re using sodium thiosulfate

hi all,

i know that sodium thiosulfate is pretty cheap....BUT...can i re use it? for how long? will my "fixer checker" stuff tell me when it is bad? how long will it keep if i pre mix it?

i just get tired of mixing it and dumping it. re: film and prints.

thanks

eddie

eddie gunks said:

hi all,

i know that sodium thiosulfate is pretty cheap....BUT
...can i re use it? for how long? will my "fixer checker"
stuff tell me when it is bad? how long will it keep if i pre
mix it? i just get tired of mixing it and dumping it.
re: film and prints. thanks eddie

Click to expand...

Your fixer checker will do. Add sodium sulfite for
longer life. The fix will be alkaline.

I use the stuff very dilute, one shot, fresh at processing.
Straight S. Thio.; nothing added. Each roll, each print,
a use then down the drain. No bottling, no testing,
no stop, no worry. Any off the shelf fixer can be
used the same way.

Check this NG for Ansel Adams plain fixer. Dan

If you make up TF-2 fixer then it's reusable. Plenty other Hypo based formula that can be reused but TF-2 is pretty simple.

http://www.jackspcs.com/tf2.htm

If you just use hypo it won't keep. You have to add at least the sodium sulfite.

You could even save a bit more if you would use the cascade fixing technique.

From a theoretical perspective it would even enhance the qualitiy of fixing.

AgX said:

You could even save a bit more if you would use the
cascade fixing technique.

Click to expand...

From my one reading that is how AA did use his
plain fix; as a second fix. There is no reason not
to also use it as a first. Two bath fixing, much
recommended. The second bath has a low
silver load. I've read of three baths. Dan

Thanks everyone!

what dilutions do you use for a "dilute" mixture? i am just curious how far it will go.

thanks for the link.

eddie

Cascading Fixation

I find this issue quite complex and quite some procedures could be thought of.
I give two different cascading procedures for discussion:

First as a rule of thumb you measure by sight the clearing-time (time for the halide to dissolve in fresh stock) for the film in question.

2 X clearing-time = fixing time

When the clearing time has doubled in the stock under use, it should be discarded. This common rule is considerd by others to bring the fixer beyond its capacity but to be used for the first bath in a two-bath process.
Alternatively one can measure the Ag concentration and use a threshhold of ones like.
(Think also of the potassium-iodide test.)


-) procedure 1

Make two fixing baths, use them consecutively each for the standard fixing time.

Discard the first bath and make the second the first, when the second yields a clearing time twice the original, or when the first does not clear. Whatever is first.

This is the most economical. It should yield a better quality than reusing the bath in a single-bath process (which is controlled by the doubled-clearing-time method).


-) procedure 2

Make two fixing baths, use them consecutively each for ½ fixing time.

Discard the first bath and make the second the first, when the second yields an Ag concentration less than the one of a bath considered of being exhausted.

By this you will use a quite fresh bath as second bath, but instead of discarding it as in a single-bath single-use process you are re-using it (as first bath) after a short use and thus be a bit more economical.

thanks agx,

how do i determine my clearing time?

cheers.

eddie

Print or film fixer is the same: put a sq inch of junk undeveloped film in fresh fixer - time it - mine clears in 30 seconds.
After each printing session - or 20 8x10 or 20 rolls of film - I test - if it takes more than 45 seconds to clear - It gets pitched - If it takes more than a minute to clear - I will also likely re-fix what I was working on.

eddie gunks said:

thanks agx,

how do i determine my clearing time?

cheers.

eddie

Click to expand...

Just cut a piece of your undeveloped film, a piece of the leader would do, put it in your fixer and wait until the opacity will go and the film base will be transparent.
This should do for many film types. Types with colloidal silver, etc. antihalo-layers and such will of course keep some opacity in that test. But I guess you got the idea.

The time it takes to get the film transparent will be the clearing time for that film and that fixer bath.

eddie gunks said:

Thanks everyone! What dilutions do you use for
a "dilute" mixture? I am just curious how far it will go.

Click to expand...

It's pretty much of a case of so much silver, so much fixer.
Very quantitative. As long as the solution has enough chemistry
to complex all the silver to a soluble state then the volume of
the solution is of no factor.

I've put a few rolls of 120 through at 1:31; 500 ml solution
volume, rapid fix concentrate. For the same volume and
most films I suggest 1:24.

