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Fred Braakman |
21:59 5 Feb 06 |
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Steve Nicholls |
23:20 5 Feb 06 |
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Steve Nicholls |
18:16 5 Feb 06 |
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Ike |
11:42 24 Jan 06 |
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Louie Pasto |
17:31 10 Jan 06 |
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Jorge Gasteazoro |
19:09 10 Jan 06 |
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Louie Pasto |
5:01 11 Jan 06 |
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Jorge Gasteazoro |
9:10 11 Jan 06 |
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Louie Pasto |
20:26 17 Jan 06 |
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Re: Film/developer combination for PRSP |
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Phil Davis |
9:50 18 Jan 06 |
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Louie --
If I understand your question correctly I'd say the only thing missing from your proposed procedure is the final practical step of relating this calibration method to the manufacturers' published film speeds—and this is important only because your meter expects to receive these "official" speeds as a basis for its exposure calculations.
In fact, you're on track here to "discovering" the ISO calibration method. Test films are exposed to a range of fractional lux-second intensities, typically in the (log10) range of 1.0 to -3.0, for time appropriate for the film's normal use, then developed to a standard gradient so that a standard speed point can be located (0.1 over B+F). The log10 value of exposure represented by that speed point is applied to a look-up table to find the ISO speed number. For example, if the test film's speed point exposure falls within the range from -2.06 to -2.15 (inclusive) the film is assigned the "ISO 100" rating.
So, to answer your question: Yes, you can calibrate the x-axis in EFS values although I think using the information in the field would be a little awkward.
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