Sil Horwitz (silh@iag.net)
Sun, 14 Feb 1999 17:17:40 -0500
At 01:11 PM 1999/02/14 -0800, Hal Faulkner wrote:
>Sodium sulfite is a major ingredient in many photographic chemicals. It is
>used as an activator in developers, it is also in most hypo clearing agents
>(washing aids) such as Kodak's KHCA. Sulfur dioxide is not a problem with
>these chemicals when stored properly.
Chemical photography is impossible without sulfite, and anyone who calls it
dangerous is speaking only to the sulfite-allergic people. (Look at any
bottle of wine - they all state they contain sulfites, a vital ingredient.)
As to giving off sulfur dioxide, unless you are in a sealed environment
(and you should always have adequate ventilation no matter where you are)
such small quantities are released in photographic processes that there is
no problem in a small, personal environment. (Incidently, sodium sulfite is
not normally a developer activator, though some fine grain developers use
it somewhat for this purpose. Its main use is as a preservative - it
combines with any loose oxygen that is in or gets in the water, and
prevents the developing agent from oxidizing. Only a little is used in
color developers because oxidation of the developing agent is what combines
with dye intermediates in the film to form the colors. It is also used in
washing aids because it's readily available; strangely, sodium chloride
will do the same job, but is not used because it may react with some of the
other ingredients. Sulfite is safe.)
>But, please check with your local/state authorities about the disposal of
>these materials. At the very least, contact the Occupational Health and
>Safety officer at a nearby university. S/he should be able to point you in
>the direction of the information you need to have in order to be a safe and
>good neighbor.
Not that I want to ignore any laws, but unless you are doing something
really dangerous in a large commercial environment, I recommend you don't
contact the authorities. Most of them read the same material you do, but
find a different meaning, and you will usually be warned about using any of
our materials. Sulfites are next to chlorides as far as being inoffensive
is concerned, but you have persons who are not knowledgeable look up sodium
chloride (table salt), find out it's a combination of lye and hydrochloric
acid, and that will frighten them! Find out for yourself - if you can't
manage these materials knowledgeably and safely, then you shouldn't be
using them. Farber's book has all those warnings in an effort to "CYA" (and
if you don't know what that means, ask anyone in government and law!).
Learn more about this at the '99 APIS in Santa Fe this July!
Sil Horwitz, FPSA
Technical Editor, PSA Journal
silh@iag.net
Visit http://www.psa-photo.org/
Personal page: http://www.iag.net/~silh/
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