From: Philippe Monnoyer (philippe.monnoyer@skynet.be)
Date: 02/19/03-08:33:29 PM Z
All right. I quickly made an excell sheet at
http://users.skynet.be/philippe.monnoyer/amcitrate/amcit.xls
This should answer these questions on quantities. There may remain errors
though, I didn't check it. It's late here and I'm going to fall asleeppppp
...rrrr........
Philippe
----- Original Message -----
From: "Sandy King" <sanking@clemson.edu>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Wednesday, February 19, 2003 11:27 PM
Subject: RE: DUMB QUESTIONS #107 & 108
> There is one thing about the recipe I did not understand. If you make
> the ammonium citrate following Philippe's recipe, what percent
> solution of ammonium citrate do you wind up with?
>
> Sandy King
>
>
>
>
>
>
>
> >Yes,
> >
> >Philippe is correct.
> >
> >I might also add that ammonium citrate is strongly buffered and this
> >might cause some confusion when making it.
> >
> >
> >What happens is as you add ammonia the pH will gradually go up step
> >by step more or less linearly to the amount of ammonia being added.
> >When you get to 6.5 it will stop moving and at that point you can
> >add a quite a quantity of ammonia without seeing a move in the pH
> >and then suddenly the pH will start to move up again. It's a slope
> >up, a flat spot and a slop up. As most paper will be alkaline today
> >it is best as Philippe says to be on the acid side of the buffer
> >point. Ammonium citrate is nice in this regard as it holds it pH
> >pretty steady due to the buffer action. Philippe has a far more
> >knowledge of chemistry than I do so if I've not explained this quite
> >right my apologies.
> >
> >--Dick Sullivan
> >
> >At 03:42 PM 2/19/2003 +0100, you wrote:
> >>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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