homemade tubes and fixer, etc; hazards of bad ventilation

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From: Shannon Stoney (shannonstoney@earthlink.net)
Date: 07/22/01-09:04:39 AM Z


Gordon wrote:

> There is a formula for odorless fixer. This may help if its the sulpher
> odor of the fixer that bothers you. It called Kodak F-6 fixer. The
> formula from
> Carrol's Fact and Formulas

Thanks for the formula--I saved it. The thing that caused me to get sick
was not the odor per se but the acid gas that is released from fixer when it
gets contaminated with stop over time: sulfur dioxide. I was working all
last summer in a darkroom at the Glassell School in Houston that did not
have the vent turned on at all! It was not that the vent was not there; the
person who ran the darkroom just never bothered to turn it on. When I
started feeling as if there was something wrong, I asked her and the
maintenance people if there might be a problem with the ventilation, but
nobody could tell me anything, until the last day when the person running
the darkroom showed me a switch hidden behind some barrels. She flipped the
switch, there was a mighty swoosh, and the vent finally came on. I still
don't know why she did not tell us this earlier in the summer. I talked to
the director of the school and he had the vent fan re-wired so that when the
building lights come on, the vent comes on.

Then at the University of Houston, our newly renovated art building and
darkroom had its whole ventilation system cancelled, unbeknownst to anybody
but the campus architect, during the renovation process, because the
renovation was running over budget. So when we moved back in the fall, we
didn't know that our darkrooms had no ventilation. So I got sick again,
after having recovered from the Glassell School injury. So did some other
students. Some retrofits have been made to one of the darkrooms (vent hoods
over the trays), but the color processing room is still unventilated. Also
the safety and security people will not tell us the number of air changes we
are actually getting in the black and white darkroom, so I am skeptical.

I am telling this whole story to warn other people about the hazards of
public darkrooms where the ventilation is an unknown factor. I was *really*
sick for a long time and had to take six months off from any sort of
photography at all. My doctor said I probably had a chemical burn in my
lungs. This summer I am doing cyanotypes because it's the easiest and least
toxic way to make photographs at home without a darkroom. I coat out on the
porch at night and expose under a black light and develop in water in the
bathroom. I developed the 4x5 negatives in a combiplan tank outside.

But this fall I'd like to make some big negatives. As I said, I can't tray
process because I don't have a light-tight, ventilated darkroom at home (or
at school as far as I know). I am thinking the tubes might be the safest,
easiest, cheapest alternative.
>
> Cheap tubes
>
> Its not light proof and getting the endcaps off can be hard - would be
> easy if grips were glued to the caps.

So, if you make homemade tubes of PVC, all processing has to be done in the
dark?

>
> You may be able to fashion something like the BTZS tubes, see:
> http://www.darkroom-innovations.com/BTZS_Film_Tubes/btzs_film_tubes.html

The BTZS book tells how to make PVC tubes in the back of it. I don't have
it with me so I don't know if it says you have to use them in the dark. But
it makes sense that you would, because you'd need threads, like the ones
you buy have, to get a light-tight seal I would think.

>
> I believe the reason film usually needs to be fixed in a tray is the the
> fixer dissolves the anti-halation layer that is on the non-emulsion side
> of the film. In a tube the non-emulsion side is stuck to the inner
> surface of the tube, thus the fixer can't dissolve the anti-halation
> layer.

Do all films have this layer? I think I read somewhere that with T-max it
is especially hard to get the anti-halation layer off.

>
> It may be possible to dissolve the anti-halation layer after the film has
> been fixed. You could try fixing the film in the tube. Once the film is
> fixed you could fix it again in an open well ventilated area, which should
> dissolve the anti-halation layer.

That's a good idea.

thanks,

--shannon


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