I've been doing some proofing on 5x7 Slavich Graded SW
using a 1% solution of 140ml volume; S. Thio. at a 1:15
dilution. Of four papers I've tested the Slavich takes the
least amount of fixer; Kentmere Bromide about 2/3
more. Papers and films present varying loads
upon fixers.

I do not recommend roll counting or square footage
be a measure of the state of the fixer save for those
experienced in what is going on. Test the fixer itself
but not for it's silver content. Test for it's remaining
capacity to fix. I've not been able to fault the film
strip test and it's measure by time to clear. Dan

AgX said:

(Think also of the potassium-iodide test.)

Click to expand...

I just realized that this test is said not to work with rapid-fixer. One has to resort to Ag-indicator-paper then.

dancqu said:

Your fixer checker will do. Add sodium sulfite for
longer life. The fix will be alkaline.

I use the stuff very dilute, one shot, fresh at processing.
Straight S. Thio.; nothing added. Each roll, each print,
a use then down the drain. No bottling, no testing,
no stop, no worry. Any off the shelf fixer can be
used the same way.

Check this NG for Ansel Adams plain fixer. Dan

Click to expand...

I think Haist makes the observation that highly diluted fixers don't work, or work well. Not enough spare molecules floating around hunting silver.

What is your formula? Have you checked for residual silver? Why not add a bit of sodium sulfite, at least for paper?

dancqu said:

I've put a few rolls of 120 through at 1:31; 500 ml solution
volume, rapid fix concentrate. For the same volume and
most films I suggest 1:24.

I've been doing some proofing on 5x7 Slavich Graded SW
using a 1% solution of 140ml volume; S. Thio. at a 1:15
dilution. Of four papers I've tested the Slavich takes the
least amount of fixer; Kentmere Bromide about 2/3
more. Papers and films present varying loads
upon fixers.

Click to expand...

Uh, I thought this thread was talking about straight, or with sodium sulfite, "hypo." I thought you use hypo straight and weak. Now I see dilutions of prepared fixers in this posting.

Are you saying that you use 1:24 dilution of a prepared stock fixer instead of, say, 1:4 as is typical?

Not my films!

AgX said:

I just realized that this test is said not to work with
rapid-fixer. One has to resort to Ag-indicator-paper then.

Click to expand...

This is expanding upon the last paragraph of my post 11.

The potassium iodide test is a test on the fixer it self and
of it's reserve capacity. It should be a valid test. How to
precisely conduct the FT-1 test? Kodak's procedure for
conducting the test, at least in my mind, could be
more clear. Various off the shelf offerings vary
in their approaches.

Film fixers can handle a lot of silver. The paper test will
need to indicate in the multi-gram region in order to tell
how loaded is the fixer with silver. BUT ....

As I've mentioned in post 11 a test for silver levels is
not a test of remaining capacity. As mentioned I've not
been able to fault the film strip test.

So the the iodide test is good in principle. If only it
were standardized. Silver level tests do not indicate
remaining capacity. Roll counting and square footage
methods are the least reliable. Dan

As far as I understand the iodide test is conducted in such a manner that depending on the quality requirements to your fixing bath the amount of potassium-iodide solution dripped into to the bath sample is chosen (the higher the requirements, the more iodide).

The test with indicator paper is conducted that way that you interprete the given result of Ag-concentration to the type of bath, the type of emulsion, as well your archival requirements. Which means that for this test you have to know the chemistry of your emulsions and of your fixer and and thus its `reserve´.

Dan,
I have not given this whole issue much thought up to now, thus please correct me if you think I’m wrong.


Furthermore, what about employing an additional fixing bath after a process of fixation believed to by suffucient (by any means whatsover)? This additional bath could complexate to the limit any residual un- or unsufficiently complexated halides and still stay fresh for a long time.

AgX said:

As far as I understand the iodide test is conducted in such
a manner that depending on the quality requirements to your
fixing bath the amount of potassium-iodide solution dripped
into to the bath sample is chosen (the higher the
requirements, the more iodide).

Click to expand...

Likely Kodak's FT-1 test with iodide is today's standard if
any although probably not the first. For all I know the FT-1
test itself may go back seventy or more years. To read of it's
method of application search Google for, FT-1 Kodak. Kodak's
method is not the method you've described.

I've a bottle of Rexton Fix A Sure. Another method of testing.
For myself and for a short time I used yet another method of
my own devising. So where is a standard and measures for
determining the results of the test? The iodide test could
be a good test were it standardized and quantified. Dan