Weird sedimentation in FomaFix

miha · Nov 18, 2020

With FB papers, in order to speed up fixing and washing, an alkaline fixer is even better. Quoting PE: Swell is maximized at pH 9 and minimized at pH 4.5. Washing and fixing are best at pH 9 and worst at pH 4.5.
There is only one true alkaline fixer available off the shelf to my knowledge.

Rudeofus · Nov 18, 2020

miha said:
There is only one true alkaline fixer available off the shelf to my knowledge.

The problem with alkaline rapid fixers is their ammonia smell. You can do this in film tanks, but tray are painful. Sure, there will be heroes who'll do it anyway, but it's definitely a hard sell. Obviously you can make arbitrarily alkaline fixers if you stick to Sodium Thiosulfate.

miha · Nov 18, 2020

I'm sure we discussed this before, Moersch alkaline fixer, pH 7.5, doesn't smell. It's an odourless fixer.

Rudeofus · Nov 18, 2020

miha said:
I'm sure we discussed this before, Moersch alkaline fixer, pH 7.5, doesn't smell. It's an odourless fixer.

I believe, that pH 7.5 rapid fixer is mostly odorless. I bought a few canisters of Tetenal minilab C-41 fixer replenisher, it gives working solutions at about pH 7.5, and it is mostly odorless. The term "mostly" means: there is a distinct odor, if you smell directly above the liquid surface, but you can not smell a tray sitting in front of you.

TF-2, TF-3 and TF-4 are much more alkaline than pH 7.5, and I am firmly convinced, that these produce a noticeable smell in open trays. I still remember the smell of my initial quick fixer test formulas at too high pH.

miha · Nov 18, 2020

Based on msds available TF4 is pH 5, which doesn' look right (same for TF5).

Rudeofus · Nov 19, 2020

miha said:
Based on msds available TF4 is pH 5, which doesn' look right (same for TF5).

I talked to Bill Troop, the "T" in TF-4, about this. The MSDS is pure nonsense, the Formulary should repair this ASAP.

miha · Nov 19, 2020

Good to know, thanks. Also 15% of ammonium thio. doesn't look much. Most rapid fixers have 40% or more.

john_s · Nov 19, 2020

Alessandro Serrao said:
do you have an msds?

Yes, I keep all sorts of stuff that interests me:

Anon Ymous · Nov 19, 2020

miha said:
Good to know, thanks. Also 15% of ammonium thio. doesn't look much. Most rapid fixers have 40% or more.

Sounds about right for a working solution.

miha · Nov 20, 2020

Anon Ymous said:
Sounds about right for a working solution.

This is not the case, it's a stock.

Weird sedimentation in FomaFix

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