From: clay (wcharmon@wt.net)
Date: 10/31/01-09:36:40 PM Z
Sandy:
I decided to try your pyrocat HD developer for a batch of negatives that I
will use for platinum printing. I normally use D-76 and a densitometer to
figure shadow density versus highlight density and then plan the contrast
mixture accordingly. Is there any rule of thumb for converting transmission
density of the stained negatives to an equivalent for unstained negatives?
Is the actinic filter effect less than that of a yellow-green rollo-pyro
stained negative? I hope it is, because my only beef with pyro has been the
incredibly long printing times. BTW, I can already tell that the pyrocat
handles highlights as well as pyro. One of the images has a lit lamp, and
there is NO halation, while the D-76 negatives have a great deal when
imaging a similar subject.
Thanks,
Clay Harmon
----------
>From: Sandy King <sanking@clemson.edu>
>To: alt-photo-process-l@skyway.usask.ca
>Subject: Re: step wedges; POP and gold toner
>Date: Wed, Oct 31, 2001, 5:30 PM
>
>Shannon,
>
>Much of the previous discussion has focused on making prints. Your
>problem appears to be in the density of your negatives.
>
>That being indeed the case, and correct me if I misunderstood you,
>you will need to adjust the exposure of your negatives by rating the
>film at a higher EI. I can't tell you exactly how much because that
>will depend on several factors, including how you meter, developer in
>use and film. However, try doubling or even quadrupling the EI that
>you use to meter.
>
>If the question is merely that the shadows in your prints are too
>dense by about two stops, that represents an overexposure in printing
>of about two stops, equivalent to a density difference of 0.60.
>Reduce your exposures by a factor of .25 or .50. For example, if the
>offending exposure is 100 seconds, reduce to 50 seconds to for a
>density change of minute 0.30, or to 25 seconds for a change of 0.60.
>
>With all POP processes the key to good contrast is to keep the
>density of your negatives low in the shadows. Anytime negative shadow
>density goes over about 0.40 it becomes very difficult to get good
>contrast from POP processes because of their self-masking feature.
>Lacking a densitometer, a rough guide to 0.35 on the exposing
>negative would Step Four on the transmission step wedge (Stouffer,
>Kodak, etc.).
>
>Sandy King
>
>
>
>
>> A few days ago, I think I read on this list that two steps on the
>>step wedge equals one stop. Is that correct? I am trying to figure
>>out how to change my EI, because the shadows in my negatives shot at
>>320 are about two steps too dense. Does that mean I'm over exposing
>>one stop, approximately?
>>
>>Also: I am printing on Centennial POP. The brochure that came with
>>it says to replenish the gold chloride toner after one 8x10 print. I
>>cut my 8x10 sheets into four rectangles, so I thought that I could
>>tone and fix four of these small prints, one after the other, before
>>I had to replenish. But, that doesn't seem to be the case. After two
>>prints, the toner is exhausted and doesn't replenish easily by
>>adding 6mls of solution A and B, as advertised. I am wondering if I
>>should hold all four prints in water and then tone them all at once
>>in the gold toner? CAn you do that?
>>
>>--shannon
>
>
>--
>
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