Rodrigo Whitaker Salles (rwsalles@provida.org.br)
Fri, 22 Jan 1999 01:05:55 -0200
At 13:12 21/01/99 -0500, you wrote:
>In a message dated 1/21/99 2:12:46 AM Pacific Standard Time,
>rwsalles@provida.org.br writes:
>
>> Considering a normal development, what step in the T-14 corresponds to a
>> neutral 18 %gray card ?
>
>I am not sure if you are asking the density of a gray card, or if you are
>asking what the density of the film should be if you shoot a gray card with
>exposure metered with the gay card (for zone system calibration). I
believe it
>is the latter. Since this is not directly related to alt. process, I will
>answer briefly. Feel free to contact me offlist if you have more questions.
>
>For zone calibration, you need to find not just the development to produce
the
>right density, but also the system speed. In brief, the following is the aim:
>
>gray card minus 4 stops (underexposed) should give 0.1 + base+fog
>gray card plus 2 stops (overexposed) should give approx. 1.05 + base + fog
>
>base+fog is different from film to film, so make sure you account for that.
>For example, b+f of TMax100 roll film is about 0.24.
>
>You can then compare your target value with a step tablet. Cor has listed the
>densities of the steps, so I won't repeat.
>
>
>Dave
Thank you Dave and Cor for your answers.
The problem I face is: "how should I calibrate my system (lens, shutter
speeds, agitation method, enlarging method - mine is by condensers - with
Bergger 200 Film developed with PMK?" I've been reading many books on the
subject, but I confess I'm trying to mix alt processes with zone system. I
don't know any lectures or masters on the matter here in Brazil who could
show any hint, so all I have are books (in english) and good willing people
like you.
I know this is a basic question, perhaps it shouldn"t be here, but I think
it is related to alt processes as well, since I must get negatives of
contrast range about 1.8 to 2.0 for both cyanos and Pt/Pd.
Anyway, thanks to both of you and others who answered my questions.
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