Sodium Thiosulfate Fixer Formula

dancqu · May 3, 2007

Ryuji said:
Dan,
"I feel that you are trying to convince me something but
without addressing the concerns I described above."

The ONE concern is the end product however it's arrival.
Ilford proved that years ago with it's Archival Processing
Sequence. At start they claimed a mix of 40 8x10s could
be pushed through a liter of 1:3 rapid fix; their one minute
film strength for paper fix. The very short fix + the 5-10-5
wash, hca, wash, comprised the sequence. Although the
one fix loads to Ilford commercial processing levels,
2 grams/liter, the 5-10-5 follow up turns out a
product which meets ANSI archival levels.

So the end product meets archival standards but the
processing does not come close. That procedure BTW
no longer exits as an archival sequence. Long LE is now
tied to a 0.5 gram/liter maximum silver level. For what
that says. I think the 'sequence' for archival results
ran into some in the field difficulties.

"Existing published data show rapid decline of fixing rate
below about 0.8M of thiosulfate..."

My estimate is an eight fold increase in time in the fixer;
four minutes with sodium thiosulfate 1% concentration.
That four minutes though is still less than that for
a two-bath fixer.

"Dilution by carryover fluid ..."

Who needs it? One more concern I do without and do so
by using the fix once then down the drain with it. Dan

Ryuji · May 4, 2007

dancqu said:
So the end product meets archival standards but the
processing does not come close. That procedure BTW
no longer exits as an archival sequence. Long LE is now
tied to a 0.5 gram/liter maximum silver level. For what
that says. I think the 'sequence' for archival results
ran into some in the field difficulties.

Ilford system needs rather precise execution of the procedure, but when done properly, it works very well. You mentioned 0.5g/L silver level but that's not in the current ISO standard. The actual values in the current ISO is 10x higher than that value.

dancqu · May 4, 2007

Ryuji said:
Ilford system needs rather precise execution of the procedure,
but when done properly, it works very well. You mentioned 0.5g/L
silver level but that's not in the current ISO standard. The actual
values in the current ISO is 10x higher than that value.

I've doubts the word archival should be applied save to the
finished product per my previous post. That's where it counts.
A processing which, when All is said and done and measured by
end product tests which show some archival standards be meet,
can be termed archivally processed. For pre-packaged users it is
the suppliers responsibility to provide the necessary guidelines.
So, it is assumed by users of off-the-shelf chemistry that the
work has already been done. Like I always say, follow the
instructions on the package. Dan

Bob Carnie · May 12, 2007

I am trying to switch from Manufacture Rapid Fix to a home brew solution.
We use huge volumes of dev , fix, hypo clear at our shop.
The formula I am having trouble getting my head around is a Rapid Fixer as this thread shows.
I respect both Ryuji and Dancqu knowledge and would appreciate if one of them could help me with a workable formula for my methods. Here is my sequence right now using Rapid Fix.

dev 3min, acid stop 30secs, first fix 1 1/2min second fix 1 1/2 min, wash 5min, kodak hypoclear 1:4 5min, wash 25min in vertical washer.
Toning is after final wash unless selinum which is then right after hypoclear.
I am thinking of the following formula for a Rapid Paper Fix.

working solution
Water >700ml
Ammonium thiosulfate, 57-60% > 185ml
Sodium sulfite anhydrous > 12g
Acetic acid glacial >9ml
Boric Acid > 7.5g
water to make 1 litre.
* this is taken directly from The Film Developing Cookbook, Stephen G Anchell Bill Troop*
would this work for my current workflow as described above for a Rapid Paper Fix using the times I have listed.
thanks
Bob

dancqu said:
I've doubts the word archival should be applied save to the
finished product per my previous post. That's where it counts.
A processing which, when All is said and done and measured by
end product tests which show some archival standards be meet,
can be termed archivally processed. For pre-packaged users it is
the suppliers responsibility to provide the necessary guidelines.
So, it is assumed by users of off-the-shelf chemistry that the
work has already been done. Like I always say, follow the
instructions on the package. Dan

dancqu · May 12, 2007

Bob Carnie said:
Here is my sequence right now using Rapid Fix.

