On Tue, Mar 2, 2010 at 3:11 PM, John Graves <[email protected]> wrote: > Ann, > > Thanks...I was reading elsewhere that stopbath was essentially vinegar so > why not.
Stop bath is essentially dilute acetic acid, same as vinegar. The advantage of Kodak Indicator Stop Bath is that it has a dye in it that turns purple when the acid content is consumed, so you can see in a darkroom when to change it. The dyes are biodegradable and have no environmental impact. Vinegar is cheaper. ;-) > .. Now what about the developer. I would use something like Ethol > UFG unless this is really toxic and there is anything that is not. > Inquiring minds want to know .....or at least one mind. Some developers have trace small amounts of heavy metals in them (most anything made with Metol, for instance). Kodak's XTOL, however, has very little if anything that is not biodegradable ... it's mostly a variation on Vitamin C. I moved to XTOL for virtually all of my processing at the end of my time doing B&W film work, that is unless I used a C41 process film which I simply let the local lab process for me. Fixer has small amounts of sodium thiosulfate in it, which is typically used in pesticides, etc. California doesn't even list it on the toxicity pages. However, exhausted fixer has small amounts of silver salts in it, which are heavy metals that are pretty reactive. Color chemistry can be all over the map with regards toxicity and environmental impact ... but why anyone in their right mind would do a home color chemical darkroom today is a mystery to me. - In the minute amounts that even a seriously busy home B&W darkroom produce, none of the waste products from B&W photography have much environmental impact. Local regulation of environmental hazard is actually more important from a political and legal standpoint than any environmental impact. - The silver salts in exhausted fixer are the most significant outputs and should be handled as toxic waste when in quantity ... it should be recycled ... for instance, when I was in the photofinishing business in a shop that ran an average of 150 135-36 rolls a day, we sold the waste out of the film and paper developer machines on a regular basis for the buyers to reclaim the silver. For an occasional roll of B&W film, I doubt there is any significant environmental impact. - I've never dealt with a septic tank so I have little to recommend one way or another regards to that. - Read up on local legal requirements for photographic waste products with regard to disposal. -- Godfrey godfreydigiorgi.posterous.com -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
