Potassium bromide

Tomas Segeblad · Mar 29, 2019

Hi,
I recently got a box of expired TMax 400 and made a test today. It´s good for 400 ISO but the film has a weak fog. Does anyone know how to mix potassium bromide and what amount to add to HC-110? And time correction?

Thank you,
Tomas

Anon Ymous · Mar 29, 2019

Why bother? You can always print through fog. If it has lost some sensitivity, then downrate it until you get good results. Adding Potassium Bromide will needlessly complicate things.

barzune · Mar 29, 2019

If the film is age fogged, you might consider benzotriazole, rather than potassium bromide, to clear the fog.
Dan

Rudeofus · Mar 29, 2019

Either way, typical starting points are increments of 0.5 g/l Potassium Bromide. This assumes a developer with normal dilution, i.e. HC-110 1:16 or 1:32. If you use higher dilutions, you might try 0.25 g/l increments.

David Lyga · Mar 30, 2019

Anon Ymous said:
Why bother? You can always print through fog. If it has lost some sensitivity, then downrate it until you get good results. Adding Potassium Bromide will needlessly complicate things.

Although this is true, you will gain grain in the rendering. Also, printing through fog can mitigate the contrast and be a general pain in the butt. Fogged negs are ugly. BUT ... bensotriazole can help matters,as might potassium bromide. I mix the BZ with a little baking soda. - David Lyga

Anon Ymous · Mar 30, 2019

David Lyga said:
Although this is true, you will gain grain in the rendering. Also, printing through fog can mitigate the contrast and be a general pain in the butt. Fogged negs are ugly. BUT ... bensotriazole can help matters,as might potassium bromide. I mix the BZ with a little baking soda. - David Lyga

The OP mentions weak fog, so that's why I wouldn't bother adding any kind of antifogant. Had it been heavy fogging, there would be a reason to try to reduce it IMHO.

Rudeofus · Mar 31, 2019

BTW David Lyga has written an excellent guide for treatment of expired film. Must read for anyone dealing with old film IMHO.

Potassium bromide

Tomas Segeblad

Anon Ymous

barzune

Rudeofus

David Lyga

Anon Ymous

Rudeofus

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