Caffenol chemicals?

koraks · 2025-11-01T12:43:30-0400

pentaxuser said:
Are higher speed films susceptible to fog and if they are why are they?

Yes, they are because they're fast. They're sensitive so they also respond more strongly to heat and background radiation.
I personally don't think an anti-foggant/restrainer is really necessary when using reasonably fresh or slow film.

pentaxuser · 2025-11-01T13:05:55-0400

koraks said:
Yes, they are because they're fast. They're sensitive so they also respond more strongly to heat and background radiation.
I personally don't think an anti-foggant/restrainer is really necessary when using reasonably fresh or slow film.

Thanks Just to be sure, if a fast film, say HP5+ or Delta 3200 is reasonably fresh then KBr is unlikely to be needed? Assuming the user has properly stored the fresh film then at what age might it be affected by fog and if it might be affected, can you still simply print through it without it affectíng the print ?

Thanks

pentaxuser

npl · 2025-11-01T13:31:29-0400

I tested 100 ISO film (fomapan 100) with and without iodized salt and could see a clear difference in fog level between the two. I prefer less so I use salt, but that didn't mean that the fog couldn't be print through.

koraks · 2025-11-01T13:58:57-0400

pentaxuser said:
Thanks Just to be sure, if a fast film, say HP5+ or Delta 3200 is reasonably fresh then KBr is unlikely to be needed? Assuming the user has properly stored the fresh film then at what age might it be affected by fog and if it might be affected, can you still simply print through it without it affectíng the print ?

That's what I'd expect, yes. Of course, a restrainer when added in small amounts will subtly affect the tonal curve, especially in the toe region. So the statement "without affecting the print" will always be a bit problematic if it's taken in a literal, absolute way. So I'd add "for all intents and purposes."

pentaxuser · 2025-11-01T15:45:35-0400

koraks said:
That's what I'd expect, yes. Of course, a restrainer when added in small amounts will subtly affect the tonal curve, especially in the toe region. So the statement "without affecting the print" will always be a bit problematic if it's taken in a literal, absolute way. So I'd add "for all intents and purposes."

Thanks That covers it for me

pentaxuser

Chuck1 · 2025-11-01T16:14:14-0400

So iodized table salt will work instead of KBr, with less smell

koraks · 2025-11-01T18:15:08-0400

Chuck1 said:
with less smell

I'm surprised to hear that. KBr is odorless both as a solid and solution. I do think that bromine gas has a kind of 'poopy' odor. Is it possible that somehow a tiny bit of bromine gas evolves if KBr is added to caffenol?

Chuck1 · 2025-11-01T19:30:14-0400

That was a question, it has been mentioned over the part few days

Caffenol chemicals?

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