[Noisebridge-discuss] Chemistry at Noisebridge

[Mark Cohen]

It depends on the type of processing. 

For B+W processing, the only chemical that needs "special" treatment is fixer (ammonium thiosulfate), this is because if used properly (over and over and tested until bad) will contain high amounts of soluble silver that will be detected in the water supply and if you have enough, you can be fined for.

Developer is considered harmless and stop is diluted glacial acetic acid, like vinegar.

If you're doing E6 or K14, other considerations need to be taken into account. 

If you're doing tin types, cyanotypes it should be fairly safe.

If you're doing Daguerrotypes the whole process is deadly due to mercuric oxide used in the development process. 

.. I doubt that anyone will be doing enough processing and dumping of fixer that would be dangerous. I don't know where they moved to, but the Harvey Milk Photo center used to take used fixer and have it dealt with properly (removed the silver and had a 3rd party take the chemicals out).

Mark 


On Mar 25, 2010, at 3:45 PM, Ian Atha wrote:

> Do the darkroom chemicals need special processing or any special
> considerations before they get dumped into the trunk sewage?
> 
>> -organizing a kid-friendly ph experiment day (possibly this weekend!)
>> where we make various anthocyanin based ph indicators from produce.
> 
> That sounds amazing :) Noisebridge for Kids! Corey McGuire
> <coreyfro at coreyfro.com> also mentioned something about a kids-oriented
> activity that involved making fridge magents, or something of the
> sort.
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Mark Cohen
markc at binaryfaith.com

Science is a way of skeptically interrogating the universe with a fine understanding of human fallibility.
-Carl Sagan, 1996