From: Richard Sullivan (richsul@earthlink.net)
Date: 02/19/03-12:05:32 PM Z
Sandy,
No color change.
All of the weak organic acid salts can be used with varying effects for pt
and pd development. In fact many show little differentiation from each other.
Some weak organic acids and their origins:
malic (malate)-- tart apples
citric (citrate) -- lemons etc
tartaric -- wine sour taste
oxalic -- bitter greens
tannic -- peat bogs
acetic -- vinegar
gallic -- oak bark and galls -- closely related to tannic
ascorbic -- Wholefoods market
formic -- ants, bee stings
I found an ad c. 1900 for citric acid in an old journal and it was listed
at better than $2.00 per lb! A lot of money in those days when oxalic was
about a nickel a pound. The main source for citric acid was citrus fruit,
thus the high cost. Today it is made from sawdust in some mysterious method
that Phillipe probably can explain. For this reason it was not used as a
developer.
The potassium or sodium salts of these can be used as developers. The
formates are violent developers and from my experience they develop all to
completion and all you get is a sheet of black paper. They may prove
interesting in very dilute amounts however.
To make, simply dilute the acid and add either sodium, potassium, or
ammonium carbonate, bicarbonate, or more dangerously the hydroxide and
being to the neutral point. pH 7.0 Carbonates give some fizz, bicarbs lots
of fizz, hydroxide no fizz but lots of heat. I used to make ammonium
citrate in 50 gal tanks by adding ammonia (a hydroxide) to a solution of
citric acid. if the ammonia was added to fast it could build up enough
internal heat to cause a violent eruption of hot liquid throwing liquid 10
feet in the air. A great big whooosh! Doubtful this could happen in small
quantities but best not to fool with the hydroxides and go with the "ates."
A face full of Draino might not be pleasant and could blind you. Safety
glasses are needed as well as good ventilation if you are using ammonia.
--Dick
11:24 AM 2/19/2003 -0500, you wrote:
>Hi Philippe,
>
>Thanks for the recipe. I had been meaning to try ammonium citrate with
>kallitype but don't have it on hand. On the other hand I have a very large
>amount of citric acid and ammonia is available everywhere.
>
>BTW, is there any color change involved in the above process?
>
>Sandy King
>
>
>
>
>>Hi Bob,
>>
>>You don't need a pH meter. You just need your nose.
>>Starting with a solution of citric acid, when agitating, pour slowly
>>ammonia in it. Step by step. At each step, if you smell above the beaker,
>>it won't smell ammonia at all. When it starts smelling ammonia, ad a
>>pinch a citric acid to neutralize the smell of ammonia. You have
>>perfectly pure ammonium citrate. (As the by-product is water).
>>You don't need to know the concentrations of ammonia neither with this
>>method,
>>
>>Cheers,
>>
>>Philippe
>>
>>|-----Original Message-----
>>|From: Bob Kiss [mailto:bobkiss@caribsurf.com]
>>|Sent: Wednesday, February 19, 2003 15:27
>>|To: ALT PHO PROC.
>>|Subject: DUMB QUESTIONS #107 & 108
>>|
>>|
>>|DEAR LIST,
>>| I have been getting great results processing my Pt/Pd
>>|prints in Ammonium
>>|Citrate and I want to continue with the same results for a
>>|show where the
>>|deadline is looming. I am running short on Am Cit developer
>>|(I top up the
>>|volume at the end of each printing session). We have many
>>|things here in
>>|B'dos but I cannot seem to find Ammonium Citrate and it is
>>|either expensive
>>|or a long wait to ship it in.
>>|Dumb Q #107: Is it possible to titrate clear ammonia from the
>>|grocery store
>>|(no soap or anything else in it, just ammonia and water) with
>>|citric acid
>>|until my blue litmus paper turns just red? Won't this give me ammonium
>>|citrate with just the slight acidity that Pt/Pd likes? Is the
>>|store bought
>>|ammonia too weak? Will this cause heating, boiling, toxic
>>|gasses, and other
>>|nasty results?
>>|Dumb Q #108: I can get Sodium Citrate which I know is another Pt/Pd
>>|developer but I believe it will yield different tones and I
>>|don't want to
>>|change horses in mid stream. If I cannot do #107 above, is
>>|there anything I
>>|can add to Sodium Citrate (I can get Ammonium Carbonate) to
>>|produce Ammonium
>>|Citrate? I was worried that Sodium Citrate plus Ammonium
>>|Carbonate would
>>|yield Ammonium Citrate plus Sodium Carbonate but that the
>>|Sodium Carbonate
>>|would leave the solution too alkaline to be a good Pt/Pd developer.
>>|****Please give me suggested volumes and masses of the
>>|ingredients. Please
>>|consider that it will be a 30 km drive here in Barbados to the
>>|nearest pH
>>|meter.
>>| So I am hoping that I can rough it suggested amounts and
>>|litmus paper.
>>| CHEERS!
>>| BOB
>>|
>>|Please check out my website:
>>|www.bobkiss.com
>>|
>>|
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