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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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Re: Film/developer combination for PRSP |
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Louie Pasto |
20:26 17 Jan 06 |
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OK, I’ve now done a bit more reading and I think the purpose of the PSP is more clear to me. Thanks for refering me to Phil's article. I am not currently using the plotter, just doing everything by hand as outlined in the book.
I have also been asking myself some questions, however. If we could calibrate the x-axis of our characteristic film curve with absolute values, rather than relative ones, could we not then read each curve’s EFS directly? I tried this simple procedure as an approximation. Using my Sekonic meter in incident mode, I calculated the illuminance on my baseboard to be about 3 Lux. A one second exposure at this illuminance would equal 3 lux-seconds of exposure (I think). Now if I expose a sheet of film in contact with a calibrated transmission tablet I could calculate the approximate exposure in Lux-seconds that the film receives under each of the steps of the tablet. For example, a LogD of 1 on the step tablet transmits 10% of the light that hits it. So a 3 Lux-second exposure through the 1 LogD step would be equivalent to 3/10 Lux-seconds of exposure striking the film. In this fashion the x-axis could be labelled with absolute exposure values. In this way, could the EFS of the curve not be obtained directly?? What important steps am I missing here???
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Phil Davis |
9:50 18 Jan 06 |
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