[pure-silver] Re: OT-- chroma list
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Sat, 25 Feb 2006 20:40:55 -0800
----- Original Message -----
From: "Stein" <rstein@xxxxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Saturday, February 25, 2006 4:23 PM
Subject: [pure-silver] Re: OT-- chroma list
MessageDear Dave,
Today's posting on the Pure Silver - Chroma list
concerns enormous good fortune with a sting in the tail.
I bought a cubic yard of Jobo tanks from a eBay sale
last month. They are the 2500 series and were used to run
B/W processing in a Sydney commercial lab. I guess most of
them were used in the rotation mode, but 3 seem to have been
set on end and used as deep dip tanks or washers. Hard to
say, but the end result on the roataion ones has been a
silvery-black deposit on the interior of all the components
while the vertical ones have a spectacular encrustation of
old fixer on the outside.
I have wiped most of the silvery gunk from the tanks but
wondered if minute residues will affect their use in a C 41
process. Any ideas, people?
And as for the fixer crud - I think the tanks will be
fine if I can get it off. Will conventional acids like
hydrochloric or sulphuric do it or do I need to go more
exotic?
Uncle Dick
Plain household bleach should remove the fixer. Silver
can be removed by a dichromate or permanganate bleach, both
of which require sulfuric acid to make up. Some silver
deposits are very difficult to remove and must be scrubbed
off using something along the lines of a stiff toothbrush.
Mild silver stains can sometimes be removed by strong
Farmer's Reducer or by using a bleach made up of film
stength rapid fixer with about 15 grams per liter of Citric
acid added.
Kodak TC-1 Tray Cleaner
Water 1.0 liter
Potassium bichromate 90.0 grams
Sulfuric acid, concentrated 96.0 ml
The usual warning, add the acid slowly to the water to avoid
heating and splattering.
This solution can be re-used until it stops working.
Kodak TC-2 Tray Cleaner (Especially recommended for removal
of silver stains)
Solution A
Water 1.0 liter
Potassium Permanganate 5.0 grams
Sulfuric Acid, concentrated 10.0 ml
Solution B
Water 1.0 liter
Sodium Bisulfite 10.0 grams
Sodium Metabisulfite will do.
For use pour A into the tray and swirl around for a few
minutes. Then pour out and rinse with water. Then pour in
Solution B to remove the stain left by the Permanganate,
then pour out and wash thoroughly.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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