Formaldehyde - Final Wash Hardening bath

James1

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Hi All,

Is it possible (or desirable even) to use a non-hardening fixer followed by a hardening final wash using a formaldehyde solution?

I'm asking particularly with regard to using PMK as a developer - would such a bath remove the stain?

Thoughts welcome!
 

darkroommike

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What you are describing is an old school C-41 stabilizer. Formalin/formaldehyde in a solution with Photoflo in distilled water. Very good stuff, horrible smell and hard on your lungs. I have no idea what it would do for/against stain.
 
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James1

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Thanks Mike, Andrew.

I would imagine some tanning does go on in the developer - but, I'm just looking to harden the emulsion further. I still have a stash of Efke 100, where this seems to matter a bit more.
 

Doremus Scudder

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PMK will harden the emulsion a bit. You only really need to harden the emulsion if scratches, etc. from handling when wet are a problem. Once dry, the emulsion is pretty hard. You don't mention why you need to harden. If you can process and dry without damage, there's really no need.

If you really need to harden, I'd forget the formalin and go with a hardening fixer; you will have one less step and less handling (i.e., less opportunity to damage a neg). Just be aware that you'll need to wash longer. There's good old Kodak Rapid Fixer with the little bottle of hardener. Ilford Hypam is designed for a hardener as well, which you would need to purchase separately, and there's always good old F-6 or F-8 fixers that you can easily mix yourself.

Best,

Doremus
 
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James1

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Thanks Doremus. I wouldn't mind mixing a suitable fixer if I needed to. I'd really only want to harden the Efke film I still use. I never have dust issues with other film, but I have found in my workflow, that the soft Efke emulsion *really* attracts/embeds dust unless I have a hardening step, either between developer and fixer, or at the final wash.

I was wondering about formalin particularly (I don't mind handling it) since I am sure I read that hardening fixers will strip the PMK stain. If they don't, then that would be great!

Best,

James
 

Rudeofus

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Hardening fixer is much more difficult to wash out, and its shelf life is inferior to a more neutral fixer. Therefore I am not sure whether a hardening fixer is indeed less hassle. Formalin can be used together with a wetting agent like E-6 final rinse. It's not even an extra step, since a final rinse in deionized water is a good idea anyway.
 

john_s

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koraks said:
I never heard of this. There's a long and ongoing debate about acid fixer reducing the stain, but that's a different issue than hardening.
Click to expand...

Traditional hardening fixers containing alum need to be fairly acidic in order to harden. It's the acid that can apparently reduce the desirable staining.
 

mshchem

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Kodak's old Special Hardener SH-1 . This is a formaldehyde hardener for softened emulsions.
10 mL of 37% formaldehyde, 6 grams of sodium carbonate monohydrate dissolved in 1 liter of water.

As noted formaldehyde is nasty, especially 37% , my concern anymore is if I buy a chemical, what do I do with the remains.

I use Kodak Rapid Fixer w/ hardener for all my b&w films. It's a old habit for me. Unique and Freestyle ship ground no problem. B&H won't ship the hardener portion.
 
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James1

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I found th reference, from The Book of Pyro no less. In the third edition, 1992, p.18, Gordon Hutchings states:

"Fixers with hardening agents reduce the image stain. The use of non-hardening fixers allows optimum staining."

So it looks like the best way forward here would be use the Kodak SH-1 or the C41 stabiliser as a final wash as I definitely would like to keep the stain...
 

Doremus Scudder

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koraks said:
I know it's a long debate and the last word as probably not been said about it, but I never noticed any effect of any fixer on stain.
Click to expand...

Me neither. I use Ilford Rapid Fixer or Hypam for the most part with film. Plenty of stain on my PMK negs. I've not used conventional acid fixers, however, like F-5 or F-6 with PMK. One wonders, however, what fixers Weston and Adams used with their pyro developers; I'd wager it was good old Kodak F-5 or the like. At any rate, Hypam or Kodak Rapid Fix with the hardener would work fine for the OP.

I agree with Rudi above that a final rinse with formalin as a hardener would be better if the only reason for the hardener is to keep the film from attracting dust. I kind of assumed that the problem was emulsion damage during processing. Even better would be a clean drying environment

Best,

Doremus
 
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