U of S | Mailing List Archive | alt-photo-process-l | Re: I have a question

Re: I have a question

On Sat, 20 Oct 2007, Ryuji Suzuki wrote:

....For example, draining canola
oil down the drain may not be technically banned in many
I can't imagine using enough canola oil to POUR leftovers anywhere... But, if one happens to have more than a tsp. of liquid animal fat left after cooking (say pan-seared pork chops), it can be drained into a paper cup, & put into refrigerator (or in winter left at room temp); it soon hardens enough to discard with solid waste.

But that's not why I'm writing, which is to point out that potassium ferricyanide is used for other purposes than bleaching silver gelatin. For instance, I mentioned it (if I mentioned it) as part B of cyanotype. And I daresay substitute silver bleaches, whatever they might be, patented or not, couldn't be counted on for the same purposes.

I also suppose that much less k ferricyanide is used in cyanotype than in bleaching: A bleach requires a *bath,* up to a litre or more, perhaps. Cyanotype emulsion is applied only to coat the image area, say, 20 or 30 ml. (It might even become something else in the process, tho that's beside the point.)

.... However, regulation of chromium
in sewer water is a different matter and you should contact
your local government body.
Actually, come to think of it, I described that very contact in clear, complete, credible and, in my opinion, quite interesting detail, on this very list, in fact in this very thread that you append so authoritatively.

Sorry you missed it.