Now for my question. After all of this experimentation I'd like
to understand what difference different types of bleach does
to the toning. I only know of pot ferri, and I get it from the
Kodak sepia toner packages. - Thomas
Perhaps Rudman's book is at your local library??? It is worth buying however.
Put it on your X-Mas list. Surely Santa visits your house!
Hi Thomas, the cupric sulphate bleach I am using
is like the first variant given by CBG, but instead of
sulphuric acid I am using sodium hydrogen sulphate
(sodium metabisulphate, sold as "Dry Acid" ...
My bottle of the granulated is marked sodium bisulfate.
A pyro may be made of it by heating; the meta?
As I've mentioned there is the bleach then what follows.
All of the bleaches are oxidizers. FerrrIcyanide converts
the silver image to silver ferrOcyanide. Although no one
has taken credit for testing, I believe that the silver
ferrOcyanide image can be toned. No halide or ???
needed.
Thomas,
Were you mixing the Kodak Sepia II and Selenium together to use them as a single solution or using them separate sequentially?
And in what strength were you using them? Any detail you can add would help people make use of your interesting combination.
Thanks!
C
A couple of cupric / copper based bleaches I have "harvested" off the internet follow.
I have not used them so proceed with appropriate caution.
------------------
Cupric Sulfate Bleach from Ann Clancy A bleach for redevelopment.
Cupric sulfate (Copper Sulfate) 50g
Sulfuric Acid concentrated* 6.5 mL
Sodium Chloride 100g
Cold water to 1000 mL
always add acid to water
-------------------------------
PE offers a information on copper based bleaches:
my same caution applies (though in this case, PE is a sterling source).
Bleach Baths from Cupric Sulfate
Variation A
490mL Distilled Water
5g Cupric Sulphate
10mL Sulphuric Acid (98%)
Variation B
490mL Distilled Water
10g Cupric Sulphate
25g Potassium Hydrogen Sulfate
Variation C
490mL Distilled Water
5g Potassium Dichromate
10mL Sulphuric Acid (98%)
Cupric Sulfate is a well known bleach for films. There are many patents on it in the literature. I have worked with it myself. The problems are threefold; the first is that the bleach will not work if there is not enough acid, and the second is that the copper salts can stain the film or paper and cannot be removed and the third is that these bleaches are very slow in most cases. There are also blix formulas.
Concentrated sulfuric acid (Oleum) is pretty much unobtainable. You can get dilute sulfuric acid at auto stores (about 37%) and from the Formulary (about 48%). The 48% is the highest that can be shipped now in the US without a special license.
A drop of oleum on the skin does not cause immediate burns due to lack of water. It needs water to react. So, immediately start a huge flow of cold water in the nearest tap and wash it off as quickly as possible with as much water as possible. Do not leave it on the skin for over 30". When you wash it off, you will feel an instant burning sensation and a lot of heat, as the reaction starts. If you wash with enough water, fast enough, no harm will be done in most cases. Once rinsed well, put some sodium bicarbonate on the affected area for about 1/2 minute and then re-rinse in cold water. If the skin is broken, call a doctor or go to emergency immediately. Do not get it in the eyes.
PE
-----------------------------
Another bleach of origin I did not record:
Water (40°C) 750 ml
Copper sulfate 50 g
Sulphric acid (10%) 65 ml
Sodium chloride 50 g
Water to make 1000 ml
---------------------
C
Could be that the toning of the 'ferrO' image does
not give good results. BTW, what other than sulfur
and selenium will give good results toning the 'ferrO'
or rehalogenated image? Dan
The thiocarbamide sepia toner acts incredibly quickly,
toning a print in 15 - 20 seconds (due to the presence
of the hydroxide ion? Possibly).
The selenium was a bit problematic, it does tone the the
silver, but I remember getting a lot of leaching of the toned
silver from the image, leaving a weak image, and murky
toner. Possibly due to ...
Possibly due to the fixer in that selenium toner? Silver ferrOcyanide is NOT a least soluble salt of silver.
I've some P. ferrI. and sodium sulfide and will run some paper through with and without a halide post treatment. There are
likely other salts of silver which could be tested. Dan
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