Materials are
available for viewing microfilm copies (similar to a
(3) Special materials.
available for use with the ozalid process which
slide viewer) and for making prints directly from
produce a large variety of results, including many
microfilm copies. Since the image must go through
colored lines on white paper or colored lines on a
the original optical reduction, development of the
clear plastic background.
microfilm, enlargement, and the final print process,
the chance of distortion is high.
c. Optical Processes.
1-9.
HANDLING PRINTS
(1) Electrostatic. An electrostatic copier
(Xerox machine for example) projects an image of
a. A complete drawing represents too much
the original on paper and then causes an electrostatic
time and effort to be treated casually. It is a valuable
charge to be deposited where the image of a line
record, and must be preserved with care. If an
occurs. A black powdered "ink" is then applied to
original drawing were to be used on the job and
the paper and adheres where the electrostatic charge
passed from man to man, it would soon become worn
occurs. The image is then fused to the paper. This
and too dirty to read. For this reason, working
process produces a dark gray image on a white
drawings used on the job are almost always
background. The amount of distortion depends on
reproductions of original drawings.
the type and quality of the optical system which
projects the image on the copy paper.
b. A little time spent in carefully folding and
filing prints at the start will prevent a lot of
(2) Photostat. The photostat process is a
inconvenience later on. The method of folding
photographic process which uses a special camera
depends on the facilities available for storage. Some
and film. The film is opaque paper instead of
filing equipment commonly used is shown in figure
transparent film as in ordinary photography. Since
1-30. When manufactured filing equipment is not
the negative is opaque and cannot be viewed from the
available in the field, storage facilities should be
back, the camera is designed to produce an erect
constructed. Prints should be folded so the drawing
image instead of reversed image as with ordinary
number is visible when the print is filed. If storage
cameras. The photostat process produces white lines
space is available to accommodate rolls, prints over
on a black background (negative photostat) which
40 inches long are usually rolled instead of folded.
can then be rephotographed to produce a black image
Original drawings or intermediates used for contact
on a white background (positive photostat). The
process reproduction should never be folded; the
image can be enlarged or reduced in the photostat
creases will prevent close contact with the copy
process, usually to 1/2 or 2 times original size in each
paper.
stage.
c. When using prints on the job, avoid long
(3) Microfilm. For economy of storage
exposure to direct sunlight or the prints will fade. If
space and for insurance against destruction of the
it is necessary to mark a print, be neat and use a
original, many drawings are photographically copied
colored pencil. A red pencil is normally used to
on microfilm. When a drawing is no longer in
show additions and a yellow pencil is used to indicate
frequent use, the original is often disposed of and
deletions. After using a print, refold it carefully to
only the microfilm copy is retained. Equipment is
avoid adding unnecessary creases.
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