Mixing formaldehyde in developer, bleach or fixer?

Athiril · Aug 12, 2010

This is probably a question for PE again

I was just wondering for stabilisation if mixing formaldehyde ino developer, bleach or fixer would have a negative effect on any of these?

IE: Short term use/mixing - mix into dev, bleach or fixer right before use - will it still have its desired stabilisation effect and not have a negative impact on these processes?

And long term - Mixing it into the concentrate or working solution of any of these parts - would it keep?

I know people will tell me to just do a normal final rinse.. but this is something I am curious about and want to know.

Photo Engineer · Aug 12, 2010

Yes and no.

Any ammonia containing solution will generally react with formalin. Almost any bleach will oxidize formalin to formic acid. So, you have to be careful. Also, formalin tends to degrade in strong acid or alkali.

Using formalin in an alkaline fix using sodium thiosulfate will make a very nice hardener fix with a fair life.

PE

Athiril · Aug 12, 2010

Thanks for the tip on the sodium thiosulphate. I guess that answers that

ooze · Aug 13, 2010

Formaldehyde is also a strong allergen, so be careful.

2F/2F · Aug 13, 2010

You don't want to mix it into the Final Rinse (or into Photo Flo)? It was the former final step (called "Stabilizer") that contained the formalin AKAIK.

Are you processing Vericolor or another older C-41 film?

Mike Wilde · Aug 13, 2010

I have mixed & used lithographic developers with para-formaldhyde as part of the formula. Lots of PPE and ventilation at play when I mixed that formula up. Has a gamma higher than any other developer I have ever see. I use it for line type lith film.

Photo Engineer · Aug 13, 2010

Mike Wilde said:
I have mixed & used lithographic developers with para-formaldhyde as part of the formula. Lots of PPE and ventilation at play when I mixed that formula up. Has a gamma higher than any other developer I have ever see. I use it for line type lith film.

Works fine with no ammonia and has limited lifetime.

PE

Athiril · Aug 15, 2010

It's a curiousity, its not for older colour processes, nor automatically C-41 either.

It's for stabilisation of colour dye in general, modern/contemporary products.

Photo Engineer · Aug 15, 2010

This was done in the Ektaprint C process in the '60s by using a Sodium Hypo fix with Formalin and the pH was about 9. It hardened and stabilzed the dyes. It was called AFHF or Alkaline Formalin Hardening Fix.

PE

Mixing formaldehyde in developer, bleach or fixer?

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