dev 3min, acid stop 30secs, first fix 1 1/2min second fix 1 1/2 min, wash 5min, kodak hypoclear 1:4 5min, wash 25min in vertical washer.
Toning is after final wash unless selinum which is then right after hypoclear.
I am thinking of the following formula for a Rapid Paper Fix.

working solution
Water >700ml
Ammonium thiosulfate, 57-60% > 185ml
Sodium sulfite anhydrous > 12g
Acetic acid glacial >9ml
Boric Acid > 7.5g
water to make 1 litre.

* this is taken directly from The Film Developing Cookbook, Stephen
G Anchell Bill Troop*
would this work for my current workflow as described above for a
Rapid Paper Fix using the times I have listed. thanks Bob

That working strength is very nearly a standard film strength
1:4 dilution. Film strength has great silver capacity due to the
gross amount of A. Thio present. That concentration is possible
with film because film has a considerable tolerance for high silver
levels per unit volume of fixer. So, film strength fixers.

I think Ilford years ago started the quick 1 minute fix in film
strength routine. It made possible their quick wash sequence.
In a nut shell that quick fix and the short wash sequence are
the quickest way to a finished FB print and no more. I've not
checked all the fixers on the market but think many other
labels have jumped on the film strength bandwagon. Not
Kodak, film 1:3, paper 1:7.

What it boils down to is this: At film concentration a liter
of working strength fixer can be loaded with much more silver
than any FB paper should ever encounter. Ilford mentions 2
grams/liter for commercial paper, 0.5 grams/liter for great
LE. Film may go as high as 8 to 10 grams.

With the two bath method being used and according to Ilford
the first fix may go to 1 gram, 20 average exposed 8x10s, using
paper strength. Twice that, 2 grams or 40 8x10 at film strength.
Film or paper strength, two baths make for great LE. Work flo
permitting 1:9 may result in chemistry savings.

The formula looks OK to me. A little preservative and a
modest amount of ph modifying/buffering. Nothing for
hard water. My guess, a near neutral fixer. Dan

Bob Carnie · May 13, 2007

Thanks Dan
I will move forward with this formula.
Bob

Ryuji · May 16, 2007

Bob, in your formula, acetic acid and boric acid are unnecessary unless you are using a hardener. I suggest to omit them. Acetic acid is known to slow down the washing process, and boric acid is toxic to plants. Instead, you can use 15g sodium sulfite and 5 to 15g of sodium metabisulfite to make the fixer neutral to mildly acidic pH.

The tolerance for silver concentration in fixer solution has been updated a few times in past few decades. The most recent guideline is in the latest ISO standard mentioned in this thread. It's also referenced on my website (just search on my wiki site). I recommend you go ahead with the above modified formula and follow the standard processing capacity.

Bob Carnie · May 16, 2007

Folks
This is why I love APUG, though I have been printing for 30plus years there is always something to learn. Simply ask the question and there always is someone willing to help.
Thanks to Dan and Ryuji I can move forward with a home brew and save my self self doubt .

Ryuji said:
Bob, in your formula, acetic acid and boric acid are unnecessary unless you are using a hardener. I suggest to omit them. Acetic acid is known to slow down the washing process, and boric acid is toxic to plants. Instead, you can use 15g sodium sulfite and 5 to 15g of sodium metabisulfite to make the fixer neutral to mildly acidic pH.

The tolerance for silver concentration in fixer solution has been updated a few times in past few decades. The most recent guideline is in the latest ISO standard mentioned in this thread. It's also referenced on my website (just search on my wiki site). I recommend you go ahead with the above modified formula and follow the standard processing capacity.

Sodium Thiosulfate Fixer Formula

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