4
September 2009 D-32
Physical properties
Nominal thickness data (mils
)
* Static-resistance — process-survivable
† Unprocessed
Exposure
The following table indicates values for 1/25-second tungsten exposures
calculated using the formula 45/H, where H is the exposure in lux-seconds
required for a density of .10 (1.20 for 2462 Microfilm) above minimum density
with indicated processing. This number can be used directly with incident-light
meters.
Meter Setting Value
— recommended processes
Reciprocity data
For the Direct Duplicating Microfilms (2468/3468 and 2470), tungsten
exposures from 100 to 0.001 seconds, and processing in a
Kodak Prostar
Processor as recommended, reciprocity failure is negligible and no correction
is normally needed. Similar results are expected with other recommended
processes.
With Duplicating Microfilm 2462 and using other than 1/50-second tungsten
exposures, correct for reciprocity failure at a density of 1.20 above D-min as
follows:
*for
Kodak Prostar
Processor and continuous strand.
Microfilm
Base* (mils Estar)
Total†
2462, 2468, 2470
4.0
4.2
3468
2.5
2.7
2462
2.1
2468/3468
0.2
2470
0.12
2462
Exposure Time (seconds)
100
10
1
1/10 to 1/100
Speed change (%)
-75
-50
-20
none
Effective meter setting*
0.5
1.0
1.6
2.1
Correction in camera stops
+2
+1
+1/3
none
