Bleaching Overexposed Negatives

[arigram]

A totally newbish question as I never had this problem before.
I made some 120 roll film negatives with my pinhole and they are greatly overexposed, not exactly "bulletproof" but a pain in the ass nevertheless.
I happen to have some Farmer's Reducer in stock.
Can I use it to lighten them up?
Will I lose shadow detail?
What is the exact process and the risks?

[Ian Grant]

It may be better to rewash, then totally bleach in a Ferricyanide/Bromide bleach, rewash in daylight then re-develop in dilute developer, more dilute than normal & with good agitation, you can stop when the dvelopment seems right.

Ian

[alkos]

Ian, do you use normal developer for the re-developement? I've tried it with iodine 1+50, paper and ilford pq universal and it didn't seem to work at all.

[Ian Grant]

You can't use Iodine bleach.

You need a bleach made up of 1% Potassium Ferricyanide & 1% Potassium Bromide, that re-halogenates the silver in the image forming Silver Bromide, this needs re-exposure then re-development.

Yes PQ Universal would wprk but best at 1+19 or even 1+29, at those dilutions it's actually a good fine grain developer.

Total re-halogenation and re-development gives far greater control than Bleaching with Farmer's reducer.

Ian

[alkos]

Ok, thanks!

However, isn't Silver Iodide image-forming? I've heard it is present in certain modern emulsions (i.e. Ilford Deltas) and therefore the Crowley's FX-1 (containing Potassium Iodide) is not as effective with them as with the oldschool ones...

And if it is, Why cannot it be reduced to silver?

[Ian Grant]

The problem is that the Iodine dissolves the silver and removes it from the emulsion without forming insoluble silver Iodide.

You could use a Ferricyanide/Potassium or Sodium Iodide Bleach, or even a Chloride bleach but Bromide is far better for re-development.

Ian

[cowanw]

Is this done in the dark?

[Ian Grant]

Can all be done in daylight.

Ian

[dpurdy]

re bleaching with Farmer's reducer, I have tried bleaching like I do prints with a dilute Ferricyanide and fix and it will definitely reduce density but for me it did a strange thing to overall contrast making it oddly flat in the bleached areas. It is good for cleaning up black backgrounds that have some texture where you wish for clear film.
Dennis

[Vaughn]

Thanks, Ari for asking the question, and Ian for answering it. I have written this down for future reference for use by our students.

I assume that farmer's reducer or similar bleach w/o redevelopment is still the way to reduce an over-all fog (such as when I tray developed an 8x10 neg but forgot to turn off the safe light in the next room).

Vaughn