[pure-silver] Re: Weird Film Issue

  • From: Jean-David Beyer <jeandavid8@xxxxxxxxxxx>
  • To: pure-silver@xxxxxxxxxxxxx
  • Date: Mon, 07 May 2012 11:58:31 -0400

Tim Daneliuk wrote:
> On 05/07/2012 09:56 AM, Luis Miguel Castañeda wrote:
>> Acetic acid as is used as stop bath helps to clean those hard water deposits.
> I avoid acetic acid for film stop because of the possibility -
> however remote - of pinholing the negs.  This was a way bigger
> deal in the past than it is today, but my entire workflow
> has been calibrated a particular way and I'm loathe to change it
> at this point.  I open tank process everything and use running
> water as a stop bath.
I never had pin holing, and my water is not very hard (6 grains). I do
mix my PhotoFlo with a small graduate at about 5/6 the concentration
recommended by Kodak and use distilled water for it. When using a
"capful" fo the 200 stuff, it always came out much too strong. I do not
use distilled water for anything else. I do have a 5 micron filter on
the output of my water mixing valve to remove the solids, but it does
nothing for dissolved stuff.

It would seem to me that pin holing would be the result of the acid
reacting with the carbonate in the developer to make tiny bubbles
(microbubbles?) in the emulsion that burst when the emulsion is soft.

But most film developers now days contain borax or metaborate and not
carbonate. A few contain only sodium sulfite.

So if you are going to get pin holing _after processing_, from where
would the carbonate come? Would there be any left after the film was in
the stop bath and the (usually) acid fixing bath?

It seems to me that unless you are using an alkaline processing
technique, you should be safe to put a little acid in a post hypo-clear
rinse if you think it is necessary to clear hardness from the film.

  .~.  Jean-David Beyer          Registered Linux User 85642.
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