[pure-silver] Re: HCA (was dichroic fog)
- From: "Koch, Gerald" <gkoch02@xxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Wed, 5 Apr 2006 09:09:11 -0400
Five grams each of EDTA and citric acid represent the maximum percentage
as listed in the MSDS. As Richard suggested 2 grams each is probably a
more realistic amount and would save money. Actually when I use a
clearing agent I make it extemporaneously using spoon measure and
discard it after the session. The EDTA and citric acid are not needed
then and the darkroom is not cluttered with jugs and tanks.
Jerry
-----Original Message-----
From: pure-silver-bounce@xxxxxxxxxxxxx
[mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Eric Nelson
Sent: Wednesday, April 05, 2006 1:18 AM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: HCA (was dichroic fog)
Yikes! I had enough problems with dichroic fog!
So would you say that using 5 gms per liter of stock
of both EDTA AND sodium citrate would be good
insurance against this calcium scum?
This is the first I've heard of this or anything
detrimental from HCA or similar formulas.
Eric
--- Ryuji Suzuki <rs@xxxxxxxxxxxxxxx> wrote:
> I flipped through Haist but I couldn't find any
> comment on the amount of
> EDTA and citrate in wash aid. They are there to slow oxidation of the
> bath, and also to prevent calcium scum. A sign of
> when you'll need them
> is when you see calcium scum on dried negatives.
>
> Also, I have some pages on my wiki on these topics.
> Just stick in
> "washing aid" or "dichroic fog" into the search
> window at the left of
> wiki.silvergrain.org.
>
> By the way when I write on wiki I'm just writing
> down as I think of
> something to add. I'm not writing something offline
> and uploading a
> finished version. So stuff changes. The frequency of
> updating and my
> level of interest are probably correlated.
>
>
>
> On Wed, 05 Apr 2006 12:15:42 +1000, "john stockdale"
> <j.sto@xxxxxxxxxxx>
> said:
> > Eric, Richard wrote the following in response to a
> question about the
> > slightly different versions that have appeared
> >
> > (I have clipped some irrelevancies, and corrected
> a slip "sulfite" to
> > "bisulfite" in the part that discusses the choice
> of meta- or bi- )
> >
> > <start of quote>
> > From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
> > Date: Mon, 5 Dec 2005 19:51:03 -0800
> >
> > ...various MSDS list either Sodium Bisulfite or
> Sodium Metabisulfite.
> > Kodak
> > Sodium Bisulfite appears to be mostly the
> metabisulfite. Evidently it
> > does
> > not matter which is used.
> > Because the formula is not published the amount of
> EDTA and Citrate are
> > not
> > firmly established. The MSDS for the concentrate
> (powder) lists the
> > amount
> > of either as 1 to 5% by weight. It disappears from
> the working solution.
> > It's possible the amount in the stock should be
> only 1 gram of each but I
> > think from Haist or somewhere I got the idea that
> it should be more.
> > Perhaps a compromise of 2 grams each should be
> used.
> > I think 15 grams of the bisulfite/metabisulfite is
> correct. In any case
> > the
> > target pH is 7.0
> > ---
> > Richard Knoppow
> > Los Angeles, CA, USA
> > dickburk@xxxxxxxxxxxxx
> >
> >
> >
> > At 11:03 AM 5/04/2006, you wrote:
> > >I've gotten tired of buying hypo clearing agent 1
> > >gallon at a time so I'm going to make a few
> gallons of
> > >it since I use so much and put in a floating lid
> tank.
> > >I just want to confirm with the list that the
> formula
> > >below is accurate as a replacement for HCA before
> I
> > >make a bunch of it. =)
> > >Thanks!
> > >Eric
> > >
> > >Stock Solution
> > >Sodium Sulfite, dessicated 100.0 grams
> > >Sodium bisulfite
> 20.0
> > >grams
> > >Sodium Citrate
> 5.0
> > >grams
> > >EDTA Tetra Sodium Salt 5.0
> grams
> > >Water to
> > >1.0 liter
> >
> >
> >
>
========================================================================
=====================================
> > To unsubscribe from this list, go to
> www.freelists.org and logon to your
> > account (the same e-mail address and password you
> set-up when you
> > subscribed,) and unsubscribe from there.
>
========================================================================
=====================================
> To unsubscribe from this list, go to
> www.freelists.org and logon to your account (the
> same e-mail address and password you set-up when you
> subscribed,) and unsubscribe from there.
>
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
========================================================================
=====================================
To unsubscribe from this list, go to www.freelists.org and logon to your
account (the same e-mail address and password you set-up when you
subscribed,) and unsubscribe from there.
============================================================================================================To
unsubscribe from this list, go to www.freelists.org and logon to your account
(the same e-mail address and password you set-up when you subscribed,) and
unsubscribe from there.
Other related posts:
