[pure-silver] Re: Formula #87 in Anchell
- From: Jean-David Beyer <jeandavid8@xxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Mon, 16 Jan 2012 21:28:00 -0500
Bogdan Karasek wrote:
> Hello all,
>
> Just needed some advice from those who know about such things....
>
> More and more, I find myself mixing my own chemicals. For paper, I can
> now get Hypo (Sodium Thiosulfate) in 25kg bags from a chemical firm. I
> use the 2 tray method of fixing. But what about film? I checked
> Anchell and found this interesting formula (#87 Odourless Acid
> Hardening Finishing Bath for film or paper)
>
> I have all the ingredients:
>
> Sodium Thiosulfate, 240gr
> Sodium sulfite (anhydrous), 15.0gr
> Acetic Acid 28%, 48.0ml
> Balanced Alkali, 15gr
> Potassium Alum, 15gr
> Water to make make one Litre.
This is exactly the same as Kodak F-6 that I use for both film and
paper. A rapid fix is better for TMax films than this, although it will
work for that too.
I mix it with half the alum for paper, and will be omitting the alum
altogether in the near future. The alum in question is Potassium Alum,
Fine Granular (dodecahydrated).
>
> I don`t have any Potassium Alum , but Anchell tells me that the
> Potassium Alum is the hardening agent in the solution, so if I leave it
> out, do I have a fixer that is non-hardening?
Yes.
I know modern films, such as TMax, do not require hardening if you keep
your solution temperatures under 100F or thereabouts. Older films may
need it. I suspect Tri-X and Plus-X do not require much, if any hardening.
> Am I correct in this assumption and can I proceed without the Potassium
> Alum. I will be mixing 17 Litres in tanks for 8x10 Tri-X.
>
> Later, I want to develop some 4x5 Efke PL 25 Otho. The Efke emulsions
> tend to be soft and a hardening fixer is recommended.
That is my understanding too. I have never used any eastern European
films. I have had good results with Ilford film and some of their papers.
>
> Is there a commercial name for Potassium Alum, something I could get at
> the pharmacy or supermarket, so I could use it with the Efke fixer, or
> am I still good without the Alum?
Potassium Alum is the commercial name for the stuff. Chemists know it as
potassium aluminum sulfate dodecahydrate
>
> Can I substitute Baking Soda for the Balanced Alkali, and if so, in what
> proportion, or are they interchangeable in terms of quantity?
No. You might consider making Kodak F-5 fixer if you cannot get Balanced
Alkalai. Kodalk, as it is known commercially, is sodium metaborate. I
cannot tell if it is hydrated with 4 molecules of water or 8, but it may
not make much difference. F-5 uses 7.5 gram of boric acid fine crystals
instead of 15 grams of Kodalk. Some people do not like the smell of F-5,
although I do not find it objectionable. If you are going to leave out
the alum, you could probably cut the acetic acid in half or, if you are
very sure your stop bath is adequate, leave the acid out entirely.
>
> Cheers,
> Bogdan
>
>
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