provided with pawls, which, while permitting them to turn easily in
the right direction, prevent the possibility of turning the other
way.
When the cover, as seen in Fig. 2, is to be removed, the keyhole
guard and the indicator knob are pulled out as far as they will
come, the two loops on each side are turned down, the cover lifted
off, leaving the working parts exposed, attached to the back of the
holder by spring bolts, two at each end of the frame. Now, with the
thumb and fore-finger of the right hand, press these bolts, and thus
release the right end of the framework, which you may turn up, as
seen in Fig. 3, which is the position for removing and replacing the
roll of film.
[Illustration: FIG. 3.] [p184]
[Illustration: FIG. 4.]
The proper method of doing this is more particularly shown in Fig.
4. With the left hand you hold the roll of film and draw back the
spring brake; now press the end of the roller that has the saw-cut
or groove across it against the chuck, as seen on the left, while
the right hand unscrews the pivot or support for the other end of
the roller, which is then placed in position; the pivot is inserted
and screwed home.
This completes the operation of placing the roll of film in
position. The frame is then turned down and secured by the two
bolts, the paper band on the roll of film is torn off, and the end
of the film is carried beneath the guide roller and over it and
across the exposing table to the other end, which is next released
and raised to a perpendicular position. The end of the film is now
brought over the guide roller and attached to the winding reel, as
shown in Fig. 5. [p185]
[Illustration: FIG. 5.]
The paper is fastened to the winding reel by a metallic clamp, which
is pivoted to the ends of the winding reel. Now see that the film
occupies a central position across the table and over the guide
rolls, and then take up the slack by means of the milled head
tension screw or chuck at one end of the reel. The pawls should now
be adjusted on the milled heads of the chucks, the cover replaced
and fastened by raising the loops or clamps over the pins in the
side of the cover, and you are ready for work.
For the purpose of indicating plainly where the first exposure will
be, insert the key and screw it home then turn it slowly until you
hear a sharp click, then pull out the slide and draw a pencil across
the film at each end of the holder, then return the slide.
When about to make another exposure, note the position of the
indicator at the right end of the holder, then turn the key slowly;
the proper length will be [p186] indicated both by the sound of
the sharp click within and by the position of the indicator on the
outside of the holder. At every turn of the guide-roll the paper is
punctured by a sharp point which occurs simultaneously with the
sound of the click. For the smaller sizes, three clicks and three
punctures will surely indicate that the proper length of paper has
been replaced on the exposing table. For the medium sizes four
clicks and punctures are required. And for the larger sizes, as many
as six or eight may be necessary. The proper information is given
with the holder.
[Illustration: FIG. 6.]
When the exposures are made, and it is desired to remove the paper
from the winding reel and cut it for development, proceed as before,
and remove the cover from the holder; then, with a sharp
knife-blade, cut the paper, as shown in Fig. 6, by drawing the blade
over the paper and in the tin-lined groove in the guide-roll Then
release the spring pawl at the reel end and [p187] draw the paper
from the reel across the table, then cut by measurement, or by
counting the punctures.
The directions for developing and preparing the films for printing
accompany each package of the paper.