Reciprocity Failure Compensation

Because film emulsion has issues with very long and very short exposures (reciprocity failure) it is necessary to compensate for the exposure.

Reciprocity Failure Compensation for long exposures:

Indicated Exposure
X Compensation
Acutal Exposure Time
1 Second
X 1.25
= 1.25 Seconds
5"
X 1.5
= 7.5 "
15"
X 2
= 30 "
45"
X 2.5
= 1 minute 52 Seconds
2 Minutes
X 3
= 6 Minutes
5 "
X 4
= 20 "
10 "
X 5
= 50 "
20 "
X 6
= 2 Hours
40 "
X 8
= 5.5 Hours

Emulsions may vary times.