DARKROOM AUTOMATION F-STOP, Instruction Manual

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Contrast Control or Independent Exposures
The two base exposures for split grade printing are labeled
H
for high contrast and
L
for low contrast. The two can be in any order.
There are two options in how the
H
and
L
exposures relate to each other. The
selection is made in the timer’s setup mode and applies to all split grade printing.
The selection can be changed at any time but the exposures stored in memory will
have to be manually reprogrammed from the one scheme to the other:
• The two exposures can be linked so that the first controls the overall print
exposure and the second controls the print contrast. Only the first base
exposure needs to be changed when changing base exposure to compensate
for changes in print size or other factors. The second base exposure is set in
stops plus/minus the first base exposure and so the ratio of green to blue light,
and hence the contrast, remains constant.
• The two exposures can be independent and both exposures affect print
exposure and print contrast. When the print exposure is adjusted both the
high and low contrast base exposures will need to be changed. This
independent mode has traditionally been used for split-grade printing where
two test-strip prints are made to determine the
H
and
L
exposures: a high
contrast filter test print for blacks/deep shadows and a low contrast test print
made for the whites/highlights.
Tracking
Dodges and burns all track their respective base exposure, as they do for single-
grade printing. Dodges and burns placed after the high contrast exposure track the
high contrast base exposure and those placed after the low contrast exposure track
the low contrast base exposure.
Because of this the contrast of the dodges and burns will track changes to the over-
all contrast of the print.
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