Fixer F24 - help

[Ricardo Maydana]

boys a help, I usually use Formula F24 fixative, only this time I get sodium metabisulfite, instead of sodium bisulfite. Can I use the same ratio of metabisulfite in formula F24?

[Alan9940]

I do and never had an issue.

[Ricardo Maydana]

I do and never had an issue.

hello, thanks for your answer, saying that what is the formula you use? You can share. Thank you.

[koraks]

this time I get sodium metabisulfite, instead of sodium bisulfite.

Odds are you usually get metabisfulfite when you purchase bisulfite. You can replace bisulfite with metabisulfite in your formula by using roughly 0.9-0.95 as much metabisulfite as the amount of bisulfite called for. In water, metabisulfite instantly becomes bisulfite. For all intents and purposes, in a fixer formula, you can just use as much metabisulfite as the mount of bisulfite specified; the little amount of excess resultant bisulfite will not influence the fixer in any significant way.

[Ricardo Maydana]

Thank you very much for the clarification and just to not make a mistake, since English is not my mother tongue.

if I did not understand, you can replace the bisulfite with the metabisulfite, at 0.90, below I write the formula I use and how it is if I use metabisulfite.

If I use an amount of 30 g of bisulfite in my form, I must use 27 g of metabisulfite. is it like that?

My formula.

water 750 ml
sodium thiosultate crystaline 240 gr
sodium sulfite 20 gr
sodium bisulfite 30 gr
para preparar un litro de solución.

[koraks]

Yes, that would work, and if you kept the metabislufite at 30g it woud still work fine as the amount is not critical in a formula like this.

Out of curiosity: why use a sodium thiosulfate formula instead of a rapid fixer (ammonium thiosulfate)?

[Ricardo Maydana]

I use that formula for paper is the Kodak f24. I never question change, I get used to that formula.

[Alan9940]

Hello Ricardo,

The F-24 formula I use is slightly different from yours:

Water 750ml
Sodium Thiosulfate, penta 240g
Sodium Sulfite 10g
Sodium Bisulfite 25g
Water to make 1L

As I said above, I many times substitute Sodium Metabisulfite at 25g, though...technically...you would multiply by 0.91 bringing the total of metabisulfilte to approx 23g. I don't worry about it and use those chemicals interchangeably.

[Ricardo Maydana]

Thank you. if it is something different. I see you try according to your indications. following the line of Fixer f24. Is it the same formula for film?


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[Alan9940]

Thank you. if it is something different. I see you try according to your indications. following the line of Fixer f24. Is it the same formula for film?


Enviado desde mi iPhone utilizando Tapatalk

I looked it up in the The Darkroom Cookbook and the version I use is what's listed in that reference. You can substitute 22g of citric acid for the bisulfite, if odor is a problem for you. Yes, I use the same formula for both film and paper. If you intend to tone (selenium) your prints, then use this formula for the first bath, followed by plain hypo for the second bath.