Steve Anchell's book mentioned the capacity of TF-3 fixer is 20 8x10" prints or films per liter. Excuse my English & Chemistry, but
1. Is the mentioned capacity meant to be for stock or 1:4 dilution?
2. Can unexhausted working solution (1:4 dilution) be kept for use another day?
3. If I were to mix 800ml of 60% Ammonium Thiosulfate from scratch, how much of Ammonium Chloride & Sodium Thiosulfate do I need?
I'm no chemist, but I do use TF-3 with my 11x14 fiber prints, and I can tell you this: if my fixer is exhausted, it forgot to tell me or my Edwal Hypo-Chek...
I would guess, however, that Mr. Anchell was referring to the 1:4 working solution.
I do keep my working solution from one session to another, just as I did every other fixer I've used. My TF-3 has been going back to the same bottle for about a month, maybe more.
I have no Idea of how to mix Ammonium Thiosulfate, I bought a gallon from these guys:
Not at all expensive once you consider what a gallon of TF-4 would cost you.
BTW, it is stated that TF-3 fixes paper in 1 minute, but I fix for 2, partly due to habit, partly due to a half-baked test I did "clearing" a strip of paper (took 20-25 seconds to whiten from that yellowish base, so I decided to fix for at least 5 times that).
As I've said, I'm no chemist.
Yes, Mr. Anchell is referring to the 1:4 dilution.
You can use fixer over and over until it's exhuasted. I use Edwal Hypo check, but you can take the leader of the film and test it that way.
Sorry, but ammonuim chloride and sodium thiosulfate aren't in the recipe. Here's the recipe from "The Darkroom Cookbook":
Ammonium Thiosulfate 57-60% 800 ml
Sodium sulfate 60 g
I hope this helps you out.
Sodium metaborate 5 g
Water to make 1 liter
My recipe came out a bit out -of- order, but I think you'll get the idea.
I think it's Sodium Sulphite, not sulphate.
If you don't have it premixed, to mix a 60% solution of Ammonium Thiosulphate, do you mix 600g of chemical to 1000ml of water?
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I would also be very interested to know the "recipe" for the 60% solution. It is, I assume, made from a certain ratio of Ammonium Chloride & Sodium Thiosulfate plus water to achieve a 60% solution.
I use TF3 (Ammonium Thiosulfate purchased in a 60% solution), water stop for 30 seconds followed by a two fixes, each for 2 minutes. Once a piece of film takes twice as long to clear I discard fix one and replace it with fix two and make up a fresh batch for fix two. This works very well for me.
Yes, my reply should have said "sulfite", not "fate". I can't type, never could!
You can't make ammonium thiosulfate by mixing sodium thiosulfate and ammonium chloride. But you can make a mixture of ammonium thiosulfate and sodium chloride - well - not really, but something which could also be made by mixing those two chemicals.
Note that there's no chloride of any kind in TF-3.
An alternative is to make OF-1 instead, see Chemistry Recipes
-- Ole Tjugen, Luddite Elitist
A working strength solution of fixer has TWO capacities for film
Originally Posted by Ole
The first limit is the chemistry content of the solution. That is
the actual amount of A. or S. thiosulfate in the solution. Those
two chemicals are the only ones in a fix that do fix. All other
chemicals included in a fix are for preservation and ph
adjustment. The first limit is never the usefull limit.
The safe limit is the one that counts and depends on what is
being fixed. In general film and RC fixers can contain much more
silver per liter than fixers used for fiber base papers. Also
commercial and archival limits are not the same.
Get that; PER LITER. May be I've a thick skull. I read over and
over again Ilford's Rapid Fixer PDF and safe silver level data
from no less than G. Haist. It was always the same; only
so much silver per unit VOLUME.
So, the safe limit for archival results with FB paper in Ilford
Rapid Fixer working strength is 10 8x10s diluted 1:4 OR 1:9.
And that's accepting Ilford's .5 gram/liter silver safe limit.
For those who use fixer repeatedly and wish archival results
and low cost, two-bath fixing is the only way to go.
Now everyone knows why there is a film strength and a
paper strength. Dan
The TF3 recipe calls for 800ml of 60% ammonium thiosulphate. By my reckoning this is 480grams of ammonium thiosulphate in 800ml of water. You could make up a litre with 60g of ammonium thiosulphate and keep the other 200ml for another batch.
Hope this helps.