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To alleviate anomalies such as sun angle effect and the
lack of light intensity in perspective projector lenses,
two separate procedures were employed. First, a color
CRT was used on the MRK-IV printer to amend the contrast
shift due to the Sun's reflective rays. Secondly, a 0.30-
density value vignetting filter was fabricated and placed
in the lid of the printer below the photomultiplier tube
to correct the peripheral density decrease.
PROCEDURE
A sample image was selected from the CIR positive film
and a RED (Kodak #25) color separation filter was
placed in the MRK-IV printer with the original CIR
film in position for reproduction. A Kodak 21-step
0.05-incremental step tablet was placed on the stage
plate adjacent to the film along with a Kodak tricolor
guide. This not only served as a guide when recon
struction of the separation was accomplished, but also
determined the stability of the color filters being
used by demonstrating "leaks" or "bleed through" of
other colors if they occurred. The negative separa
tion film Dupont CCMS-7, (10 by 12 inches) was sufficient
to cover the original aerial film (9 1/2 by 9 1/2 inches)
and the guides. Empirically, exposure parameters were
determined along with automatic processing gamma to
return a 0.30 minimum density value (Dn) on the red
color separate, and the inclusion of a step wedge and
color guide enabled monitoring of their reproduction to
insure that exposure and processing remained consistent.
A 1.0 density range (aD) was established to be compatible
with "in-house" equipment, and the RED separates were
set up as "controllers" to be followed by the GREEN
and BLUE separates. The results of the processed RED,
GREEN, and BLUE color separates (now B/W negatives)
demonstrated the electronic masking capabilities of
the MRK-IV printer, which eliminated the need for silver
masks and provided the means to reproduce a large
color orthophotoquad project while at the same time
adhering to a project density control system* (PDCS)
for reproduction.
SYSTEMS APPL[CATION
A red filter was positioned and calibrated to the
MRK-IV contact printer. Exposing and processing
parameters were established for the project based
on the density control system. Beginning with roll
1 of the CIR positive film, all alternate frames
were exposed and batch processed. A maximum density
(Dx) of step 14 on the step tablet was used to control
* See Brumm and Waters, 1977, for further information
on processing large blocks of orthophotoquads by project
so that tone matching is achieved from quad to quad.