112 
a halftone negative was made and became a magenta 
printer, and from the BLUE separate a yellow printer 
was prepared. The printing of these plates rendered a 
copy of the original CIR, rectified and geometrically 
correct. 
Efforts to obtain a natural green version of the imagery 
required some changes in the halftone screening proce 
dures. A chromatic transposition was initiated where 
the printing plates were used out of their normal 
sequence. Briefly the steps included: 
A. 1. The RED separate was used to prepare the 
black accent halftone at a 45-degree screen 
angle. 
2. The RED separate was also used to prepare 
the magenta halftone at a 75-degree screen 
angle. 
B. The GREEN separate was used to prepare the 
cyan halftone at a 105-degree screen angle. 
C. The BLUE separate was used to prepare the 
yellow halftone at a 90-degree screen angle. 
D. A unique procedure was performed at this 
point to insure proper color reproduction. 
The magenta halftone and the yellow half 
tone are both copied, dot for dot into half 
tone positive form. These two positives 
were sandwiched together and contact printed 
to obtain a new, combined yellow halftone. 
The 75-degree-angled dots add yellow to 
the magenta imagery to obtain the brown 
tones. The remaining 90-degree-angled 
dots perform their normal function of adding 
support to the cyan color to give a green 
rendition where necessary (see Figure 5)- 
CHROMATIC TRANSPOSITION 
COLOR REPRODUCTION 
Figure 5*—Flow diagram of chromatic transposition 
reproduction