wrote:
On May 10, 7:09 am, Jean-David Beyer wrote:
BVStaples wrote:
Greetings all:
I recently picked up a Polaroid 545 and some film, along with the
requisite sodium sulfite and other goodies, and I have some questions
about the sodium sulfite, but cannot find the answers anywhere!
First, is whatever I put in the tray a one-shot use, or can I use the
same solution for multiple negatives? How do I know when it's
depleted? If it's a one use situation, so be it. I do plan on shooting
and then coming home to process, rather than develop in the field.
When you use it, scuzzy stuff comes off the negative, that usually settles
to the bottom. But not all of it. Eventually, it may redeposit on the
negatives. Just before that happens ;-) , replace it. I would not keep it
over a day because the stuff oxidizes into sodium sulphate that is less useful.



Second, once used, what's the proper disposal method? I have friends
who pour everything down the drain, and then those who recyle
everything.
Dumping it down the drain increases the oxygen demand of the effluent, but
home users probably do not dump enough that the sewage treatment plants
would even notice.

It is technically non toxic, but I strongly advise against drinking it.
Causes asthma attacks in some people, and IIRC, you can turn blue if you
drink enough of it. Recall that even table salt will kill you very soon if
you consume too much of it. The dose makes the poison.



Thanks in advance.
Brian


No. it is technically toxic because it turns the hemoglobin in your
erythrocytes into methylhemoglobin which does not carry oxygen well.
When a person who is blue (and still alive) turns up to the E.R., the
routine way of treating them is to give them methylene blue, which
paradoxically is also blue, but demethylates hemoglobin.
You could neutralize your sodium sulfite with hydrogen peroxide
solution, or rusty steel wool, or expose it to air in the sunlight for
a few days.

David

What I meant was that sodium sulfite is allowed as a food additive in USA.
The dose makes the poison.

You could oxidize it any number of ways into sodium sulphate, but in
home-use quantities, it is probably not worth the bother. I suppose you
could use sodium permanganate as well, but you would wish to use the right
amount. One reason you do not want to keep hypo-clear solutions too long is
that they oxidize to sodium sulphate anyway (because of the oxygen they
absorb from the air).

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