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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.