Why acid fix?

[Donald Miller]

Hardners are basically used only in the fixing baths of film (they harden the emulsion and reduce the chance for physical damage). In fact, the use of hardner in print baths will affect the toning ability of a print.

[Robert]

I think for modern films it isn't an issue. Maybe if your processing the film in warmer then normal temps then a hardner might help? I'm just using TF-2



Sodium Thiosulfate 250 g
Sodium Sulfite (anhy) 15 g
Sodium Metaborate 10 g
Distilled water to make 1000 ml

Keeps fine. At least I end up dumping it and it's still fixing pieces of film.

Which reminds me I need to make fix-))

[MikeK]

I believe the use of an acid hardening fix was mainly used for films where the gelatin overcoats were very soft. In fact some old books recommended formalhyde to toughen the coat (as do some current E6 processes). Packaging I suspect is the main reason for an acid fixer being used for film and paper. I believe Kodak produces the only fixer (liquid) where you get two bottles, one with fixer and the other containing the hardening solution.

I am a firm believer in the use of plain fix (Hypo and Bisulfite) for my prints and films or an Alkeline fix for film. Works just fine and eliminates chances of staining when toning.

Mike

[David A. Goldfarb]

Zonal Pro fixer also comes in two bottles, but unlike Rapid Fixer, you can buy them separately, so you don't need to pay for the hardener, if you don't want it. That was my regular fixer until I switched to TF-4.

[Ole]

Hardening was also mentioned in the Vogel book, as something to be used "in very warm weather". It was a "standard" alun hardener.

His film fix was plain hypo with sodium bisulfite, with hardener as an optional extra for those days when the emulsion wants to slide straight off the glass plate...


If anyone wants recipes for vintage developers, I have them all...

[Donald Miller]

OleTJ, Does your book contain a developer formula for 777? This is a developer that Ed Buffaloe has addressed on his web site.

[Robert]

Going back to the original question. Could it be for the smell? Sort of like if it smells it must work? I don't think my fixer smells at all. The lack of smell made me wonder if it was okay. I could see this being a marketing problem.

[fhovie]

I use TF-4 which, I understand is slightly basic. The struggle is -- do I get rid of the stop bath per the TF-4 instructions or do I keep the stop bath - per the paper instructions. I have opted to keep the stop bath but I only use it for a few seconds and add a water rinse before putting in the fixer. This keeps my fixer PH closer to where it should remain. I have ever had any problems either way with any kind of staining. I am just concerned about getting developer in the fixer. - Frank

[Donald Miller]

As I understand the matter of the chemistry involved with TF4 is that if one uses an acidic stop bath between the alkaline developer and the alkaline fixer then it would appear that the greater danger exists in neutralizing the alkaline fixer. I believe that Formulary indicates using a water bath between the developer and TF4 fixer. The major benefit of using TF4 is in eliminating the possibility of stain reduction on the negative (in film processing when using pyro developers). Some have reported this stain reduction as taking place in an acidic environment. I do use pyro and I do use a stop bath with conventional hypo (thiosulfate and bisulfite) with no apparent deleterious effects. But then, I view general stain on the negative as counter productive in that it tends to reduce negative contrast. The stain that I view as beneficial is the stain that is proportional to the negative density and in the case of ABC is not visible in the same way that PMK is. I believe that the paper manufacturer is offering suggested processing procedures based upon conventional hypo usage. At least that is my interpertation of the matter.

[David A. Goldfarb]

For paper fixing with TF-4, I use a 30 sec. plain water rinse for RC paper and a 1 min. rinse for fiber based paper to prevent staining, which seems to happen with some developer/paper combinations and TF-4. An acid stop would neutralize TF-4.