is suitable for line drawings and illustrations that have been
screened for printing. The film requires a longer exposure
time than the paper.
(2) Place a yellow filter over the reflex medium to filter out the
ultraviolet light, and then press the top of the printing frame
or another sheet of plate glass down to hold the illustration,
reflex medium, and filter sandwiched together.
(3) Expose the illustration. When the illustration is exposed,
the light must pass first through the filter and then through
the reflex medium, so that it strikes the illustration and is re-
flected back to the emulsion side of the reflex medium. De-
termine correct exposure time by exposing test strips of the
reflex medium for varying lengths of time. Then develop
the strips (c below). If exposure is too short, the paper will
show a gray background. If exposure is too long, the paper
will be clear. but the image will have faded. The projection
stage of Projector PH-637(*)/PFP may be used as a source
of light for exposure.
c. Development.
(1) Submerge the exposed paper or film in a tray of developing
solution. Dektol or D-72 type developers are recommended.
The rate of development will be rapid and may be retarded
by diluting the stock developing solution with 2 parts of
water.
(2) As soon as the image is sharp, transfer the paper or film
quickly to a second tray containing a short stop, which can
be prepared by adding one part of 28-percent acetic acid to
20 parts of water.
(3) After the paper or film has remained in the short stop for
a few seconds, transfer it to a fixing solution. Mix the
solution in accordance with the instructions on the container.
Leave the print in the fixing bath for several minutes.
(4) Remove the print from the fixing bath, and rinse it thor-
oughly with water. Then hang it up to dry.
(5) The resultant print is translucent and may be used to re-
produce the image on Ozalid foil (par. 28).
30. Multicolored Transparencies and Overlays
multicolored transparencies freehand in ink.
b. Tracings in the Prepration of of Overlays (fig. 18).
(1) Make one complete tracing of the original (par. 27e).
(2) Prepare a seperate tracing of each part that is to appear in
a different color. Be sure to include register marks on each
tracing to insure correct alinement.
31
TAGO 4738B
