TF-3 fixer

eggshell · Dec 2, 2004

Hello,

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?

Many Thanks!

Foto Ludens · Dec 2, 2004

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:

http://www.artcraftchemicals.com/

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.

André

jim appleyard · Dec 2, 2004

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

jim appleyard · Dec 2, 2004

My recipe came out a bit out -of- order, but I think you'll get the idea.

Snapper · Dec 2, 2004

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?

mrh · Dec 2, 2004

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.

Matthew

jim appleyard · Dec 2, 2004

Yes, my reply should have said "sulfite", not "fate". I can't type, never could!

Ole · Dec 2, 2004

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

dancqu · Dec 3, 2004

Ole said:
Note that there's no chloride of any kind in TF-3.
An alternative is to make OF-1 instead, see Chemistry Recipes ;

A working strength solution of fixer has TWO capacities for film
and paper.

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

Adrian Twiss · Dec 3, 2004

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.

Adrian

eggshell · Dec 3, 2004

Thanks to all for responding. I understood what's said here on fixer dilution and fixing capacity. That was a lot of info. The most important thing I need to know is the recipe for mixing ammonium thiosulfate. I could not get ammonium thiosulfate in where I live. Shipping the a. thiosulfate solution isn't practical either. So, if someone knows how to mix a. thiosulfate from dry chemical, please help out. Thanks again!

Ole · Dec 4, 2004

I don't know of a way to make ammonium thiosulfate from dry chemicals, unless you want to go through the entire syntesis - which is long involves several smelly and/or poisonous chemicals, and gives you a solution as the result. One of the components (ammonium) is a gas which is both smelly and poisonous.

But where I live, I buy dry ammonium thiosulfate powder!

Bob F. · Dec 4, 2004

Ammonium thiosulfate does not appear to be classed as toxic for postal purposes so you should be able to buy it mail order, either in an EU country or the US, whichever is more convenient for you, and have it shipped to your location.

I'm not a chemist but I suspect Ole is correct, creating your own ammonium thiosulfate will likely be a serious industrial process so purchasing it overseas may be your only option. Or try industrial chemical suppiers in your country - you may have to buy a 25 kilo bag though...

Cheers, Bob.

eggshell · Dec 4, 2004

Ole said:
But where I live, I buy dry ammonium thiosulfate powder!

Ole, thanks again. Where do you get ammonium thiosulfate powder? How do you prepare it for darkroom work?

Thanks to Bob too!

eggshell · Dec 4, 2004

By the way Ole, do you have the formula for OF-1? How is it use? Thanks a million!

Ole · Dec 4, 2004

I buy my chemicals from VWR International which has offices in most countries around the world.

Do I have the recipe for OF-1? I should, since I made it! Look in the Chemistry Recipes section of APUG

eggshell · Dec 5, 2004

Thanks for the lead. Ole. Appreciate it!

eggshell · Dec 5, 2004

Hi again Ole,

I had a good read on the OF-1 and it seems like a very good alternative for me. I have the chemicals needed. If I understand correctly, it's fixing time is the same as TF-4 for paper & film. Is it also correct that I dilute OF-1, 1:3 to use it? Is the capacity around 30 8x10" prints/films too?

Sorry for being seemingly long-winded, but I just needed to be sure since I'm no chemist. Thanks for the patience!

Ole · Dec 5, 2004

I use it undiluted, but it works fine diluted too. It gets a little slow to my taste when diluted more than 1+1. Capacity is like all other fixers; until there's too much dissolved silver. Since I use some very unusual papers, I don't really know what that is in terms of number of prints/films.

It is slightly slower than TF-4, and a lot less smelly

eggshell · Dec 5, 2004

Thanks a lot, Ole. Best Wishes!

Helen B · Dec 6, 2004

As I understand it, the practice of adding ammonium chloride to sodium thiosulphate in solution goes back to the days before ammonium thiosulphate was commercially available at adequate purity. Pre WW2?

Best,
Helen

eggshell · Dec 6, 2004

Helen B said:
As I understand it, the practice of adding ammonium chloride to sodium thiosulphate in solution goes back to the days before ammonium thiosulphate was commercially available at adequate purity. Pre WW2?

Best,
Helen

Thanks for the additional info, Helen. Do you know if there's any advantages & disadvantages between these two types of rapid fixers?

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