The necessity of secondary fixer ingredients

[drp]

Hi,

I've been making Bill Troop's TF-2 and TF-3 fixers which consist of using sodium thiosulfate and ammonium thiosulfate, respectively, as the main fixer ingredient. The secondary ingredients to both include sodium sulfite and sodium metaborate. If I use these fixers one shot and I'm not concerned with turning them alkaline with the secondary ingredients or storing a stock solution, wouldn't I more or less get the same fixing effect?

Thanks!

 

[Anon Ymous]

Yes, you would. You can use straight sodium/ammonium thiosulfate if you use it one shot.

 

[Corn_Zhou]

The alkali actually boosts fixing so it could work slower if you use plain hypo

 

[koraks]

The alkali actually boosts fixing

Meaningfully, so? Higher pH promotes emulsion swelling, but I don't imagine this makes all that much of a difference. The difference between ammonium vs. sodium thiosulfate will be miles bigger than any minor pH-related effect.

 

[reddesert]

The Darkroom Cookbook recommends against using a "plain hypo" (sodium thiosulfate only) fixer as the primary fixer for several reasons, including poor keeping, may produce stains, less effective. I expect these would also apply to a plain ammonium thiosulfate solution. The purpose of the other ingredients are (AFAIK) that sodium sulfite dissolves some silver halides and preserves the ionic content of the fixer, and that sodium metaborate makes it alkaline, which aids in keeping the thiosulfate ion in solution and I think promotes the fixing reaction. One would have to look at a photo chemistry book to get more details.

 

[Doremus Scudder]

Sodium sulfite is an oxygen scavenging preservative to keep the thiosulfates from oxidizing. That can fairly quickly without the sulfite (think long printing session).

The metaborate is there to make the fixer more alkaline, which helps both films and papers to fix a bit faster and, more importantly, wash faster.

The real reason to use the "secondary" ingredients is for economy. It's pretty wasteful to mix up a single-ingredient fixer at a dilution that allows full fixing (ionic content is important) in a reasonable time, then use it once and toss it after it has only reached a tenth (or less) of its capacity. I question why you would want to do that.

Best,

Doremus

 

[Randy Stewart]

Hi,

I've been making Bill Troop's TF-2 and TF-3 fixers which consist of using sodium thiosulfate and ammonium thiosulfate, respectively, as the main fixer ingredient. The secondary ingredients to both include sodium sulfite and sodium metaborate. If I use these fixers one shot and I'm not concerned with turning them alkaline with the secondary ingredients or storing a stock solution, wouldn't I more or less get the same fixing effect?

Thanks!

"Fixing" is the process of dissolving undeveloped silver halides in the emulsion, so yes, the end-result of using either primary fixer ingredient is the same. The difference is the speed of the chemical process. Sodium thiosulfate is your basic, traditional fixer, I.e. "Kodak Fixer". Ammonium thiosulfate is the primary fixing agent in "rapid fixers", commonly doing the job in half or a third of the time of a traditional fixer. Sodium thiosulfate used to be cheap as dirt. Ammonium thiosulfate has always been much more expensive.

 

[MattKing]

Sodium thiosulfate is your basic, traditional fixer, I.e. "Kodak Fixer"

For clarity, this is correct for the powder version.
The more recently found liquid "Kodak Fixer" is actually very similar to ammonium thiosulfate based Kodak Rapid Fixer, with hardener already added.

 

[Tim Stapp]

Might this be due to the new producer of Kodak Chemicals, Photo Solutions?

 

[MattKing]

Might this be due to the new producer of Kodak Chemicals, Photo Solutions?

If this is a response to my post, the liquid Kodak Fixer is very similar to Polymax Fixer, which I understand to have been available in non-USA/Canada markets for some time.

 

[xkaes]

Sodium thiosulfate used to be cheap as dirt.

It still is -- so says my wallet. And so is ammonium chloride -- to speed things up.

OK, dirt can be expensive -- especially close to downtown Las Vegas.

 

[Rudeofus]

It still is -- so says my wallet. And so is ammonium chloride -- to speed things up.

OK, dirt can be expensive -- especially close to downtown Las Vegas.

If a roll of cheap B&W film costs more than 10x the amount you pay for the fixer to process it, then cost savings become moot at some point. I've been using a Sodium Thiosulfate plus Ammonium Chloride fixer to fix prints for years, even posted a working recipe here in the articles section.

The very cheap availability of C-41 fixer concentrates and their threefold capacity over Sodium Thiosulfate bases fixers (with or without Ammonium Chloride) made me switch to rapid fixers for good. I'd use that neutral quick fixer formula of mine only if pricing or availability of rapid fixers change substantially.

 

[xkaes]

We obvious buy at different places. RAPID fixer DIES too fast -- for the price. That makes it much more expensive. Sodium thiosulfate is as close to free -- around here -- at swimming pool supply shops.

Good luck with however you do it. That might not be the best bet for everyone. It isn't for me.

 

[john_s]

We obvious buy at different places. RAPID fixer DIES too fast -- for the price. That makes it much more expensive. Sodium thiosulfate is as close to free -- around here -- at swimming pool supply shops.

Rapid fixer might be dying fast because of its low pH. That's an advantage of C-41 fixer because its pH is higher, just a shade under neutral. Unfortunately where I live C-41 fixer is harder to source at anything like its old price advantage.

 

[xkaes]

Sorry to hear you are in between a rock and a hard place. I would be too if sodium thiosulfate wasn't so cheap -- around here.