[pure-silver] Re: Amidol and oxidization

I'm sure I never added any citric and the activity dropped to practically 0 
after X amount of time.  I distinctly remember looking at pale under-developed 
prints in the tray and realizing it was time for the next batch of dev.. to be 
made



________________________________
From: Richard Knoppow <dickburk@xxxxxxxxxxxxx>
To: pure-silver@xxxxxxxxxxxxx
Sent: Saturday, May 23, 2009 4:43:03 PM
Subject: [pure-silver] Re: Amidol and oxidization


----- Original Message ----- From: Eric Nelson
To: pure-silver@xxxxxxxxxxxxx
Sent: Saturday, May 23, 2009 2:19 PM
Subject: [pure-silver] Re: Amidol and oxidization


I was probably working with the formula from Blumann


Water          500mls
Amidol        3.3 gms
Sulfite           22gms
Pot. Bromide .3gms


Blumann recommended only for small lots of prints which was true enough.  I 
tried this back before the internet (or my awareness of it) so all I had to 
work from were my historical texts and didn't really work w/it much after that 
and I have only used it for a speed boost w/PMK since then.


So the extended life comes from the citric acid in the formula you use?


Eric


    This is approximately a half volume version of the Agfa/Ansco formula, with 
a bit more Amidol.
    I've seen Amidol formulas with up to 10 grams/liter of Amidol. There are 
also some "acid" Amidol forumulas with some sodium metabisulfite in them. The 
Chamlee's formula has some acetic acid in it. As I stated in my previous post, 
it is possible that acetic acid, may have some special property beyond simply 
modifying the pH which stretches the life of the developer. Unless the 
Chamlee's have run comparative life tests I know of none in the literature.

--
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx 
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