Gestetner A193 Service Manual page 445

MAIN SCAN MAGNIFICATION/REDUCTION
6. MAIN SCAN MAGNIFICATION/REDUCTION
The specification of the reproduction ratios in the memory mode (binary
picture processing mode) has been changed to 5 enlargement and 6
reduction. This is because the higher copy speed of this model causes poor
copy quality at a reproduction ration of 25%.
Reproduction ratios of 48% ~ 400% are achieved for main and sub scan
magnifications in the same way as for the A193 copier, and for reproduction
ratios of 25% ~ 47%, it is done by changing the scanner speed and deleting
every other line.
SM 13-11 A224