[pure-silver] Re: Food Grade Chemicals
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Thu, 11 Jul 2013 10:21:13 -0700
----- Original Message -----
From: "Myron Gochnauer" <goch@xxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Thursday, July 11, 2013 6:20 AM
Subject: [pure-silver] Re: Food Grade Chemicals
I have used 20 Mule Team Borax and household ammonia from
the supermarket. Both worked as expected.
I would be very surprised if the difference between food
grade and reagent or laboratory grade made any difference to
ordinary photographic processes.
... they only supply "food grade" chemicals.
My understanding is that photo grade chemicals have low
levels of photographically active impurities but other
impurities can be there. Reagent grade comes with an assay
showing exactly what is in it, that's why its expensive. It
may be no purer than other forms.
Sodium carbonate: There are three common forms,
anhydrous AKA desiccated, monohydrated, and crystalline.
Kodak usually specified the anhydrous form, AGFA the
monohydrated form and crystalline is found mostly in old
British publications. Monohydrated is the most stable
because anhydrous will absorb moisture from the air if not
kept in a sealed container.
Kodak and AGFA specified granulated borax, presumably
granulated crystals but not specifically stated. The
definition in the old Photo-Lab-Index seems to show it to be
the decahydrate.
--
Richard Knoppow
Los Angeles
WB6KBL
dickburk@xxxxxxxxxxxxx
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