[pure-silver] Re: Fishy developer: NOW Triethanolamine
- From: Jordan Wosnick <jwosnick@xxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Wed, 22 Dec 2004 09:32:11 -0500
I agree with you, Ryuji, that the concentration *should* be a major
factor, and that using the developing agent to control pH is not
optimal. I think it is happening here, though. Pat Gainer reports
that above a certain concentration range, additional Vitamin C in
the soup makes little difference to the activity of the developer.
It could be that the acidfying and redox properties of extra
Vitamin C are partly cancelling each other out in this situation.
Jordan
Ryuji Suzuki wrote:
> The rate of development in superadditive developers is often limited
> by the rate of electron transfer from the developing agent (ascorbate)
> to the electron transfer agent (phenidone), unless it is limited by
> the cathode process. (Cathode process tends to become more limiting in
> the later part of development, especially in tabular grain crystals.)
> So the concentration of ascorbate is a major factor even if it is "far
> more than is needed" and I would adjust the ascorbate concentration
> and the pH separately.
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