Unhealthy Reaction to Darkoom Chemicals???

dancqu · Sep 14, 2004

Leon said:
I spent this evening in the darkroom.
I used Ilford Hypam instead of my TF-4 type fix ... Leon

Plain fix is sodium thiosulfate. Use it. TF-4 I think is quite alkaline. That
may cause more ammonia to enter the air than if it were neutral. You
should be able to judge that.

I find nothing wrong with using S. Thiosulfate. I'm presently working
my way through a liter of A. Thio. from Photographer's Formulary. I
add nothing to it and use it very dilute one-shot.

You should consider entirely workable alternative chemistry and
methods prior to bothering yourself with gas masks and
unnecessary ventilation. Dan

Leon · Sep 14, 2004

dancqu said:
TF-4 I think is quite alkaline. That
may cause more ammonia to enter the air than if it were neutral.

Thanks Dan - I was using TF-4 because it is alkaline and all the reported benefits that brings. Now understand that the ilford rapid fixers are reasonably neutral, so I think I'll be sticking with them and use an HCA.

dancqu said:
You should consider entirely workable alternative chemistry and methods prior to bothering yourself with gas masks and
unnecessary ventilation.

A good tip in part , although I dont think ventilation in a darkroom could ever be considered unnecessary - my health is worth much more than my photos!

Ole · Sep 14, 2004

Alkaline fix is generally a good idea, but it doesn't have to be so alkaline that it's painful!

Alkaline plain fix is easy to make, and hardly smells at all. If "rapid" fix is required, it can be made acidic or about neutral.

My "OF-1" fix is a little alkaline, and can easily be made non-ammonium by replacing the ammonium chloride with the same amount of sodium thiosulfate. Or just skipping it altogether. Or replace the sulfite with bisulfite (and drop the alkali), and it's acidic. Or drop the alkali (metaborate or bicarbonate), which makes it slightly alkaline but poorly buffered.

juan · Sep 14, 2004

Or use TF-2, a sodium thiosulfate alkaline fixer - I smell no odor at all from it.
http://simmonsphotos.com/Formulas/TF-2.html

juan

dancqu · Sep 15, 2004

Ole said:
Alkaline fix is generally a good idea,... Ole

I wonder if that has ever been tested. I know Bill Troop whose TF-4
is very alkaline, promotes an alkaline fix.

Alkaline plain fix is easy to make, and hardly smells at all. If "rapid" fix is required, it can be made acidic or about neutral. Ole

I use fix, sodium or ammonium, straight. I doubt there are any benefits
from 'making' a fix; perhaps a little preservative for those who put it back
in the bottle. The sodium runs neutral although a little alkaline would
be more reasonable. I'd think the ammonium salt of thiosulfuric acid
should be about neutral.

but poorly buffered. Ole

The ammonium salt will provide some buffering against alkaline additions where as the sodium will provide none. The thiosulfate ion will provide some buffering against acidic additions. Dan

Unhealthy Reaction to Darkoom Chemicals???

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