Clarification needed re "Odorless" Fixer vs Standard Sodium Thiosulfate Fixers
I'm looking for a less smelly and sick-making (nausea) fixer than ammonium thiosulfate (aka rapid fixer), and in looking at the available odorless options, I realized they're basically old hypo/sodium thiosulfate formulas ( e.g. Arista's). Are these fixers basically the same as Kodak's old powder fixer (e.g. http://www.freestylephoto.biz/197174...ake-1-Gallon)? Here are their ingredients:
70 - 75
10 - 15
Ammonium alum, dodecahydrate
5 - 10
1 - 5
SODIUM THIOSULFATE 70-80
SODIUM METABISULFITE 5-10
Other than the hardener in Kodak, it's the same fixer, right? Or is the Arista really less smelly and fumy? I'm asking because I can get the Kodak locally but the arista and others like it have to be shipped and are thus much more expensive. Also, would just using Sodium thiosulfate w Sodium Bisulfite a la Michael and Paula be more or less smelly than the above options? Thanks for your help,
No, the Kodak fixer is a Rapid Hardening fixer not recommended these days, the second is a plain acid fixer very much slower working.
The best fixers are Ilford Rapid fixer or Hypam, very economic no odour, slightly acidic pH 5.2 - 5.4. Kodak make an equivalent.
If you don't like the ammonia smell stay away from neutral/alkaline rapid fixers.
Are you sure these are not the same, the ingredients are identical except for the hardener? Also, I thought ammonia-based rapid-fixers are the smelly ones, and acid, whereas the 'odorless' variety are alkaline, or neutral. Or did I misunderstand?
Ammonium Alum and Sodium Thiosulphate form Ammonium Thiosulphate - the alum is the hardener the metabisulphite adjusts the pH to the required acidity for the hardening to occur.
That's why the Kodak fixer is a Rapid hardening Fixer.
Alkaline fixers give off ammonia, odourless are the acidic side of neutral, and depend on heavy buffering to prevent them turning alkali.
I use Silvergrain Clearfix Neutral in trays for my prints. I think it has since changed names to Eco-Pro. As much as I like TF-4, I cannot stand the amonia smell, this is odorless. I do my printing in a room with limited ventilation and cannot smell it at all.
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i use the eco pro neutral fixer. it's a good product, rapid and low odor. contains ammonium thiosulfate and sodium sulfite.
Thanks for the clarification, Ian. One more question, what kind of fixer is Tetenal's Superfix Plus? I can't find any info online about its ingredients, and that's what I've been using so far. Thanks.
Thus be sure to use an acidic stop bath (with alkaline developers) to protect the fixer.
Originally Posted by Ian Grant
Very true, I think you'll find all those involved on Photo chemistry on the forum recommend using an acid stop bath with an alkaline fixer. There's a number of eminent photographers who had dichroic fogging of films without one.
Originally Posted by Monito
I'm not eminent, far from it, but I was basing the comment on the idea that when acidic ammonia salt fixers go alkaline, they start to smell. The acid of the stop bath neutralizes the developer, which tends to be alkaline (except for things like coffee & ascorbic acid developers), then goes further to make the film acidic. Then the acidic film and clinging drops go into an acidic fixer and all is well.
Originally Posted by Ian Grant
That's my understanding of a desirable chemistry, but probably I'm missing something if you recommend an acid stop bath with an alkaline fixer.