Ole's Fixer Formula

[john_s]

I was wondering if Ole has made any adjustments to his fixer formula. I have from a previous APUG post (copied and pasted):
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<start quote>
200 g Sodium Thiosulfate pentahydrate
40 g Sodium sulfite
EITHER 15 ml 10% Sodium metabisulfite solution
OR 15 g sodium bicarbonate

Add 50 g Ammonium chloride last - even better if it's diluted in 100ml water first.

Bicarbonate is more easily available, but should not be used if there is any possibility that the paper/film might be - or become - acidic. The metaborate version can be used with acid stop bath (citric acid), the bicarbonate not.
<end quote>
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Am I correct in assuming that the "metabisulfite" should read "metaborate"? Or is metabisulfite to make it slightly acidic?

I use Agfa FX-Universal at present (pH=7.2), and will continue as long as the local branch of Agfa continue to supply it in a convenient size. But just in case they stop, I need an alternative.

 

[dancqu]

That bisulfite is acidic though I can't imagine 1.5 grams will have
any effect on that fixer's ph. That 40 grams of sulfite will push
the ph up to, I'd guess, 8 to 9. Bicarbonate is an alkali. Dan

 

[Ole]

Am I correct in assuming that the "metabisulfite" should read "metaborate"? Or is metabisulfite to make it slightly acidic?

You are completely correct. I "fixed" that in the Chemistry Recipes section...

A quick test with an aging pH strip shows that the pH of the fixer (both versions) is between 8 and 9, closer to 8. My target was 8.3, though I can't remember why. I think I've hit that target, at least with the chemicals I currently use - and local tap water which is acidic.