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The DEPROS systematically scanned the model, generating 
after processing an enlarged 1 :25,000-scale dif 
ferentially rectified film positive. The GREEN and 
BLUE separates of this model were also scanned using 
the same data. 
The color-separate (RED, GREEN, and Blue) positives 
were then converted to halftone, screened negatives. 
Using the RED separates as the controlling image, 
a project Dn was determined from a flight line in which 
all frames are within a single roll. Por example: 
Roll 1, exposure 18, contains the density values of: 
Dx 1.20 Dn 0.30 
A project Dn of 0.30 was programmed to return a 90 per 
cent halftone dot in conjunction with a proper proces 
sing gamma established through tests, where the Dx 
density 1.20+ returned a 10 percent dot. 
Normal color reproductions from black-and-white color 
separates would produce a copy of the original, in 
this case an enlarged, 1 :25,000-scale geometrically cor 
rect infrared image (see Figure 4). This involves 
making halftone negatives from the GZ-1 continuous-tone 
positives. Regular color reproduction requires the 
preparation of two negative halftone printers* from 
the RED separate, one to become a cyan printer, the 
other a black accent printer. Prom the GREEN separate 
ORIGINAL 
GEOMETRICALLY CORRECT 
Figure 4*—Plow diagram of normal color reproduction 
* Halftone printers: final halftone negative, 
densimetrically correct for four-color reproduction. 
This printer is used to prepare the actual printing 
plate.