Learn Me About Fixers?

Back to the well of knowledge I come... Fixers, for both film and paper, hardening versus non hardening.

I've always used Kodak Professional Fixer (powder) for film and paper, which is stated to be a hardening fixer. Seems to work fine. Recently switched to Ilford Rapid Fixer (liquid), which is stated to be a non-hardening fixer. Also seems to work fine.

Should I care whether my fixer is hardening, or not? Any recommendations?

Thank you for your thoughts.

- Danner

For modern film emulsions, and for paper, hardening vs. non-hardening doesn't matter.

For X-ray films, it might -- though generally, if you scratch that it's before the fixer step, so the hardening fixer won't help.

There are a few films with softer gelatin -- Fomapan and (now discontinued) Fortepan, have a reputation for scratching easily, but again, most of the opportunities for damage occur before fixing.

Generally, you'll get best results on both film and paper with a modern rapid fixer. There are arguments to be made on alkaline vs. neutral vs. acidic fixers, but generally, that makes little to no difference, as well. Where rapid fixer gains over older types is that it not only works much faster, it has much greater capacity (you're less likely to underfix due to exhaustion) and that goes double for films with high iodide content, like tabular grain types (T-Max, Delta, etc.).

Danner said:

Should I care whether my fixer is hardening, or not?

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Short answer: no.

Donald Qualls said:

For X-ray films, it might -- though generally, if you scratch that it's before the fixer step, so the hardening fixer won't help.

Click to expand...

Yeah, agree with that.

A hardening fixer may be a disadvantage if you apply a toner after fixing as the toner will have more difficulty permeating the emulsion. Similarly, with a hardening fixer, you may have to extend washing times for the same reason.

I use hardener separately, or hardening fixer, for one purpose only.
I do a lot of post-develop toning of darkroom prints. Some of the toning processes tend to soften emulsions, so hardener is important.
But for normal films and prints, hardener is unnecessary and can make it a bit harder to fully wash.
That being said, hardening fixer is basically okay for most people and most uses, so if you have a package you haven't opened, go ahead and use it.

Sodium thiosulfate (conventional) fixers, i.e., powdered fixers for the most part (or those mixed from scratch) are slower and don't work as well as "rapid fixers" on many modern films (TMax/Delta) due to the iodide in the film emulsion which this type of fixer is not so good at removing.

Ammonium thiosulfate fixers, aka rapid fixers, work faster and are generally better for use with modern films. These normally come as liquid concentrates since ammonium thiosulfate is difficult to deal with in non-dissolved form.

Hardeners are not generally needed unless you have films with soft emulsions. Most films from major manufacturers are hardened already. X-ray films and some "retro" films have non-hardened emulsions, but still can be fixed in non-hardening fixer with careful handling. If damage becomes a problem, a hardening fixer is probably a good idea with these films.

Fixers come in a variety of pHs, from acid through neutral to alkaline. Alkaline rapid fixers (e.g., TF-4) purportedly wash out of fiber-base paper more readily. Ilford Rapid Fixer is in the rather neutral pH category, the Kodak powdered fixer is fairly acidic. Acid helps preserve the fixer a bit. Alkaline fixers are carefully buffered to help them last.

FWIW, I like the convenience and performance of modern liquid concentrate rapid fixers, like the Ilford product. If you print lots of fiber-base, however, an alkaline fixer for prints may help shorten wash times.

With the exception of modern tabular grain films mentioned above, all fixers will do the job just fine. Conventional fixers need more time and with modern films capacity is significantly reduced.

Hope this helps,

Doremus

OK, wow, you guys are the best. Very clear. Thank you so much.

With my papers (Ilford MG RC & FB 5:1 consumption ratio) and films (FP4, HP5, with some misc. others), I should stick with the Ilford Rapid Fixer (ammonium thiosulfate).

It's good to get my chemistry environment settled, at least to have a base-line range that are selected for logical reasons.

Cheers.

If you like the Ilford Rapid Fixer, and your usage is high, the Ilford Hypam rapid fixer in 5 litre containers is functionally the same, and can be quite economical. It is directed at the commercial user and, ironically for the purposes of this thread, differs from the Ilford Rapid Fixer in that it permits addition of hardener (which you can't do with Ilford Rapid Fixer).

MattKing said:

If you like the Ilford Rapid Fixer, and your usage is high, the Ilford Hypam rapid fixer in 5 litre containers is functionally the same, and can be quite economical. It is directed at the commercial user and, ironically for the purposes of this thread, differs from the Ilford Rapid Fixer in that it permits addition of hardener (which you can't do with Ilford Rapid Fixer).

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Yes. Hypam without the hardener functions identically to Rapid Fixer. I buy whichever is cheapest in the 5L size.