From: Sandy King (sanking@clemson.edu)
Date: 08/05/03-08:01:20 PM Z
Manuel,
>
>To be honest , I've never tried to test the maximum capacity of my Expert
>drum.I'll try to do it tomorrow.
>
>
>>From what you wrote about the volumes of developer you use at 2:2:100
>to develop a sheet of 20x24 , I can deduce that 500ml for five 8x10's is
>not enough or at least not the ideal amount.
Right, I think that 500ml for five 8X10 sheets of film is not enough
developer, even with the 2:2:100 dilution. I imagine you would get
enough development with normal SBR scenes but the developer would
probably exhaust before you get enough contrast with N+1 and N+2
negatives.
>
>So after all this time spend discovering the attributes of BPF200(to be
>more precise I'm using Forte 200, that I assume is the same stuff) we can
>conclude that is not suitable for scenes with sky or smooth surfaces ?
I would not go that far. I am just saying that I have gotten better
results with FP4+, which has about the same effective film speed as
BPF, and responds much better to N+ development.
>
>I'm now beginning my tests with FP4+ in 8x10 because my magic hour is
>twilight and with BPF 200 or equivalent I'm not getting enough contrast for
>PT/PD. That film "closes in itself" at low contrast scenes even at 2:2:100
>at extra time, producing inconvenient B+F even when taking care of not
>overexposing the shadows.
This is absolutely correct. BPF has what we call finite gamma,
meaning that once you develop long enough to get to a certain CI
additional development merely adds density everywhere on the curve.
The practical effect of extended development is simply more density
and longer exposure times with no gain in contrast. Real bummer.
Sandy
>
>Thanks again .
>
>Manuel
>
>
>
>
>
>> From: Sandy King <sanking@clemson.edu>
>> Reply-To: alt-photo-process-l@sask.usask.ca
>> Date: Tue, 05 Aug 2003 17:52:14 -0400
>> To: alt-photo-process-l@sask.usask.ca
>> Subject: Re: Pyrocat-HD capacity question for Sandy
>>
>> Manuel,
>>
>>
>>
>>>
>>> You wrote once the following about your miraculous Pyrocat-HD :
>>>
>>> "My testing with Pyrocat-HD is based on 6ml of working solution per 20
>>> square inches of film, so an 8x10 sheet of film needs a minimum of about
>>> 500ml of working solution."
>>>
>>>
>>> My question is :
>>>
>>> If you use the Jobo expert drum for processing that means that you
>>> should use 2500ml of solution to develop five 8x10 sheets ? That seems
>>> unrealistic in terms of drum capacity and processor motor.
>>> What volume do you advise for developing 5 8x10 sheets in an
>>>Expert drum ?
>>
>> You can reduce the quantity of developer to about 250ml per 8X10 film
>> with the 1:1:100 dilution, a little less with the 2:2:100 dilution.
>> That is conservative. I actually use only about 1 liter of solution
>> of the 2:2:100 dilution to develop a sheet of 20X24" Ilford FP4+.
>>
>>> I'm getting some mottling mainly in sky areas, as that
>>>inconvenient law of
>>> nature determines, with BPF 200 at 2:2:100, 500ml volume ,speed "P". Can
>>> this problem be related with the developer volume I'm using ?
>>
>>
>> My advice is to change films. I too have encountered mottling in sky
>> areas with BPF with Rollo Pyro as well as Pyrocat-HD. There is
>> absolutely no reason I know of that the developer itself should cause
>> mottling withe the volume per film area and the the agitation method
>> you describe.
>>
>> Sandy
>>
>>
>>
>>>
>>>
>>> Thanks in advance for your always rewarding and useful support you give to
>>> us all . :-)
>>>
>>> Kindest regards
>>>
>>> Manuel
>>> Punctum Studios
>>> Portugal
>>
>>
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