[pure-silver] Re: Pyro in a Jobo Processor
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Thu, 17 Mar 2005 16:26:32 -0800
----- Original Message -----
From: "John Black" <jblack@xxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Thursday, March 17, 2005 12:14 PM
Subject: [pure-silver] Re: Pyro in a Jobo Processor
>
>>
>> Rollo Pyro uses EDTA-Na4, I believe, to sequester rotary
>> oxidation.
>>
>
> Hmmm... I've got to look this property up. I really don't
> think EDTA can
> sequester non-metallic series elements, there must be a
> different mechanism
> involved.
>
> Now where did I put my Haist...
>
> JB
>
My understanding is that EDTA holds metallic salts like
Magnesium carbonate in suspension. Parhaps it has some
effect on oxidation products of developers also. Sodium
sulfite preferentially absorbs oxygen to prevent is
oxidising the developing agents. Sulfite has several
functions in developer but this is a principal one.
Rotary processors use rather small amounts of developer
in thin layers, a condition guranteed to cause aerial
oxidation. Pyro developers appear to be particularly
vulnerable to aerial oxidation although they are also
supposed to be fairly good about not causing aerial fog. It
seems to me that Pyro developers are just not a good choice
for drum type processors.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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